[DR KRISTEN HOLMES] (0:00 - 0:23)
You think you are a night owl, but no, you've just bypassed your natural pressure for sleep. That's often why maybe you're so exhausted you fall asleep, but that's why you wake up in the middle of the night. Make it very clear to our body that it's daytime, and very clear to our body that it's nighttime.

When we're up working, we're coming back online, we've got bright lights, we're engaging our computer, we're stimulating our mind, our body is receiving cues that it's not time to wind down.

[ANGELA FOSTER] (0:23 - 0:33)
For the woman in midlife, she's raising her kids, advancing her career, she feels like her nervous system is being asked to carry more than it ever has in her life. What would you say is the number one thing she can do?

[DR KRISTEN HOLMES] (0:33 - 0:48)
I think sleep-wake consistency is foundational. When you can stabilise your sleep-wake cycle, everything else follows. Hormones, your satiety hormone, ghrelin, leptin, cortisol, melatonin.

Sleep consistency is the behaviour that trumps everything. I would say movement and getting outside are two of the most important things that you can do.

[ANGELA FOSTER] (0:48 - 0:53)
One of the things I've been paying a lot of attention to is the sleep stress, and the stress during the day.

[DR KRISTEN HOLMES] (0:53 - 1:13)
Stress is not bad, but the idea is that you want to buffer it with these little mini moments of rest, where you're intentionally deactivating, you're bringing your nervous system into a parasympathetic state, so you can then re-engage your next task with focus and energy. 30 seconds of slow-paced breathing, 30 seconds of the physiological side. It doesn't have to be massive, but just telling your system, let's bring it down.

Dr. Kristen Holmes.

[ANGELA FOSTER] (1:14 - 1:18)
Oh my God, it's so amazing to be with you in person in London. I know.

[DR KRISTEN HOLMES] (1:18 - 1:26)
Welcome. Thank you so much for having me. I have so much admiration for the work that you do, and yeah, just grateful to be in your orbit.

[ANGELA FOSTER] (1:26 - 2:03)
I am so grateful to you for everything you're putting out, and this incredible book, Aligned. In it, you talk about how we should be sleeping and going to bed and waking up at a regular time, but this has had me gripped. I just think there's so much in it that really gives us a guide for human performance, female human performance as well, at its best.

For the woman in midlife, who's right in the middle of that sandwich, she's raising her kids, she's advancing her career, maybe has elderly parents. She feels like her nervous system is being asked to carry more than it ever has in her life. What would you say is the number one thing she can do?

[DR KRISTEN HOLMES] (2:03 - 2:16)
Well, that's a beautiful question, and I think we're all, as you started reading off that laundry list, I can check a lot of those boxes, certainly in midlife and 52, so I guess I'm slightly beyond that, I don't know. That's midlife.

[ANGELA FOSTER] (2:16 - 2:17)
Yeah, that's midlife.

[DR KRISTEN HOLMES] (2:17 - 4:25)
I have two children, 19 and 18, they're 18 months apart, both going off into college and have lots of demands with my work and my schedule, and I understand all of that. I think one of the things that I've come to realise is that having some semblance of control over our state becomes really important if we want to be able to navigate these transitions in our life with grace and maintaining a version of ourselves that we can feel proud of. I think when it comes to behaviours, chapter three, I talk a lot about sleep and circadian rhythms, and I really think that is foundational.

That's the place to start, because that impacts the health of your autonomic nervous system, so your ability to respond and react and adapt to stress is very much contingent on the health of your autonomic nervous system, and sleep is just such a big driver of that. In fact, we know that sleep-wake consistency, which I think is the behaviour that we want to try to stabilise if we can in midlife, because that is a driver of sleep quality, which is when we think about the measurement of heart variability, which is a proxy for your autonomic nervous system health, we know that sleep quality is literally correlated with HRV. If you're not getting consistent sleep, quality becomes more challenging, and if we don't have quality sleep, we're less able to be able to respond and adapt and react to stress in a functional way.

To me, that's the core, is stable sleep-wake timing, driving sleep quality, which helps our autonomic nervous system resilience. That's the first big thing to, I think, try to address and get right. I think where maybe we lose the plot a little bit, or maybe we don't have the right information, is that a lot of what helps facilitate sleep-wake consistency certainly is the decisions we're making pre-bed and all of that, but it's very much what's happening during the day that sets up whether or not we're able to fall asleep and stay asleep.

I think that's where sometimes we don't recognise, I think, the power of some of our daytime behaviours in helping facilitate that sleep-wake consistency.

[ANGELA FOSTER] (4:26 - 5:02)
That's definitely made a huge difference to me, really focussing on that circadian rhythm. When you think about, I speak to so many women, and because they've got so much on, they will quite frequently, they'll be at work all day, then they'll come back, they'll do some family time, and then they'll log back on in the evening. I know you've studied this in relation to performance.

I saw in the book, you talk about the increase in productivity, in innovation, when we don't do that and we focus and have boundaries around our hours. I also know, as a former corporate lawyer, it's really, really difficult. I'm running a business, isn't it?

That temptation to go back on, how do you approach that?

[DR KRISTEN HOLMES] (5:02 - 7:38)
I'm probably 80-20. 80% of the time, I'm very strict with the boundaries. 20% of the time, like everyone else, I have to engage, whether it's work or I have a deadline that I need to make or I have a presentation the next day and I need some extra time.

Oftentimes, that falls in a couple hours before bed. It's maybe not ideal, but I think, again, if we zoom out and if you look at your month, that you can say, all right, 80% of the time, I want to try to create as much routine and stability as possible. We could come back to how that routine creates physiological stability, which is so important for human performance.

For women in particular, I can talk about some of those data, but knowing that it doesn't need to be perfect, but we need to have a strategy. That's where I think modern life makes it challenging. We're not by a fire anymore where the fire goes out, we all go to sleep.

We can keep that fire ablazing all night long if we want to with artificial light, and some people do, but I think the recognition that that does actually come at a cost and the data I talk about is that it does come at a cost to your productivity, to your mood, to your energy levels the next day. What's insidious about it is that, and why maybe we ignore it, is that we might not see it immediately. That's the whole problem is that we can't actually perceive our own declines mentally, physically, emotionally, and I'd argue probably spiritually.

They happen very subtly and we think we're getting away with it and then all of a sudden we have a big health event or some sort of crisis, stress, exhaustion, burnout, just even accelerated ageing because of these mini choices. I think sometimes we just have to zoom out and look at it in the context of the month and be like, all right, I'm going to have to probably bypass my maybe natural pressure for sleep a few times this month, but be strategic about it. I hear a lot of pushback, well, that's not very spontaneous, that's not living life.

I'm like, well, modern society doesn't set us up for success. If you think you don't need a strategy with the laundry list of things you just listed, you're out of your mind. You're out of your mind.

That is the reality of modern life. The counterbalance to modern life is to have a strategy. It doesn't mean that you can't be spontaneous, you can't live life, but you just have to pick and choose your moments.

You can maintain a sense of balance and proportion that enables you to have the longevity and quality of life that I think we all desire.

[ANGELA FOSTER] (7:39 - 7:59)
It's so true. It is a constant challenge. Without a strategy, you're just at the behest of everything else.

That's the thing. So well said. You end up flinging yourself in all sorts of directions.

100%. Also, as we go through midlife, I know you've studied the menstrual cycle, you've also looked at menopause. Women have so many challenges.

We have pregnancy, postpartum, it's just constant, isn't it?

[DR KRISTEN HOLMES] (7:59 - 8:04)
It's crazy when you actually think about it. I'm like, how do we even do it?

[ANGELA FOSTER] (8:04 - 8:05)
How do we do it?

[DR KRISTEN HOLMES] (8:05 - 8:08)
Exactly. It is amazing what women can do.

[ANGELA FOSTER] (8:08 - 8:18)
We just show up from a very young age. I know looking at my from the beginning of your menstrual cycle, beginning at school, where you show up the same every single month, regardless of what's going on.

[DR KRISTEN HOLMES] (8:18 - 8:19)
That's kind of the expectation.

[ANGELA FOSTER] (8:19 - 8:42)
Yes, it is the expectation. Then when you get to midlife, it can feel like, oh my God, there's another mountain. I feel like you've just climbed so many mountains and then all of a sudden there's this other one.

How much is, in the book you talk about exercise, improving menopausal symptoms, what are the key things we can do to help us, whether we're having hormone therapy or we're not, what are the key behaviours that will support us?

[DR KRISTEN HOLMES] (8:42 - 9:58)
I don't want to say that once you're in that transition that all is lost, but I think for women who are listening, who are not in that transition to perimenopause yet, I would say that the behaviours leading into the transition are really important. I think for women who are listening, who are maybe in their 30s, think that sleep maybe doesn't matter, this is actually the time frame to build those skills. I think once you're in perimenopause and things start going awry hormonally, now if you don't have a good foundation, I think symptoms become amplified.

I think if you're in it and maybe you haven't built these behaviours, and you talk about this all the time, it's never too late to start. Movement is a great place to start. I would say movement and getting outside are two of the most important things that you can do.

We do see in our data that women who have higher amplitude, so looking at their heart rate amplitude, so how the contrast between the day and the night, the greater that contrast, the less severe symptoms are and the less frequent symptoms are across women who are menstruating, perimenopause, and menopause.

[ANGELA FOSTER] (9:59 - 9:59)
Interesting.

[DR KRISTEN HOLMES] (9:59 - 10:00)
I know.

[ANGELA FOSTER] (10:00 - 10:05)
This is doing high intensity during the day.

[DR KRISTEN HOLMES] (10:05 - 11:54)
What does that mean? It's more of just having a contrast. We're not able to measure the clock, so I'm very careful about saying it's circadian amplitude because I'm not actually measuring amplitude.

We're measuring the physiological amplitude. We're looking at heart rate, skin temperature. When there is more contrast between the day and the night, so your circadian rhythm is kind of acting in the way should and your behaviours are kind of facilitating that, we see less severe symptoms across menstruation, perimenopause, and menopause.

That's kind of why I say light during the day. When you have more natural light, artificial light, you're telling your body that it's time to be awake and alert, that helps set you up for a better night's sleep. We know that when women in perimenopause, menopause, are not getting sleep, that just creates this real vicious cycle.

Activity, lots of movement during the day, absolutely working out, but building in micro movement throughout the day. I talk in my book about exercise snacks. I think for me, that has been a game changer.

When I started seeing these data, I'm like, wow, activity throughout the day matters. It's not just an hour workout. Yes, that's great, but you want to try to build in movement throughout the day.

A lot of us are just really sedentary. We just need to think a little bit more intentionally about how can I build in these micro movements throughout the day to create that contrast. Our body expects to be moving during the day.

When it doesn't, our amplitude flattens. That amplitude, that flat amplitude, again, we don't create that contrast. As a result, I think our sleep is probably not as good as it should be.

[ANGELA FOSTER] (11:55 - 11:59)
By amplitude, you mean things like light, heart rate, movement, activity.

[DR KRISTEN HOLMES] (11:59 - 12:46)
Those impact the amplitude, right. We want to be engaging in behaviours that make it very clear to our body that it's daytime and very clear to our body that it's nighttime. When we're up working, we're coming back online and we've got bright lights.

We're engaging our computer. We're stimulating our mind. Our body is receiving cues that it's not time to wind down.

It's not safe to sleep. You end up releasing all of those hormones that are performance enhancing, right. You think you are a night owl, but no, you've just bypassed your natural pressure for sleep.

Now your body's in threat, is in a state of threat. That's often why maybe you're so exhausted you fall asleep, but that's why you wake up in the middle of the night.

[ANGELA FOSTER] (12:47 - 13:17)
Yeah, that makes sense. I remember speaking to a sleep scientist who was saying that we ask too much of sleep. Sleep is about repairing, deep rest, recovery, growing our muscles, all these different things, detoxification.

What we're currently in modern day times is asking ourselves that sleep must cause us to relax, whereas it's the other way around. We must relax in sleep entry so that sleep can do its job as opposed to sleep being the only time that we actually stop during the day, which I think it commonly has become. I couldn't agree more.

[DR KRISTEN HOLMES] (13:18 - 15:58)
That's kind of the red thread throughout the book is that we need to think about because we are in a situation where we have lots of stress throughout the day. It's not bad, right? A lot of that stress is creating that contrast, which is healthy, but I think the recognition that we need to just balance stress with appropriate levels of rest is really what we're after.

You want to prevent that stress accumulation so by the time you are ready to go to bed, you're not just so wired, but tired. You hear that all the time. That's negative stress accumulation throughout the day.

Building in just many moments of rest throughout the day. You've just had a stressor, just 30 seconds of slow-paced breathing, 30 seconds of the physiological sigh. It doesn't have to be massive, but just telling your system, okay, let's bring it down.

Let's go from this high stressed state to a relaxing state. Being able to kind of toggle between those states is really a healthy, flexible nervous system, which is really what we're after, is being able to kind of context switch. If you find yourself, well, I can't even bring my heart rate down, that's a sign that you are overstimulated, overactivated.

If we were measuring you, we'd probably see a very low HRV. If we're measuring over time, we'd see a suppressed HRV over time. That means you're kind of chronically activated.

You're not basically toggling between these two states of rest and digest and fight or flight. We want to be able to toggle appropriately between those. A lot of folks, I think back to your sleep scientist point, a lot of folks are, they get to that moment where they need to get into sleep and they basically haven't managed stress throughout the day, so they just can't sleep.

Back to the original point of sleep kind of starts the moment you wake up. In terms of managing stress throughout the day, getting that contrast as much as we can, lots of light, lots of movement. Then before bed, if you have to log on and do some work, really after you shut it all down, commit to shutting it down, and then engage in some slow-paced breathing, you want to try to basically tell your body that it's safe to sleep.

One of the cues for your body that it's safe to sleep is your heart rate actually needs to come down. Doing, engaging in slow-paced breathing before bed is one of the best strategies. I do it literally every single night.

I do about one to two minutes of physiological sigh as I'm sitting on the side of the bed, and then I lay into bed and I do a couple minutes of slow-paced breathing, and then before I know it, it's morning. It's just a really, it's a great way just to signal to the body that it's safe to sleep.

[ANGELA FOSTER] (15:58 - 16:01)
Are you counting when you're doing this or you're just breathing gently in and out?

[DR KRISTEN HOLMES] (16:01 - 17:44)
Yeah, so I do like physiological sigh is basically double inhale followed by an extended exhale. We know from the literature, there's a great paper published in 2023 of September in Cell Press where they looked at physiological sigh up against a lot of other modalities that were purported to reduce anxiety, and the physiological sigh emerged as the most efficacious of those four modalities. The other ones are great, but the physiological sigh was the best.

Basically, that just involves a double inhale followed by an extended exhale. It's kind of a let go, isn't it? Yeah, so it's just like a double.

It's almost like you're that crying kind of... We do it kind of naturally, actually, when we're trying to regain our breath, but we can intentionally deploy this as a way to relax. I do the physiological sigh throughout the day after stressful meetings.

Stress is not bad. Stress can be good. It can be bad, but the idea is that you want to buffer it with these little mini moments of rest where you're intentionally deactivating.

You're bringing your nervous system into a parasympathetic state so you can then reengage your next task with focus and energy. What the study showed is that after engaging in the physiological sigh, participants showed that they had reductions in anxiety five hours after doing the session. The protocol in the study was five minutes, which is a long time, but you can imagine if you're just doing a minute here, a minute there, kind of adding up the five minutes over the course of the day.

That's not what they studied, but I think it would have a similar effect in terms of just reducing anxiety short term and just definitely helping with sleep. They saw increases in HRV, decreases resting heart rate, so there's an autonomic nervous system kind of cardiovascular benefit to this slow-paced breathing, or this physiological sigh.

[ANGELA FOSTER] (17:44 - 18:22)
I've definitely seen, when I look at my clients and we introduce these practises, they sound so small. For everyone watching or listening, you think, oh, it's not going to make a difference. It's only a minute or two minutes.

It makes a huge difference. It does. The other one I do is when you finished a meeting, particularly, say, for example, you're presenting or something, you're giving a lot of energy, is to then let that move through your body by going out for a walk, just five minutes, and it just clears everything.

You always get that investment of time back because you come back clearer, you're sharper, you can think, and yeah, you can be truly present to those that you're with. And when you're out taking your walk, do you take your phone? Do I take my phone?

I would say 50-50. Half and half, I have my phone.

[DR KRISTEN HOLMES] (18:23 - 18:23)
Yeah, yeah.

[ANGELA FOSTER] (18:23 - 18:30)
Sometimes I'll go, like if I've got a really busy day, my phone will be with me because I might take a call. Most times, I actually like to just decompress.

[DR KRISTEN HOLMES] (18:31 - 18:34)
You're getting a movement. You're getting a natural light. I'm getting the light.

Yeah, exactly.

[ANGELA FOSTER] (18:34 - 18:54)
The light, I wanted to ask you, seems to make a massive difference. Obviously, in the UK, you and I were talking before the show, you live in Boston, you have a bit more light than we do here. We seem to have so much light exposure, particularly in late spring into summer, and then we're very, very deprived come November through February.

I mean, all of us in Northern Latitude, we're the same. We've just short days.

[DR KRISTEN HOLMES] (18:54 - 18:55)
Really short days.

[ANGELA FOSTER] (18:56 - 19:11)
And what I notice is that HRV seems to be significantly higher in summer. Do you think there's... First of all, is that correct?

That's something I've observed myself and with clients is, and is there a way of us holding onto that by the time we get to January, February?

[DR KRISTEN HOLMES] (19:11 - 19:43)
I love this question so much. We have a paper in review right now. It's a seasonality paper looking at exactly this question.

Yeah, it's a really beautiful paper. The investigator, Dr. Greg Grosicki, is one of the staff scientists on my team. He's just so brilliant.

But yes, that phenomenon is exactly... We observe that in all latitudes, but it's more pronounced in Northern Latitudes, for sure. There's a bigger suppression in HRV.

And I think the key is... So I've worked on this myself and to a point where I've actually... My HRV is higher during the winter because I think I'm over-indexed.

Oh my goodness.

[ANGELA FOSTER] (19:44 - 19:46)
That's a challenge for me this winter.

[DR KRISTEN HOLMES] (19:46 - 20:52)
I would see it improve, improve. Yeah. But I think because I'm so aware and conscious of it.

So I work out outside almost more in the winter than I do in the summer. I'm more active, I think, generally across the day in the summer. I probably have higher strain, but my workouts outside, I'm able to go harder because it's cold.

For me, for some reason, the heat really reduces my capacity. So I seem to get fitter in the winter. It's probably because I cross-country ski too a lot.

Do you? Yes. And that's known as being one of the...

It's a cardiovascular just kicker. Amazing for longevity, isn't it? It's so good for longevity.

I've always loved cross-country skiing and just have really gotten into it the last few years. It's probably my favourite sport at this point. I just absolutely love it.

And I love being in the snow. I love being outside. I love being among the trees.

I just love it. So I'm actually quite happy in the winter in a lot of ways, especially when there's snow on the ground. I can participate in sports, but the snow sports.

But yeah, it's possible, but you just have to be conscious and intentional about how you're training.

[ANGELA FOSTER] (20:52 - 21:09)
How much of it is influenced by actual light? Because in the winter, we're very covered up and skiing, you'd be covered up, but you're still maintaining yours. So I've often wondered, would being very disciplined around a red light therapy or full-spectrum sauna help somewhat in terms of elevating it during the winter?

[DR KRISTEN HOLMES] (21:09 - 21:43)
It would absolutely help. Yeah. It would in the data.

That's the idea. It's just known, okay, light is going to be minimised. And this is kind of how I think about it.

Light is minimised. So when it is light outside, you got to get outside. You actually have to engage with the elements in order to get, because there's lots of photon energy even in a winter sky.

And so you just have to make sure you get out there when it's at its highest, at its peak, which is around noon for everyone. It's a challenge. And I think supplementing with kind of happy lamps and artificial light is super helpful.

[ANGELA FOSTER] (21:44 - 22:28)
Yeah. All of those things. One of the things I've been paying a lot of attention to on my rube that I love is the sleep stress and the stress during the day.

I find it really, so I'm always like competitive to see, can I get, I love to, like my husband and I, when we go train in the morning in the gym, we do like a little comparison on the treadmill and he's like, let me show you mine. And we're always looking for a flat line and doing as flat as we can get it. And it's super helpful for me because I know that like there's some foods, you know, things like digestion, for example, some things I digest better than others.

And I can see that show up. Or if we've had a late meal, when I'm taking my kids to clubs, you know, sports clubs, and then we come back, we eat a bit later. And the first part of the night we'll have this sleep stress.

I find it really, really helpful to track.

[DR KRISTEN HOLMES] (22:28 - 23:22)
I think that's one of the reasons why I haven't been, you know, not that I'm opting out of jet lag, but I don't have any physiological perturbations. You know, I showed you my data, right? Like I've been in London since Tuesday and it's very much meal for me.

So I basically, I've stopped eating at like 4 p.m. like every day since I've been here. Basically, the only thing my body has to worry about is it doesn't have to compete with digestion, right? I can focus totally on restoration and recovery.

And, you know, my resting heart rate this morning was like 47. I had a really big breakfast, really big lunch, basically got all the macronutrients I needed prior to 4 p.m. And then 4 p.m. on, my body's able to regenerate. I got a little massage last night.

And then, yeah, asleep by 10 and, you know, woke up at 6, you know, and felt totally restored. And I think a lot of that is the meal timing. It makes a big difference.

I think it does.

[ANGELA FOSTER] (23:22 - 23:23)
Yeah.

[DR KRISTEN HOLMES] (23:23 - 24:22)
And so when you're in a situation where you're travelling, I think that is a very powerful lever to just kind of help you get back into balance. From my perspective, that seems to help a lot. And we know from the data on WHOOP, to your point, it's very, very clear that a late night meal is one of the biggest saboteurs or detractors of both sleep and recovery.

If you are going to have food before bed, make it high protein, you know, high quality protein, limit the carbs and fats. That seems to not have too big of an effect for, you know, healthy adults. Mike Wormsby's lab at Florida State University did a study where they looked just exactly at that, looking at high protein and if it would have a negative effect on sleep recovery and it didn't.

I think for folks who are struggling with their metabolic health, you know, it's probably easier just to have a more strict kind of 12 on, 12 off type window. But I think for healthy adults who might not be able to get the macronutrients in throughout the day, having some protein before bed isn't the end of the world by any means.

[ANGELA FOSTER] (24:22 - 24:23)
It doesn't make such a difference.

[DR KRISTEN HOLMES] (24:24 - 25:03)
You know, high fat, high carbohydrate kind of meals, heavy meals right before bed. There's a thermoregulatory perspective, right? So digestion heats up your body, right?

And to sleep, you need to cool your body down. And then there's also the circadian piece, right? Of just like the non-photic kind of inputs that impact your peripheral kind of system, right?

So when we're eating, when our body doesn't expect it, that is after the sun goes down generally, our body isn't primed to metabolise food. We're less insulin sensitive. It's going to interfere with our sleep, right?

So there's the thermoregulatory perspective and then there's also the circadian perspective and both kind of compete, you know, for sleep.

[ANGELA FOSTER] (25:04 - 25:16)
How much do you rely on data versus your intuition? Because in the book, there's quite a bit about journaling and just how much it's helped you in intuition as well. Yeah.

How do you balance those two things?

[DR KRISTEN HOLMES] (25:16 - 28:46)
I've always been a writer. I've always journaled, you know, like I had a diary when I was a kid and I, you know, I wrote a lot. And then after kind of in my mid twenties, I really got into journaling almost as a form of therapy, just trying to make sense of my life and where I wanted to head.

And so started just being, I guess, way more intentional about writing my thoughts down. And that's been enormously helpful, I think, in being able to, I think, step out into the world with a little bit more confidence about who I want to be and how I want to live. So, yeah, journaling is really powerful.

And I think it does help you connect with your thoughts on a level that allows you to build that intuition, you know, so you kind of feel like life is a little less forced, right? You've already kind of rehearsed it. You've already written down, you've already written it down, you know, and so you're able to just, I think, make sense of things faster, I guess, is what it's helped me with in terms of relationships and just how I interact with the world just generally.

But I think with data, one of the things that I've noticed is that it is reinforcing. It validates that, oh, wow, this actually really does work for me. And then there's other instances where I'm like, wow, this really doesn't work for me, you know?

And, you know, alcohol is a good example, late night meals, you know, just some of the more kind of daily tactical things, you know, you can start to learn what actually is sleep and recovery promoting and what isn't. And, again, we have so many options with modern life that being able to kind of see the impact, like, objectively of these inputs, I think, can be really powerful. But I never want to minimise, like, the subjective experience, too, because that really does matter.

And I would say I have, like, this blend of both, which I think is really what I try to advocate for in Aligned is that, you know, data is great, but we do have to build that intuition. And one of the areas that I have built that intuition is around food. That's an area where I don't actually use a lot of data.

I really do go by...I have a basic understanding of nutrition. I'm not a nutrition scientist, but, you know, just in my studies, you know, you end up, you know, in physiology, you end up understanding, I think, nutrition on a, you know, on a very basic level. But one of the things that I found is that fuelling for activity requirements is really kind of how I think about food.

So I have an activity, how am I going to...I want to eat in a way that allows me to have the energy I need to engage in the activity and also recover from the activity. So I kind of, in the book, I read it from this lens of recovery, of, you know, eating in a way that allows you to have enough energy, but also be able to recover from it, so you're not in a situation where you're ever really under-fuelling or over-fuelling, right? And I did, you know, about 15 years ago, I tracked my food meticulously, and I think that was actually important because now I really understand, I can look at food and eyeball it and understand, you know, how much protein is in that.

And obviously, if things are labelled, I think the labels are getting better, but that's an area that I don't use a lot of data around. It's really just intuition, eyeball, and just feeling, did I have the energy I needed for the activity and was I able to engage with a level of alertness and focus and concentration that felt good? Was I able to run as hard as I wanted to run?

Did I meet my physiological intent for that workout or whatever? So those are the things that I pay attention to now, and that's largely intuitive.

[ANGELA FOSTER] (28:47 - 28:54)
And how much does your own data drive your workouts? Do you pay attention? Does it change what you might do on any particular day?

[DR KRISTEN HOLMES] (28:54 - 30:43)
Yeah, I use, that's a great question, I use heart rate variability coefficient of variation. So on Sunday, I kind of look at my profile. So I calculate the day-to-day variability in my HRV, which we now have in Whoop Coach.

Yes, I've seen that. You can ask it. Finally got it in.

I had to publish a couple of papers to validate the HRVCV, but we got it in, which is great. And so, yeah, you can just tell, hey, Whoop Coach, can you calculate my HRVCV for the last seven days? And we need seven days of continuous data in order to kind of get a reliable HRVCV.

We published that, which was, I think, a really good piece of work for the sports science space to show that seven days is kind of required in order to get a reliable kind of effect. But I use that adaptation profile to understand how I might want to modulate the next week. So next week will be a pretty hard training week for me because I have a really stable HRVCV this week.

And because I've been doing just longer, kind of slower efforts, and just basically just knowing that I'm travelling and I've been lifting, but I haven't really been running that hard. So next week I'll do a couple really hard runs, a longer run, a couple lifts. I'll definitely have a suppressed...

Well, with HRVCV, it's the opposite. So it's basically the lower your HRVCV, the better adaptation. The higher the HRVCV, the less good the adaptation.

So I'll want to basically manipulate my HRVCV so I can basically increase it a little bit next week, and then I'll go back until more restorative the following week. So I definitely try to go like that. Every other week, one week is hard.

One week is less hard. One week is hard. And that seems to work for me in terms of basically keeping my HRV in an upward kind of slope and my resting heart rate kind of down.

[ANGELA FOSTER] (30:43 - 30:46)
You're kind of going hard, easy, hard, easy. Not easy, but lower.

[DR KRISTEN HOLMES] (30:46 - 30:57)
Yeah, yeah. And that easy will depend. Maybe it's moderate.

Maybe it's hard, moderate, easy, moderate, hard, easy. I basically just kind of manipulate the training.

[ANGELA FOSTER] (30:58 - 32:17)
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It's going to kind of go spiky on a graph.

[DR KRISTEN HOLMES] (32:18 - 32:21)
And that means you're not really adapting functionally to the stress you're putting on your body.

[ANGELA FOSTER] (32:22 - 32:26)
And you're not managing your recovery enough in comparison.

[DR KRISTEN HOLMES] (32:26 - 34:00)
You're probably, yeah. And I would say that for the modern human, who's not Tadej Bogacar, the Tour de France winner, who I can talk about his date in a second, which gives you a really nice contrast, that physiological stability is possible if that's like your job, right? But for most humans, it's not our job.

But when we become aware of it, we can start to see, ah, okay, I don't want to have these big egregious highs and lows in my HRV. I want more stable HRV. I want more stable respiratory rate.

I want more stable resting heart rate. Like the stability physiologically is a indicator that you're adapting functionally to your environment. And you're not putting too much stress on your body, more stress that your body can handle.

And once you kind of get that stability, you start to understand how you can manipulate that in ways that allow you to kind of continue on a positive trajectory in terms of your cardiorespiratory fitness, right? And that's kind of when I started really thinking about this, kind of in 2017, I started really like, all right, like I started having all this data from my time at Princeton and then my time at WHOOP. And I'm like, all right, this stability thing, there's something there to it.

So that's kind of how I've been thinking about my data. And I've gone from in 2017, my resting heart rate variability, my heart rate variability was 60 milliseconds. My resting heart rate was 55.

And now I'm kind of in the low 50s, high 40s for resting heart rate. I mean, my HRV today was 134, 128 yesterday.

[ANGELA FOSTER] (34:00 - 34:01)
She's more than doubled it.

[DR KRISTEN HOLMES] (34:01 - 34:55)
More than doubled it, yeah. My average over the course of the last year is 103. Right.

So you can modify your HRV, which is kind of the big red thread in the book, that we can modify our autonomic nervous system. We can make our autonomic nervous system more resilient if we understand the physiological and psychological factors that influence it. We've talked a lot about the physiology and not so much the psychology, but in the book, I bridge these domains of physiology and psychology because I think we treat them very much separately, but they're so integrated and they impact our internal state in ways that are so profound.

So if we understand what moves it around, we can then apply our effort more intentionally and have more control over the trajectory of our ageing and our health. And so that's really been, I suppose, the project in the last decade or so.

[ANGELA FOSTER] (34:56 - 35:37)
If you're getting value from this show, the single best thing you can do to help us keep bringing you the highest calibre guests is to subscribe or follow wherever you listen or watch. It takes 10 seconds, but it genuinely makes a difference to the quality of the guests we bring you week after week. And you go into it so beautifully in the book.

I think if you... I would encourage people to follow it as you go through, right? Because every single area is dealt with, your circadian rhythm and sleep, your fitness, the journaling, the nervous system, all of these pieces come together.

When you look at your own, because that is pretty transformational, increasing your HRV like that, what do you think if you had to name the top three to five things that you think have influenced it the most, what would those be?

[DR KRISTEN HOLMES] (35:37 - 37:27)
Sleep-wake consistency, for sure. That number one, I think the biggest lever is stabilising your sleep-wake cycle, because when you can stabilise your sleep-wake cycle, everything else follows. Hormones, your satiety hormone, your ghrelin, leptin, cortisol, melatonin.

It just goes on and on and on, right? So I think sleep-wake consistency, it's hard, but it is worth the effort. If you want to minimise, I think, a lot of pain, reduce illness, injury burden, sleep-wake consistency is at the very top.

And we see this in our own data. I talk about it. There's also other published data.

When we think about the Wolf, Danny Windrids work that was published in January, 2024, where he basically showed sleep-wake regularity was a greater predictor of all-cause mortality than sleep duration. Obviously, normal ranges of sleep duration matter, but sleep consistency is like the behaviour that trumps everything. And then he also just published a paper that showed sleep-wake regularity was a greater predictor of disease than sleep duration.

So sleep-wake regularity, there is just something very, very powerful there. Stabilises circadian rhythms in ways that are so powerful and have this downstream effect. Because when you are getting, and again, sleep consistency is a driver of sleep quality.

When you have quality sleep, you can wake up and you can move. You make better food choices. You are able to retain cognitive clarity and focus and concentration throughout the day.

You have less crashes. You have better mood. You have more patience, more tolerance.

That's life, right? And that's, I think, how we want to live our life. So sleep consistency, sleep quality.

And then I would say getting strength training. If you're not doing anything.

[ANGELA FOSTER] (37:28 - 37:29)
I love strength training.

[DR KRISTEN HOLMES] (37:29 - 37:29)
I know.

[ANGELA FOSTER] (37:32 - 37:35)
Psychologically, right? As much as anything else, it creates order in my mind.

[DR KRISTEN HOLMES] (37:36 - 38:36)
Feeling strong. My daughter and I talk about this all the time. There's nothing better than feeling strong.

Like moving throughout the world, being able to lift your suitcase. Yeah, I don't need your help. I got it.

Just being able to just have basic strength. So I would say resistance training is kind of the place to start. But cardiovascular fitness matters too, right?

And we see this in the data. People who only lift have less good cardiovascular profiles, right? Not surprisingly, right?

They have higher resting heart rate and lower HRV. So you want to work your heart. So I think start with strength training, get out of breath a couple times a week.

It doesn't have to be crazy, but whatever that means for you, whether it's a brisk walk, whether it's a jog, whether it's getting on a bike for 30 seconds, take 30 seconds on, a minute off. 30 seconds, go as hard as you physically can, take a minute off and repeat that six times. Do that a couple of times a week.

It's crazy that you don't need insane amounts of stimulus to create these adaptations, right? Especially if you're starting from zero.

[ANGELA FOSTER] (38:36 - 38:40)
Yeah, it's true. If you're short on time, doing it at high intensity is just so much better.

[DR KRISTEN HOLMES] (38:40 - 39:31)
For sure. And then getting a lot of that low level zone two work. In my book, I don't even really frame it as exercise.

I call it training for very intentional reasons, but we'll say exercise here because I haven't explained why I use training. But zone two for me is just a recovery modality. And it's very clear in our data.

And I think if we just thought about zone two as a recovery modality and not exercise, a lot of the confusion that you see online about zone two would fall away because it actually, it's so recovery enhancing. You're creating this beautiful base that helps build capacity that allows you to go hard, right? It kind of creates this engine that allows you to reach those upper thresholds of your heart rate.

So that's certainly what we see in the data. And I hopefully at some point we'll publish these data. There's just a long queue.

[ANGELA FOSTER] (39:31 - 39:53)
On zone two, when you talk about that, how much does it matter which bit of zone two you're in? Do you need to be at that upper end? So like very much more deliberate around it.

Because I think the thing that I struggle, I'm sure people listening to this will be, is like with time. So for example, you go to the gym, you lift some weights, I can do the high intensity stuff. But then say I'm going out with my dogs for a walk or something.

I'm not going to be in zone two because my heart rate just won't get up.

[DR KRISTEN HOLMES] (39:53 - 39:54)
You'll be zone zero one.

[ANGELA FOSTER] (39:54 - 40:07)
It'll be exactly. It'll be pretty low. And so it's quite difficult because then you've got to set aside specific time for that.

And I can definitely see that it does improve things. But I would say out of everything, it's probably the first thing that falls away when I'm busy.

[DR KRISTEN HOLMES] (40:07 - 40:44)
And I think that's the thing to probably let go of. I would say that the high intensity and strength training, those are the priorities for sure. I think if you can afford, if you have the time to do the zone two, that's going to be just a bonus.

But yeah, I mean, I think just maybe trying to increase the pace of the walk with the dog, maybe. But honestly, I don't know that we have enough of this data. Well, I know Taddei Boccaccia, five time Tour de France winner, he's on Whoop.

And we had the ability to look at his data from January to throughout the tour. It was really fascinating, but he actually does zone one. I think, you know.

Interesting.

[ANGELA FOSTER] (40:45 - 40:47)
So he's not actually going that hard.

[DR KRISTEN HOLMES] (40:47 - 41:18)
No, no, he really isn't. Obviously, he's the fittest human on the planet, I think behind that cross-country skier, but they're both incredibly fit. But yeah, he's kind of operating in zone one.

So I don't know. I think there's probably a lot we don't know. I think the bottom line is that when you're engaging in a slower, longer efforts, you are basically enhancing recovery in a way that allows you to engage harder efforts with kind of more intensity.

[ANGELA FOSTER] (41:19 - 41:27)
Yeah. So it's kind of like, I suppose, how high do you want to take it? If you think about a tall building, zone two is building a stronger foundation.

Yes, that's a perfect analogy.

[DR KRISTEN HOLMES] (41:27 - 41:29)
So you can kind of go to higher levels. Yes, absolutely.

[ANGELA FOSTER] (41:29 - 41:30)
Yeah. So you need both.

[DR KRISTEN HOLMES] (41:30 - 41:48)
I think so. If you have time, but a lot of us are really busy. And for me, same thing.

If I am short on time, I'm going to do 20 seconds on, 20 seconds off, 10 times. I'm going to lift for 20 minutes and boom, I'm done in 30 minutes. And that is great.

[ANGELA FOSTER] (41:49 - 41:56)
So you were saying, so sleep regularity, strength training, doing some zone two, these have all contributed to your HIV. Yeah.

[DR KRISTEN HOLMES] (41:56 - 42:39)
Anything else? Yeah. And then I would say just lots of light during the day.

So important. And I think if you can pair that light with just these little stress mitigation tactics throughout the day, that will help contribute to a better sleep at night. And then I would say, you know, stopping eating two to three hours before bed for most adults is, I think, an awesome strategy that's free, available to most of us, requires some discipline and kind of coordination, potentially, depending on your culture and your family dynamic and schedules and stuff.

But that is incredibly recovery and sleep promoting.

[ANGELA FOSTER] (42:39 - 43:17)
All of those things. And I think what's so interesting is in the book, you talk about right at the beginning, how different things were many years ago for you, right? When you, when your kids were young, both you and I have two kids that left 18 months apart.

I mean, it's chaos. You just, there's no sleep. And you fell asleep while driving at that point, I think.

And you, you had so much on in terms of running your grandmother's estate and just, there was so much pressure. It called you to make a change, but how did you go about that? Because somebody who really is in those depths at the time, it's really hard to pull yourself out of it and actually create space.

[DR KRISTEN HOLMES] (43:17 - 46:53)
You can't even see it. You know, and this was 18 years ago now, you know, where I had, I had an 18 month old and then my daughter was just born. So she was, you know, just days old.

And I learned that my, my Nana had just gone into hospice and my, my mom had died, you know, many years before that. I was like kind of the only one, I was the executor of the estate. So she, I lived in New Jersey at the time.

She was in Massachusetts. It was about a five hour drive. My husband and I at the time had a seasonal business.

So he was running that business. And I was kind of just left to my own devices to, to a degree, you know, and, and I think as women, we're just so bad at asking for help. You know, I was like, I can handle it.

I can manage it. And meanwhile, I was the division, I was a head coach of, of a university. So I had lots of demands I had, you know, I was running camps on my campus.

I had a club that just, there's a lot going on. And then meanwhile, managing my, my Nana's estate, Princeton, you know, our preseasons looming in August. And I was driving back and forth.

I, you know, I had my babies with me the entire time I'm breastfeeding. I'm, you know, doing all the things. And yeah, I just, I fell asleep at the wheel.

It was so scary. Right. That, that moment, thank God, of course, you know, obviously I woke up, that was the moment where I was like, I need to change my life.

Like, this is not sustainable. And I just committed at that point. I was like, there's got to be, that this is not, I need to get sleep.

I need to figure out how to sleep. That's when I really got into sleep and circadian rhythms and started, I remember watching a TED talk with Dr. Russell Foster. He's a sleep scientist from Oxford.

And, and that's, that's really what got me, I think, excited about this idea that I had hadn't really explored up to that point. That, wow, there's, if I could just get some sleep, I'd probably be a lot better off in terms of like my daytime functioning. And, and so I went really deep and, and that's obviously, I ended up getting my PhD in sleep and circadian sciences.

But, but yeah, I, that, that was a terrifying moment for sure. But I think that was the moment where, and that's, I think, why I write about it in the book is, is I just don't want people to almost die to have to make changes, you know? And, and I think that's where, and as we said, I said earlier in the, in the podcast, like you, we can't always, sometimes these happen so subtly that we can't even perceive it.

Like, I didn't even know that something was wrong, really. I was so far. I didn't even know what feeling good felt like.

Yeah. You lose touch with it. Like, yeah.

I was so far from like, I hadn't had a good night's sleep and I don't even know, a decade. It's like, we, we don't have to live that way, you know? And it, it will come at a cost, you know?

And you think about all the people who do fall asleep at the wheel and who die and who kill their entire families in the process, right? Like, I mean, that was, I was, that was almost me. And I think that was, that's what I realised.

And I was like, God, I gotta do my life differently. And, and there were so many things in my life at the time that were off track with my relationship, with everything, you know? And, and so it was a, it was a pretty big audit and a, and a big reckoning and, and I didn't do everything at once.

I need to figure out how to get some sleep. And I, my dad, my, my mother-in-law, like, I just started asking for help. And my mother-in-law stayed pretty much like the entire month of August, you know, as I was navigating preseason and just to just help me take care of the kids.

I got a nanny and I know that, you know, it took a lot of resources that I didn't really have, but I was like, I gotta, you know, I gotta marshal some resources here to, to be able to manage all this and get myself, get my health back on track.

[ANGELA FOSTER] (46:54 - 48:25)
That's the thing, isn't it? I think as women, we don't ask enough and it has to get bad. It was very similar for me.

I think the thing for me that's been so transformational is all the stuff that you talk about in the book is it's, and I'm not saying I do everything perfectly by any stretch, but it is the things that you talk about in terms of the light exposure, the movement, the regular sleep times that have transformed my mood. Because, you know, when I was at my worst having these bipolar episodes, I was told I'd never be off meds and I've transitioned completely free of that, which for me is amazing that, you know, when you work, you talk about these biological rhythms and the importance of that in the human body and how that affects our mental health and our physical health. And I can fully say, you know, it's huge because it was considered something that wasn't even going to be a possibility for me.

And it's through doing those things and being consistent and it's the power of those tiny habits that just compound, don't they, over time. I think, Kristen, quite a lot of people look at when they're busy in particular. I speak to so many people and they're like, should I be worried about my HRV?

Because I look at it and it's like 17, I'm so busy. And they maybe aren't moving around enough at this point. I know you say, and you make this very clear in the book, it's very individual for people and you can increase it over time.

But is there a point that somebody, like, do you have numbers from looking at it with all the data that you have where you're like, actually, this person, if you're looking at your data and it says this, you do need to pay attention. Like, it is that crunch time before we get to the point of falling asleep at the wheel or mental health issues or something else.

[DR KRISTEN HOLMES] (48:26 - 51:07)
Well, on the mental, just with bipolar, we know circadian misalignment is present in almost 100% of psychiatric disorders. So this idea, and oftentimes a circadian disorder whereby your sleep-wake variability is like four to five hours off of what a healthy individual would be, we know that that is highly correlated with issues like bipolar disorder. So circadian alignment, it's the place to kind of look first if you want to get yourself back on track and want to improve HRV.

And we know that mental health is literally correlated with HRV as well. And I have an example in the book where an individual wrote in just on Reddit, and he basically showed six months of therapy and his starting baseline was something like 30, and then his ending baseline after six months was 60. And he's like, I improved 30 milliseconds just by engaging in therapy.

And it was amazing, right? So I think the bottom line, HRV is modifiable, but it does move slowly. And it's not just the physical stuff, it's the mental stuff too, which is, you know, a big part of Aligned is really, you know, if you've got unresolved trauma, for example, like your baseline HRV is going to be lower, right?

If you had lots of trauma as a child, your baseline HRV is going to be lower. And knowing, and to your point about it being individual, roughly 47 to 60% is genetic. So the point really is when you get onto a platform, you start observing your HRV, I wouldn't worry too much about that starting number necessarily.

You just want to engage in behaviours that are obviously going to be increasing it over time, knowing that it does move relatively slowly. For folks who are kind of, you know, you don't, I think it's easy with data to kind of get obsessed over the numbers. But I think if you just ignore the numbers and really just think about, all right, I'm going to engage in these behaviours that I know have the biggest impact on my autonomic nervous system, which is everything that we've talked about on this podcast today.

If you can just do a few of those consistently, you will build more resilience, which will, I think should, you know, manifest in the data that you're looking at. But I think the key is managing stress throughout the day, you know, thinking about these circadian behaviours more intentionally, so you can set yourself up for a good night's sleep and create conditions that allow you to fall asleep and stay asleep. Like that, that's kind of the key.

And it's, it's a little unglamorous, but that's really it.

[ANGELA FOSTER] (51:07 - 51:09)
It makes a massive difference.

[DR KRISTEN HOLMES] (51:09 - 53:38)
And what's great is we don't have to pay a lot of money for that, right? Like a lot of the stuff we're talking about is just literally free. But yeah, I think that, that nervous system health, you know, I think for folks who maybe have unresolved trauma, that could be a place to start too, because that is going to keep your autonomic nervous system not able to kind of switch context appropriately, right?

Oftentimes when we have unresolved trauma, we kind of stay stuck in that fight or flight, which is going to basically, which is suppressing your HRV, right? So I think that's also a place to look, which is a harder place to look. But I think if you are kind of struggling to build this resilience that you desire, that could be what's keeping you stuck.

The other thing that I talk about in the book, our relationship, you know, between, of trust and fear is, is another kind of how we think about our emotions. I think a lot of us who maybe have unresolved trauma kind of look at life through the lens of fear, right? And, and so I think that's just understanding that relationship is important, right?

And there's domains or dimensions kind of inside trust and fear that are important things like time and expectations, attachments and memory. And I talk about that in the book, you know, when we are operating from place of fear, we can be very much stuck in the past or the present or the future, right? Which creates a lot of anxiety, right?

We have, we struggle being present. Expectations were more outcome focused potentially, right? Versus process driven and value driven.

And that, again, that creates a lot of fear, right? Which is going to suppress HRV, right? Create a less robust autonomic nervous system, prevent that context switching attachments.

Do we have rigid attachments? Do we have fluid attachments, right? We want to have fluid attachments, right?

We want to be around people who nurture our values, who allow us to grow, right? If we are around people and have, are in jobs where we feel stunted, that, that are kind of creating this, this rigid attachment that also will have an impact on our, on our nervous system. So that the kind of the team framework, framework and M is just memory, right?

How we, how we think about the past is, is also, can create a important context for us in terms of our overall health and functioning. But that's also, again, if you're finding yourself in, in a state where, you know, I just feel off, like these are just places you can look.

[ANGELA FOSTER] (53:39 - 54:44)
Yeah. Last, last question or penultimate, should I say, you have achieved so many things. I don't know who this, I've heard that this is attributed to Oprah, this idea that, and I might be misquoting it, that you can have everything, but you can't have it all at once.

And I would say that your book is actually showing us how we can seek to achieve everything that we want at once. But what you said there was, and that, and that is so, so helpful. And I would encourage everyone to go and check out the book because it's such a manual for that.

But what you were saying there is so interesting because when we come from a place of fear, we are outcome-driven and yet the outcomes that you've achieved, Kristen, are pretty incredible. You've raised two children. You are, you know, global head of human performance at Whoop.

You've written this incredible book. You've done a PhD. Like the, the number of achievements I could go on are really incredible.

How do you hold your goals alongside your values, but at the same time, just focussing on that process and releasing expectation? Because many people struggle with this and you've done it so beautifully.

[DR KRISTEN HOLMES] (54:45 - 57:51)
This has been my life's work. I mean, this is the, my biggest issue is that my entire self-worth, my entire identity rested on outcomes. My whole, like for a very, a big part of my life, you know, certainly as a kid, you know, and it's, this is the, you know, kind of the, the paradox of mastery, right?

Is that it's almost like you have to be kind of outcome focused to, to a degree, right? And in order to kind of get the outcome, you have to be so ultra focused, right? And you almost have to have your identity wrapped.

But what I've learned is that that actually isn't the case. And so inarticulate, like as much more articulate in the book, I think I'm talking about this, but I guess I don't want people to feel like ambition and achievement don't matter. Okay.

And that is why I'm just careful in how I kind of frame this because I don't think those are, that's not bad. And I'm ambitious and I like to achieve things where I've been able to reconcile. This is that my identity and my self-worth is not contingent anymore on outcomes.

And that's what I've been able to let go of. And that's probably, I would say when I look at my life, just letting go of that has made me a better, a better mother. It has made me better at my work.

I feel prouder in how I show up for, for things. It's made me operate certainly with less fear, way more trust. I can access those emotions of trust.

I can access joy. Finally, when I was operating from a place of, of pure outcomes and just having my self-worth tied to those outcomes, there was not an ounce of joy, very little joy. And, you know, and so I would encourage people to, you know, to zoom out for a second and just think, all right, how do I, what do I really care about?

What are the things that I value in my life? And then create the conditions that allow you to back into that. And then ask yourself the question, are my behaviours a reflection of the things that I say that I value?

And this is where, you know, once you start living like that, when there is conflict between what you say you value and your behaviours, you get this internal dissonance that is so palpable that you, you, you almost like feel sick to your stomach. And I guess I'm at that place where I immediately feel tension when I go outside of my values or I start making decisions that are not aligned with who I say I want to be in the world. And, and I had to train that muscle though.

Like I didn't have that muscle for like such a long time. And, and so I think, you know, how do, how do I do it? I literally just try to live my values like that.

That's honestly, that's my only goal in life is to live my values so I can have joy and I can have energy to, to, you know, be able to, to, you know, give to the people I love and give to the things that I love. That's really like at a very basic level, how I think about my day.

[ANGELA FOSTER] (57:52 - 57:56)
And a beautiful way to live your life because it is, as you say, aligned.

[DR KRISTEN HOLMES] (57:56 - 57:57)
Yeah.

[ANGELA FOSTER] (57:57 - 57:59)
Which brings you peace, I think.

[DR KRISTEN HOLMES] (57:59 - 59:31)
It does. And you start having, you stop having to like access your willpower, you know, like it just, it just happens, it's natural. You know, like when you are really living from a place, when you're really living from your values and, and you're consciously aware of that, like your decisions, like what you say yes to and what you say no to is so obvious.

Like you, this life becomes clearer, you know, like you, you, you are living in alignment, you know? And, and I think that's, that's been, I think the beauty of the last, I suppose, 10 or 12 years for me is, is I've, I've just felt like all I've really been paying attention to is living my values. And in, and I started that project probably 15 to 20 years ago, but it's, it's taken a while to actually build that muscle and actually kind of get to that point where I do feel that internal tension when I'm not, you know?

And, and I think that's, that's such a beautiful place to be, you know, cause that you can make clear decisions about your life and who you spend time with, who you don't, like Pablo, you probably know Diego Perez, he's an author and he's so, I love how he talks about the nervous system. When you build that awareness internally and you're more connected to yourself, you can actually start to feel if the energy you're around is energy that serves you, you know? And, and, and you, you can make better decisions.

I think about who you hang around with and who you don't, you know? Like your nervous system should feel calm around the people you're spending the most time with, right? And, and I think that that is a, that's really important.

[ANGELA FOSTER] (59:32 - 1:00:54)
Really important. And I think that is the promise of the book, right? Is that you come to the end of it and you feel much more aligned because you know who you are.

If you go through all of the exercises and the prompts for me, it's going to be a book that I go back to again and again, because I think that, and I don't know if this is how you intended it, but I was listening to it on a very long drive. Then I was picking up reading it and it struck me that it's the kind of book that you read and you can almost like, almost like watching a really incredible movie. You want to go back and see all the little pieces that you missed and you can then take individual chapters and just focus on them.

So there is literally an entire blueprint for fitness, for health and longevity that you can go follow. There is a blueprint for journaling. Do you know what I mean?

And coming in touch with yourself and living in alignment with your values, for sleep and circadian rhythm. And there's all the science and everything to back it up. I think it's a phenomenal job.

I really, really just, I, I'm so grateful to be here with you today. It's so nice to be able to do it in person. I know we've done this before on the internet, but this has been really special because what you've put in there and it has given us a little insight just to the kind of beautiful and kind heart that you have.

It's not just success, but you know, the whole heart that you give to this book. So thank you, Kristen. And thank you for coming today.

Really, really amazing. Where can people connect with you? Go buy the book?

[DR KRISTEN HOLMES] (1:00:54 - 1:01:55)
Yeah. So Amazon, Barnes and Noble, Target, I think, you know, anywhere books are sold, you'll find Aligned and thank you in advance for the support. Dr. Kristen Holmes on Instagram and LinkedIn. I write a lot. I also have a WordPress field notes on being human. I haven't come across this yet.

Yeah. I just started a couple of months ago. Each chapter begins with poetry and a lot of the poetry is lovely.

Oh, thank you. So the field notes, I'm quite a naturalist. So I have a field note each week and a writing each week, and it's either prose or poetry.

It's been leaning more toward the poetry as of late, but yeah, and sometimes the poetry, the writing will connect to the field note in some way, but the field notice is about something related to nature. It's been about birds mostly. So I'll kind of share a drawing and then I'll talk a little bit about the bird and I kind of bring in the science too and talk about the nervous system in some ways, but probably more less direct, less sciencey, a bit more lyrical, I suppose.

Yeah.

[ANGELA FOSTER] (1:01:56 - 1:02:03)
Amazing. And where is that? Field notes on being human.

Field notes on being human. We'll link to that in the description as well.

[DR KRISTEN HOLMES] (1:02:03 - 1:02:03)
Perfect.

[ANGELA FOSTER] (1:02:03 - 1:02:05)
That's amazing. I can't wait to read it.

[DR KRISTEN HOLMES] (1:02:05 - 1:02:06)
Thank you so much.

[ANGELA FOSTER] (1:02:07 - 1:02:08)
Thank you. I appreciate this so much.

She more than doubled her HRV in under a decade, and the behaviour that moved it most was not training, supplements or sleep duration, but going to bed and waking at the same time.

This week I sat down with Global Head of Human Performance at WHOOP and author of Aligned, Dr Kristen Holmes, to unpack why sleep-wake consistency is the foundation of a resilient nervous system in midlife.

WHAT YOU WILL LEARN

- Why is sleep-wake consistency a stronger predictor of mortality and disease than how long you sleep?

- How does the contrast between your day and your night affect the severity of menopause symptoms?

- What is the physiological sigh, and why did it outperform other anxiety-reducing techniques in the research?

- Can you really raise your HRV, and how much of it is genetic rather than modifiable?

- Why does eating late at night suppress both sleep quality and overnight recovery?

- Why do unresolved trauma and an outcome-driven identity keep your nervous system stuck in fight or flight?