"Those with the highest risk of dying from cancer or heart disease during the study period were those with the worst quality sleep and who didn't meet the WHO recommended guidelines for exercise. That risk went down for people with poor quality sleep but who did meet the exercise guidelines."
"The study isn't enough to prove causation – that more activity causes the reduction in harms from poor sleep – and it's based on self-reporting rather than independent observations. That said, there's enough of a correlation here to interest scientists."
"For now it's not clear why more exercise might make up for poor sleep, as far as our health goes. It could be that the increased activity is counteracting inflammation, or reducing irregularities in glucose metabolism, suggest the researchers."
Further research is actionable. This is useful encouragement, because absence of correlation implies absence of causation, so this is an efficient way of eliminating one disproof early.
When the conclusion is, literally, that there is correlation between these two variables over which people have control, how can you say it's "meaningless"? It's some evidence of what seems like an obvious hypothesis: sleep is healthy and exercise is healthy; if you do more of one and less of the other it should even out in some manner. They looked at the data and saw that this appears to be the case.
The "correlation is not causation" crowd who show up in every scientific article being discussed is the worst kind of pseudo-intellectualism. The authors of the paper went out of their way to say it.
The 30 minutes my watch insists on are having an even better effect than I'd realized--or rather I now understand why I've been feeling so much better, despite poor sleep the last week or so.
Still trying to improve my sleep, but I've been getting to bed early--and then waking up early too.
At Marine Corps boot camp, and subsequently combat training, not enough sleep and plenty of exercise is the norm. I averaged somewhere around 5 hours a night, but never more than 7, and many times somewhere between 3 and 0. There wasn't a lot of pure exercise, but constant activity based exercise, and a lot of stress based exercise. I was mid 20s when I went through it, and had a couple of guys with me who had to get age waivers (30+). We all agreed it was the most alert we'd ever felt, and that when we slept, we slept hard and felt extremely well rested, even when sleeping on hard ground.
Since exiting I spent many years feeling lethargic and burnt out from work, until I started training for a marathon. Now I have that same feeling, that it doesn't matter how much I sleep, and my body just feels more alive. Exercise, especially aerobic and cardio vascular, does wonders for your health, if you have time to do it right.
I've had onset insomnia my whole life, I also workout a bunch. It's just a habit now.
I feel the exact same way, I've actually had nights where I've only caught 4 hours sleep, woke up and ran 5kms, hiked mountains, lifted weights, rode bikes and felt as good as new. I only feel good if I workout.
I've also had days where I've had 8 hours sleep, then sat around the house and I feel absolutely horrendous, usually, I end up going and doing some physical activity to feel better.
I've always wondered if we're going to one day find out that the 8 hours sleep thing was wrong and that it's physical exercise we truly need.
> I've always wondered if we're going to one day find out that the 8 hours sleep thing was wrong and that it's physical exercise we truly need.
Two comments on that: The 8 hours sleep is a population average. It is very unlikely that you will need 8 hours of sleep, very likely your body will need more or less, and this will change as you age. You might very well be a 6 hours type.
That would basically invalidate what we know from animals - they are most vulnerable when they sleep, so it's unlikely evolution mad a mistake given all animals sleep, even the ones that don't have brains.
If you’re going to die soon (from the listed conditions), wouldn’t you be less likely to workout (especially with poor sleep)? I read the article and didn’t see this addressed, but maybe the study did…
You do have to watch out for that. IIRC that effect was behind the widely-reported "one drink a day is measurably better for you than never drinking!" thing, which turned out to be wrong—chronically ill people are more likely to teetotal, for obvious reasons, and also way more likely to die young than a healthy, drinks-sometimes peer—the causality was backwards, healthy people are more likely to drink. If anything, the actual results emphasize just how extremely bad drinking more than very occasionally is for your health, given at what low levels it overwhelms that large selection bias.
[EDIT] IIRC it's also the mechanism behind the "people who walk slower have higher mortality rates" thing. It's because people who are already sick or feel bad walk slower, and people who are sick or feel bad are more likely to die, and that wasn't well-controlled-for, not because being a slower walker per se makes you more likely to die, at least not to such a high degree as was reported.
Some people do weigh-lifting before sleep as it gets them tired to drift into a bliss easily, but others say if they do the exercise they cannot sleep at all and they actually prefer to do it after sleep.
I wonder why such a drastic difference of experience between people?
How you do your lifting can have drastic effects on how pumped up or relaxed you are afterwards. Lifting can be meditative and slow and systematic and leave you tired without being agitated, or you can do the full "Rocky" thing and get all pumped up and adrenaline flowing and grunting like the Hulk, and come out of it not just unable to sleep but unable to sit still.
Could be other things as well, of course, but that strikes me as one factor that might well produce those different effects.
Yeah, exercise tires me out regardless, that's the core. The difference is whether I get amped up at the same time.
Ive found the biggest difference is how much I've used my body in the past few days - working out for the first time in a while leaves me energized no matter what time it is.
There may be a small number of people for whom strenuous exercise right before sleep doesn't interfere, but a more likely explanation in my mind is broscience. The weightlifting community is especially susceptible to training methodologies which are suboptimal but fit the identity they're performing. Are these people really scientifically evaluating the affect of intense exercise close to bedtime, or are they working backwards from what _feels_ the most "manly"?
Personally, the ideal time for me to lift is my serum caffeine peak, and when I'm done, it takes a half hour to 45 minutes for my heart rate to return to baseline. I'll sweat another 500ml or so during the refractory period, and have no appetite to speak of. I can't even imagine sleeping during this time.
After which my appetite returns with a vengeance, and I'm up for a big meal and a long nap if I can swing it. I sleep very well on lifting nights, which is a blessing because my sleep quality is unfortunately poor in general these days (you can skip the advice, I don't need or want it, thanks).
Lifting weights starting about three hours before bedtime might work, actually, but hasn't really been compatible with gym scheduling for me. I'm about to join one with later hours and might try it, although rallying after supper strikes me as unlikely given my usual energy levels. Worth a shot though!
I have a weird ancedote. I used to experience the same effect, but now that I've gotten to dangerously heavy weights (385 squats, 435 deadlift, etc...), I have stopped being able to go up in weight and sleep benefits have gone away.
I do various routines to push that number higher, but it's slow and most of the cycle I'm not at my heaviest weights.
Anyway, now I run and I get those benefits again.
Just weird how the benefits of weight lifting have slowed down with a half decade of experience..
I'm with you. I don't really push myself as a result. If I can do them safely I'm happy.
But as soon as stuff moves that isn't supposed to, I deload. I'm still able to knock out 315lb squats easy.
My original goal was to make thick bones and get muscle while I'm still young. If I can carry lifting into old age, I'm hoping to stay good sized and move around.
I did a lot of grinding out heavy reps when I was younger and less experienced(mid-30s now) but now I am suspicious of that whole idea. If I stick to two reps before failure - i.e. when I start really slowing down the movement - my recovery time post-workout becomes much better and I don't experience as much collapse-into-bed tiredness, but I'm still seeing progression. There's an old broscience debate about whether muscle damage is critical but my own observation is that if it is, you don't need a lot of it, and doing so would favor PED users with tons of recovery capacity.
I also shifted my focus away from the largest muscle groups towards hip/core/shoulders, under a similar reasoning that if what I'm up against is mostly recovery capacity, the small muscles can be trained safely at higher frequency and will have the most impact on injury prevention and avoiding the stoop, rounded shoulders, etc. that afflicts the old.
There is the concept of "hypermetabolic" where it is hard to sleep after sustained exercise essentially because your body is so fired up. I have experienced this, but it really has to be an unusually long run, at least 30km usually more. It would not surprise me that you're correct, and the threshold for this state varies by person (and almost certainly fitness level) so for some it could occur at low levels like you say.
I get something like this even from a relatively light exercise (~40 minutes of pilates reformer). If I do it after 6pm my body feels very hot and I have trouble sleeping even 5-6 hours later.
Evening exercise won't do anything and will probably make it worse, e.g., body thinks it needs to stay awake to party / dance / get some lovin. Evolutionary psych basis possibly?
I do find it does improve the quality of sleep, but I also find that I sleep more if I exercise. When I am exercising vigourusly six days a week, I am passing out at like 9 pm. I recently had some small surgery and couldn't exercise for a few weeks, and I found myself staying up super later and having trouble going to sleep. I just wasn't that tired.
I do a lot of weight lifting and indoor cycling, and they have helped me get high-quality sleep and have much more consistent days.
I think it would be hard to get both get a lot of exercise and not sleep much. Exercise improves sleep, and when you are sleep deprived, it is hard to get energy to exercise.
Another personal anecdote - if I do deadlifts on any given day, I need an hour extra sleep that night (or more accurately, I suffer in the morning from not having had it). Maybe that need fades with experience but its a major reason deadlifts don't feature prominently in my routine
I think this is why a lot of routines tapper down how much deadlifting you do as you get stronger, sometimes to once a week or once a month.
Professional football players don't deadlift, for instance. They do a lot power cleans and variations. Deadlifting can be very taxing (although it is one of my favorite exercises).
The 'Plenty' is very key here. I have friends who excercise a lot and are able to get by with less sleep but if you stop working out the need for sleep comes back real fast.
"We found those who had both the poorest sleep quality and who exercised the least were most at risk of death from heart disease, stroke, and cancer"
If we make the (strong) assumption that sleep is primarily a cognitive repair period, then maybe this isn't too surprising? It would be interesting to do the same study, but measuring cognitive ability instead of risk of death.
I hate to be a party pooper (actually, I don't), but if your sleep is poor, you need to look inside yourself and calm your mind down. In the long run, exercising a lot won't compensate. You want to enter another world, not keep processing the daytime world.
Turn your phone off, do only non-stressful things and don't eat before bed, cover up all clocks in your bedroom, and yes, meditate. That's how you sleep better.
I've found the opposite effect: on the days when I've exercised minimally, I tend to sleep poorer, not to mention feeling more stress when awake. On the days that I do exercise, my sleep is much better: falling asleep faster, not as easily awaken, etc.
It’s great that you’ve found things that work for you but you should avoid believing that these are universal truths. Our minds are complicated and varied and it seems implausible to think that there are solutions that fit everyone.
On the other hand all of what that commenter recommended has a tonne of evidence behind it, some of which was merely taken for granted as true at a time when our lifestyles weren't as buzzed-out or sedentary than they are now.
Looking inside of myself just makes me more restless. It's about the worst thing I can do if I actually want to sleep. Exercise has been a great help in shutting off my mind at night.
To the degree that folks have agency over their sleep schedule, yes, improving sleep is the best path to improving sleep.
For those of us that have less control over that situation (I'm a parent of young children; others may struggle with chronic illness or other interferences), more tools in the toolset are welcome.
Chronic insomnia is an actual medical condition, just like feeling low is distinct from depression.
Just like basically anyone with depression has tried most-to-all of the "if you're feeling down try this!" advice, those of us afflicted with insomnia have tried any "winding down" method you might casually inflict as low effort drive-by advice on the internet.
Yeah it works sometimes. Then some other times I just don't fall asleep that night and it messes up my whole week. So it goes.
Yeah, I know, but believe me, it's not drive-by advice just because you hear it all the time. Things can be true without being easy (or even possible for everyone).
Insomnia might be a medical condition, but that doesn't mean your doctor has a prescription for it. If they do, it probably comes with a bunch of advice similar to the conventional stuff you're tired of hearing.
I meditate regularly, and when I can't sleep, I meditate in bed until I do. It can take an hour, but almost always works; otherwise I can be up for much longer.
I'm currently going through pretty bad insomnia and sleeping medication withdrawal, so my sleep is absolute garbage (usually < 4 hours). However, every morning I wake up and run 20 to 30 minutes on a treadmill, and at night I go for long walks at a fast pace. Just had a checkup a couple weeks ago and my vitals are all good. My blood work is good as well.
I've averaged about 12-25km per week for the past 3 years, and have been doing about 34km in the past month.
My sleep is not "better" just cause I exercise. I sleep like normal. I go in spurts of 6 hours of sleep when I'm under stress from like work or life and I never feel rested. I often have 30 minute uncontroable powernaps that I have to entertain once or twice a day. If not I do that head bobbing thing.
When I get at least 7:30-8 hours of sleep I don't have that issue. I can function on 6 but I don't feel better at 6. So take this study with a grain of salt. Your probably alert because you have other issues your brain is concerned about as opposed to actually being relaxed. I can function on 4 hours of sleep too. Running a 10k though isn't going to make the day any easier and offset be having another 4 hours of sleep for the day.
Exercise isn't some sort of panacea for poor sleep. It's much more likely tied to the fact that people who exercise live regimented lifestyles so their circadian rhythm is more in tune with the time of day than the amount of sleep.
This would certainly explain why I feel great during the winter (aka ski season) and like absolute shit during the summer (when I spend 99% of my waking hours in a chair or on the couch), despite equally terrible sleep habits year-round.
Unfortunately skiing has spoiled me in that if I fall, I like having a decent chance of falling into something soft.
Additionally, skiing is much more fun than rollerblading, to the point that if I had to miss an entire ski season due to some silly rollerblading (or mountain biking, which is what most everyone else around here does, or whatever) injury, I'd never forgive myself.
Worse than missing one or more ski seasons? I actually don't think so, although I will allow the possibility that I'm actually insane.
What I probably need is some sort of in-home exercise machine, or maybe just going to the local gym. Last year both of those things were a bit hard to come by, I don't know why I'm still sleeping on it this year though. In fact I'm going to go look into this right now lol
You are both right, of course. I just haven't learned how to force myself to be active during the summer, because the other half of the year, I don't have to do anything of the sort.
You just need to find something that works for you - there are certainly lots of physical activities that are pretty low injury (hiking, swimming, yoga, etc).
That's what everyone else does around here, but I just don't get it. Why would I want to risk losing a ski season for something way less fun in the first place? Not even to mention how expensive the bikes are.
You are allowed to disagree :) Personally I'd rate mountain biking as a moderately fun activity, not even close to being worth breaking bones for. Skiing on the other hand is 10x better than sex and cocaine combined.
Ha ha where in the world are you skiing that it's that much fun? I love skiing too I just love mtb more. I'm just trying to say sitting around for more than half the year so you don't get hurt for ski season seems like a giant unecessary waste.
fwiw I've never gotten injured enough from mtb to miss a ski season. You can definitely tone down your mtb'ing to x-country or something less extreme.
If not at least take up something like hiking or running in the warmer months. It'll make your ski season much more enjoyable if you're in shape when it starts.
I do enjoy hiking but not to the point of waking up at 6am to do it 4-5x a week. I do a few every year, including some relatively intense ones -- there's one near here that has over 4k ft gain in just 3.5 miles.
Curiously, I have no issues whatsoever waking up before dawn during ski season...
> For now it's not clear why more exercise might make up for poor sleep
One potential reason is dramatically lower cardio stress. I run about 3-4 miles 4-5 times a week through asthma. I can run through the asthma for a bit but it raises my pulse rate during exercise. Even better than running is long distance speed walking which burns calories just the same but keeps your pulse in your exercise target heart rate. The result is a resting heart rate of about 53 bpm for most of the rest of the day with excellent blood pressure. A couple years ago when I was fast (and far away from my asthma triggers) my resting heart rate was around 44bpm. Not bad for somebody in their 40s.
Out of shape my resting heart rate is closer to low or mid 70s and my blood pressure is about 40 points higher. I also seem to achieve 20 pounds overweight. My heart has to work much harder during the day and I need better sleep to make up the difference.
As a side note I have discovered the muscles that induce asthmatic symptoms fall off after about 45 minutes of continuous intense cardio. I suspect that’s how long it takes for those muscles to reach muscle failure and relax.
Sleep involves large-scale slow rhythmic synchrony of the brain — a kind of low information entropy state because of the high degree of coherence. Despite the heat, running also involves a large-scale slow rhythmic synchrony of the body and brain. Hypothetically, high-coherence exercise might have similar cognitive effects as sleep.
This is a testable hypothesis. Simply compare low-coherence exercise (say, moving boxes or frenetic dance) with high-coherence exercise (running or rowing).
Subjectively, I appreciate my running routine because it's so meditative. I obviously can't say what the brain waves might look like, but there are so many physical cadences that create a nice synchrony: heart beats, steps, breaths.
Side comment, on the subject of sleep, exercise and plenty more, I strongly recommend checking Huberman Lab podcast [0]. Also, I have no connection to him, other than being a listener who found the information useful.
87 comments
[ 0.21 ms ] story [ 132 ms ] thread"Those with the highest risk of dying from cancer or heart disease during the study period were those with the worst quality sleep and who didn't meet the WHO recommended guidelines for exercise. That risk went down for people with poor quality sleep but who did meet the exercise guidelines."
"The study isn't enough to prove causation – that more activity causes the reduction in harms from poor sleep – and it's based on self-reporting rather than independent observations. That said, there's enough of a correlation here to interest scientists."
"For now it's not clear why more exercise might make up for poor sleep, as far as our health goes. It could be that the increased activity is counteracting inflammation, or reducing irregularities in glucose metabolism, suggest the researchers."
Those quotes belie the truth--the article and any inferred conclusions therefrom are meaningless.
The "correlation is not causation" crowd who show up in every scientific article being discussed is the worst kind of pseudo-intellectualism. The authors of the paper went out of their way to say it.
2/3rds of the way through.
I'm glad myself and others point this out. I personally read the whole article.
That's time I can't get back. In the interest of keeping HN content worthwhile, people can and should point this sort of thing out.
Plus, the title isn't exercise and sleep correlate with health. The title implies causation.
Still trying to improve my sleep, but I've been getting to bed early--and then waking up early too.
At Marine Corps boot camp, and subsequently combat training, not enough sleep and plenty of exercise is the norm. I averaged somewhere around 5 hours a night, but never more than 7, and many times somewhere between 3 and 0. There wasn't a lot of pure exercise, but constant activity based exercise, and a lot of stress based exercise. I was mid 20s when I went through it, and had a couple of guys with me who had to get age waivers (30+). We all agreed it was the most alert we'd ever felt, and that when we slept, we slept hard and felt extremely well rested, even when sleeping on hard ground.
Since exiting I spent many years feeling lethargic and burnt out from work, until I started training for a marathon. Now I have that same feeling, that it doesn't matter how much I sleep, and my body just feels more alive. Exercise, especially aerobic and cardio vascular, does wonders for your health, if you have time to do it right.
I feel the exact same way, I've actually had nights where I've only caught 4 hours sleep, woke up and ran 5kms, hiked mountains, lifted weights, rode bikes and felt as good as new. I only feel good if I workout.
I've also had days where I've had 8 hours sleep, then sat around the house and I feel absolutely horrendous, usually, I end up going and doing some physical activity to feel better.
I've always wondered if we're going to one day find out that the 8 hours sleep thing was wrong and that it's physical exercise we truly need.
Two comments on that: The 8 hours sleep is a population average. It is very unlikely that you will need 8 hours of sleep, very likely your body will need more or less, and this will change as you age. You might very well be a 6 hours type. That would basically invalidate what we know from animals - they are most vulnerable when they sleep, so it's unlikely evolution mad a mistake given all animals sleep, even the ones that don't have brains.
It's jut exercise saves me. At least it feels like it does.
[EDIT] IIRC it's also the mechanism behind the "people who walk slower have higher mortality rates" thing. It's because people who are already sick or feel bad walk slower, and people who are sick or feel bad are more likely to die, and that wasn't well-controlled-for, not because being a slower walker per se makes you more likely to die, at least not to such a high degree as was reported.
Could be other things as well, of course, but that strikes me as one factor that might well produce those different effects.
Ive found the biggest difference is how much I've used my body in the past few days - working out for the first time in a while leaves me energized no matter what time it is.
Personally, the ideal time for me to lift is my serum caffeine peak, and when I'm done, it takes a half hour to 45 minutes for my heart rate to return to baseline. I'll sweat another 500ml or so during the refractory period, and have no appetite to speak of. I can't even imagine sleeping during this time.
After which my appetite returns with a vengeance, and I'm up for a big meal and a long nap if I can swing it. I sleep very well on lifting nights, which is a blessing because my sleep quality is unfortunately poor in general these days (you can skip the advice, I don't need or want it, thanks).
Lifting weights starting about three hours before bedtime might work, actually, but hasn't really been compatible with gym scheduling for me. I'm about to join one with later hours and might try it, although rallying after supper strikes me as unlikely given my usual energy levels. Worth a shot though!
I do various routines to push that number higher, but it's slow and most of the cycle I'm not at my heaviest weights.
Anyway, now I run and I get those benefits again.
Just weird how the benefits of weight lifting have slowed down with a half decade of experience..
Is there some trade-off to be gained vs. the long term risk or injury?
But as soon as stuff moves that isn't supposed to, I deload. I'm still able to knock out 315lb squats easy.
My original goal was to make thick bones and get muscle while I'm still young. If I can carry lifting into old age, I'm hoping to stay good sized and move around.
Plus all the health benefits until then.
I also shifted my focus away from the largest muscle groups towards hip/core/shoulders, under a similar reasoning that if what I'm up against is mostly recovery capacity, the small muscles can be trained safely at higher frequency and will have the most impact on injury prevention and avoiding the stoop, rounded shoulders, etc. that afflicts the old.
Evening exercise won't do anything and will probably make it worse, e.g., body thinks it needs to stay awake to party / dance / get some lovin. Evolutionary psych basis possibly?
PE recalibrate a lot of things in me, I sleep earlier, fall asleep faster, goes deeper.
I do a lot of weight lifting and indoor cycling, and they have helped me get high-quality sleep and have much more consistent days.
I think it would be hard to get both get a lot of exercise and not sleep much. Exercise improves sleep, and when you are sleep deprived, it is hard to get energy to exercise.
Professional football players don't deadlift, for instance. They do a lot power cleans and variations. Deadlifting can be very taxing (although it is one of my favorite exercises).
Military, school, work, life in general. Keep those three going, and you are operating at peak performance.
If we make the (strong) assumption that sleep is primarily a cognitive repair period, then maybe this isn't too surprising? It would be interesting to do the same study, but measuring cognitive ability instead of risk of death.
Turn your phone off, do only non-stressful things and don't eat before bed, cover up all clocks in your bedroom, and yes, meditate. That's how you sleep better.
Of course people will disagree. Some have. Good for them.
For those of us that have less control over that situation (I'm a parent of young children; others may struggle with chronic illness or other interferences), more tools in the toolset are welcome.
My thoughts never stop.
Just like basically anyone with depression has tried most-to-all of the "if you're feeling down try this!" advice, those of us afflicted with insomnia have tried any "winding down" method you might casually inflict as low effort drive-by advice on the internet.
Yeah it works sometimes. Then some other times I just don't fall asleep that night and it messes up my whole week. So it goes.
Insomnia might be a medical condition, but that doesn't mean your doctor has a prescription for it. If they do, it probably comes with a bunch of advice similar to the conventional stuff you're tired of hearing.
My sleep is not "better" just cause I exercise. I sleep like normal. I go in spurts of 6 hours of sleep when I'm under stress from like work or life and I never feel rested. I often have 30 minute uncontroable powernaps that I have to entertain once or twice a day. If not I do that head bobbing thing.
When I get at least 7:30-8 hours of sleep I don't have that issue. I can function on 6 but I don't feel better at 6. So take this study with a grain of salt. Your probably alert because you have other issues your brain is concerned about as opposed to actually being relaxed. I can function on 4 hours of sleep too. Running a 10k though isn't going to make the day any easier and offset be having another 4 hours of sleep for the day.
Exercise isn't some sort of panacea for poor sleep. It's much more likely tied to the fact that people who exercise live regimented lifestyles so their circadian rhythm is more in tune with the time of day than the amount of sleep.
Edit: k to km/week
The snow here in Northern Tasmania wasn’t real good so I only went up the hill once.
But we bought roller blades in the warmer months, and I go for a run in the morning before work.
Additionally, skiing is much more fun than rollerblading, to the point that if I had to miss an entire ski season due to some silly rollerblading (or mountain biking, which is what most everyone else around here does, or whatever) injury, I'd never forgive myself.
What I probably need is some sort of in-home exercise machine, or maybe just going to the local gym. Last year both of those things were a bit hard to come by, I don't know why I'm still sleeping on it this year though. In fact I'm going to go look into this right now lol
You don’t necessarily have to be inactive, that’s your choice ;)
Also I completely disagree with skiing being way more fun. There are way more areas you can take your mountain bike.
Equipment wise you're not paying much more for a bike than you do for all that ski equipment and you don't need to pay outrageous lift fees.
fwiw I've never gotten injured enough from mtb to miss a ski season. You can definitely tone down your mtb'ing to x-country or something less extreme.
If not at least take up something like hiking or running in the warmer months. It'll make your ski season much more enjoyable if you're in shape when it starts.
I do enjoy hiking but not to the point of waking up at 6am to do it 4-5x a week. I do a few every year, including some relatively intense ones -- there's one near here that has over 4k ft gain in just 3.5 miles.
Curiously, I have no issues whatsoever waking up before dawn during ski season...
One potential reason is dramatically lower cardio stress. I run about 3-4 miles 4-5 times a week through asthma. I can run through the asthma for a bit but it raises my pulse rate during exercise. Even better than running is long distance speed walking which burns calories just the same but keeps your pulse in your exercise target heart rate. The result is a resting heart rate of about 53 bpm for most of the rest of the day with excellent blood pressure. A couple years ago when I was fast (and far away from my asthma triggers) my resting heart rate was around 44bpm. Not bad for somebody in their 40s.
Out of shape my resting heart rate is closer to low or mid 70s and my blood pressure is about 40 points higher. I also seem to achieve 20 pounds overweight. My heart has to work much harder during the day and I need better sleep to make up the difference.
As a side note I have discovered the muscles that induce asthmatic symptoms fall off after about 45 minutes of continuous intense cardio. I suspect that’s how long it takes for those muscles to reach muscle failure and relax.
This is a testable hypothesis. Simply compare low-coherence exercise (say, moving boxes or frenetic dance) with high-coherence exercise (running or rowing).
Links:
[0]: https://hubermanlab.com