Too many important missing details, so it is hard to assess the validity of the results. Generally, observational studies of this kind are hotbed for false alarms and false hopes. The difficulty is that on average the people who sleep well and are physically active are also the people who eat well, have higher incomes and better access to healthcare. So it is hard to isolate one factor as the most responsible for the observed outcomes (the problem of confounding). Also, even if the observed average effects are real, it is hard to predict how that would translate into an effect at the individual level because the effect may depend on age, gender, genes, frailty, environmental factors etc (the problem of effect modification or interaction). Finally, because no actual data is shown, we do not know reliable and reproducible the results are (the problem of random error). Be careful of drawing any conclusions from observational studies especially studies of unknown methods and no published results.
Edited for typos
DemocracyFTW2 3 days ago [-]
Thanks for this comment. A text like this should really be present whenever medical study results are presented on HN.
lm28469 3 days ago [-]
The thing is that you can apply that to virtually every study. There are just way too many variables to control for. Unless you have a few thousand of identical twins locked down in sterile rooms from birth you can't do much
drgo 20 hours ago [-]
yes...I do not trust the claims of any single observational study. Using observational studies is necessary to help understand a problem in preparation for well-conducted large randomized clinical trials (RCTs). Sometime RCTs are not ethical or feasible (like etiological studies of cancer), and then we need many observational studies in different settings and using different designs showing a large effect that cannot be explained by known or unknown confounders and supported by many experimental studies (e.g., in cells). And even then we accept the results on the principle that is better to be safe than sorry. Many observational studies claimed that HRT protect women from heart disease until the definitive trial was done and it was found HRT actually increases the risk of heart disease!! Hundreds of other examples exist of well-researched and widely accepted hypotheses that turned out to be false in RCTs. For every observational study that claims X causes Y, I could find one that claims that X protects against Y, that X has nothing to do with Y, that Y causes X, that there is no X and no Y.. etc. It is the Wild West of science.
nkurz 3 days ago [-]
You're not wrong. Almost all observational studies could be subject to confounders which if true would invalidate their claimed results. But you seem to be suggesting that just because science is hard we should accept the results of all these flawed studies at face value without further questioning.
The better conclusion is that we should be skeptical of almost all such studies, and always look closely at the data and methodology to see if a confounding effect might contradict the conclusion. We should only give weight to studies that stand up to such scrutiny, and even then we should realize their limitations.
4 days ago [-]
uoaei 3 days ago [-]
> The difficulty is that on average the people who sleep well and are physically active are also the people who eat well, have higher incomes and better access to healthcare
Truly effective causal studies are still in their infancy, relatively speaking, and are still prone to the same correlation//causation fallacies. For instance, it's no fun studying things that may be the root cause of those behaviors but is hard to quantify, like "go-getter-ness" or something similarly illegible to scientific methods. You don't really know the structure of the problem so you can't put useful priors on it and focus in toward a reasonable inference. It's much easier to run t-tests and ANOVA by writing a couple lines of R so that's where we've settled as a community.
drgo 20 hours ago [-]
This is a very important point. It sounds obvious that the proxy for something should be treated as if it was the thing, but research is a business and researchers are people subject to peer pressure and social desirability bias. So the proxy becomes the thing.
throwaway22032 4 days ago [-]
This is the point that is missed so often in discussions about physical fitness.
Hundreds of millions of people, if not more, have been brainwashed into considering spending 8 hours a day at a desk to be normal whilst 1 hour a day of relatively sedate exercise is somehow "too much", when in reality that's actually still very low.
rubicon33 4 days ago [-]
Born to move, paid to sit.
n4r9 3 days ago [-]
Although this is broadly true, I suspect that ancient humans (as well as those in modern hunter gatherer tribes) still spent a good deal of each day sitting. Whether it's by the fire in the evening or next to the river waiting for something to get caught in the nets.
There's a lot of talk about standing more, but I wonder if a key difference is the sitting posture. Humans are born with the ability to sit into a deep squat and stay there for protracted periods. Core muscles engaged, knees apart, hips hinged. In the modern world we lose this ability at some age - maybe between 5 and 10? - and become accustomed to sitting in chairs. Core muscles lax, knees together, hips unhinged. Even so-called "ergonomic" desk chairs do not really help much I think, since it comes down to whether the sitter is really trying to engage and flex particular muscles.
Since learning to squat with barbell many years ago, I sit very differently in desk chairs. Knees apart and seat low, and leaning slightly forward (no use of backrest) so it somewhat mimics a squat. It looks weird, but I've never cared much about looking to fit in.
I don't think you'd need a special desk. There are office chairs that supposedly cater for a variety of positions such as squatting and lotus.
Brajeshwar 4 days ago [-]
I feel happy that I now can start a scientifically backed mental model that I should sleep 8.3 hours, and work for 6 hours or less.
shermantanktop 4 days ago [-]
Followed by unhappiness comes when you can’t stick to it, followed by happiness when you realize it was stupid. Unfortunately some people never get to step 3.
Brajeshwar 4 days ago [-]
Ah! That phenomenon where you leave a problem as it is because you get anxious and procrastinate. Then, it began to solve on its own. I love those.
joelthelion 3 days ago [-]
We could totally design the world around that. For now, we just lack the will to do it.
4 days ago [-]
cko 4 days ago [-]
2.2 hours of moderate to vigorous activity per day?
Lifting only takes like 5 minutes of actual movement per day. Guess I need to go play some basketball because walking one hour a day plus calisthenics just won't cut it.
Broken_Hippo 3 days ago [-]
In general, this is going to include things like sweeping the floor, vacuuming, and walking a dog. Putting groceries away can be a moderate activity. You might have a job that covers it, too.
It doesn't need to be all at once nor does it need to be dedicated exercise. You probably get some of this in your week as it is. If it helps, the link lists a slew of moderate and vigorous activity.
Its a 15 minute walk there, 15 minute walk back. But I make the trip twice... they only do it once. So they get 15 minutes at a time.
IncreasePosts 4 days ago [-]
Half and half, but really - it depends how old the kids are. 110 steps/min might be 180 steps/min for a smaller kid.
Also, kids frequently play by sprinting and then relaxing, and then sprinting, relaxing, etc. It's only boring adults who do steady state cardio like a long walk.
detourdog 3 days ago [-]
As a child I would want to go somewhere that was often 2 miles away and for whatever reason a bicycle wasn't used. I didn't consider it cardio I considered getting somewhere.
uoaei 3 days ago [-]
> It's only boring adults who do steady state cardio
That's an interesting observation, I'd never noticed that but you're right. There was always something uncanny to me about high school teams for cross-country running but I could never put my finger on it.
mathgeek 3 days ago [-]
That’s partially the competitive aspect as well. High school is peak “everyone can find something to compete in” for a lot of communities. Before that sports are usually more about play and afterwards tend more to recreation or exercise. Again, just generalities.
semi-extrinsic 3 days ago [-]
British Bulldog is still played all the way down to kindergarten in Scandinavia. It's called "hawks and doves" or "all my children come home".
mewpmewp2 3 days ago [-]
They must be joking. There's cardio heavy trainings that kids do for hour and half and I did myself when I was younger...
Soccer, karate, judo, whatever.
isoprophlex 3 days ago [-]
You wish! 7 to 7, AM to PM non stop running activity. They'll be doing cardio anyway, whether we're walking to school or not.
henry2023 4 days ago [-]
And strong
naveen99 3 days ago [-]
Lifting time includes rest between sets, so you are probably at 2hrs already including the walking, calisthenics and lifting.
2.2 hrs lines up pretty well with surveys I have seen on r/fitness.
I just started doing about that much (half walking, half weights) 2 months ago, and the results are pretty amazing.
Fire-Dragon-DoL 2 days ago [-]
2.2 every day of the week is really a lot. I do 1 to 2 hours 5 days a week, but on the weekend I want to do whatever I want
jltsiren 4 days ago [-]
That feels intuitively right. Humans are not particularly strong, fast, or agile. But given enough time, we can outrun almost every other animal. If endurance is what we are good at, it makes sense that we need more physical activity than most animals.
louthy 3 days ago [-]
But there is a difference between need when it comes to endurance (so that we can tire an animal enough that we can catch it and eat it) and the need to benefit from the physiological effects of movement.
It isn’t a given that endurance exercise is good for us (I mean, it probably is, but no more good than any other form), it is a given that humans have good stamina because we needed to eat though, that’s surely the only real conclusion we can extract?
keybored 3 days ago [-]
Say you’re designing a four-legged, cross-country robot for reconnaissance, like I’m sure some militaries have. One thing that comes up is that all the joints need to be constantly lubricated by movement or else they will stiffen and become unusable. This turns out to not be a problem because the robot will be used for continual movement while it is in use. So there is no need to worry about it: it would be wasted effort. Same with our bodies. The potential downsides of being biomechanically completely immobile for hours at a time (something like a deep squat is not completely immobile) have not been an issue for most of history.
The way I (intuitively) understand it is that we’ve been selected through generations to deal with certain situations well. Like endurance running. But when we get thrown into novel in the evolutionary sense situations, all bets are off. And it turns out that things work worse. For perhaps all kinds of possible reasons: maybe the baseline metabolism that hunter-gatherers had 20,000 years just because of their exact kind of activity levels turned out to be optimal for all kinds of biological functions as a sort of side effect.[1]
Another potential example is sleeping. In my experience I feel better in my muscles after sleeping on a hard surface. If you try to lay on your side on the floor you will feel like you are either stretching or massaging your muscles, or both. And maybe this low-intensity impact on the muscles throughout the night is necessary for some biological process? Contrast that with memory foam mattresses. Now if we were “designed” intentionally (tens of thousands of years ago), the designer would not have to worry about the biological implications of our bodies staying almost still on a soft surface for hours at a time. The best we would have is the ground, ranging from a soft, grassy meadow to just hard and sandy.
It’s like our bodies are constantly are subjected to conditions that no process (evolution) ever had to deal with (on an evolutionary scale).
[1] Now it could be that if we both undershot and overshot this baseline we could get in trouble. But it seems hard for most people to overshoot for some reason.
lm28469 3 days ago [-]
You're fighting millions of years of evolution here, you're definitely more adapted to walk a few hours per day than to sit in front of a computer. Your entire body was designed for something we don't do anymore, which we replaced by things it was never design to withstand (lack of exercise, bad diets, bad posture, &c.)
detourdog 3 days ago [-]
I'm starting to think that mental health is the real issue in modern society. All the rewards described by exercise may be available through good mental health. I think we maybe to focused on the physical symptoms.
louthy 3 days ago [-]
I’m not fighting anything. You can’t prove that I need to walk more than two hours a day to stay healthy. You can’t prove that humans haven’t evolved, at all, over that period of 1 million years.
Saying that we need a minimum of two hours walking per day is not based in any kind of fact at all. It is entirely assumption.
Exercise, yes, exercise for two hours or more per day, who knows?
lm28469 3 days ago [-]
All I know is that I follow my rules and I'm healthier than 99% of people I meet
louthy 3 days ago [-]
> I'm healthier than 99% of people I meet
Sure. At least we now have a sample size of 1 to extrapolate from.
lm28469 3 days ago [-]
The sample size is the western world, and we're at 70% of obese/overweight so clearly seating on your ass all day long isn't good. The average american walks something like 3k steps per day and its their sole activity. The #1 death cause in the west is directly caused by lack of exercise. How can people be in such denial ? If you have a full time desk job there aren't enough time in a day for you to over exercise, every single second you'll spend doing anything other than seating/laying down will b an improvement
> You can't prove that ...
Dude, open your eyes, look around you, seeing 70%+ of people having a beer belly at 30 isn't normal, it isn't healthy, most people don't even hit the bare minimum recommendations, I don't need a mathematical proof, it's all here in front of us
tuatoru 4 days ago [-]
[flagged]
henry2023 4 days ago [-]
I’d be nice to know which wearable the subjects used during this study. I’d wear one just to have an accurate assessment of my own 24hrs
cinntaile 3 days ago [-]
"Thigh-worn activPAL" according to the methodology section of the actual study the article is based on.
You can find the company's website here, although they don't seem to sell to consumers. Price should be around $400-500 I'd guess, some study published the price from 2021 which was 348 usd apparently.
[0] https://www.palt.com/pals/
freitzkriesler2 4 days ago [-]
"moderate-to-vigorous physical activity time might seem a quite high, at more than 2 hours a day, we defined it as more than 100 steps per minute. This equates to a brisk walk."
The scale here made me laugh.
So does actually going to the gym to break a sweat make it extreme physical activity?
Swizec 4 days ago [-]
I feel like all these articles/research are written from an extreme American perspective where people never move unless it’s from the couch to the car. You basically can’t exist in a European (and many others) lifestyle without getting this much exercise every day.
freitzkriesler2 3 days ago [-]
Basically the "averages" are so paheticly sedentary and unhealthy that getting any physical activity puts you in the outlier.
kortilla 3 days ago [-]
Most people in Europe would not qualify. The standard getting around the city paces are not fast enough for the threshold defined in this paper.
OJFord 3 days ago [-]
It's right there in the comment above, 100 steps/minutes. Just over one and a half steps a second. It's not ambling around window shopping, but that's not really that brisk at all if you're going somewhere.
Dunedan 3 days ago [-]
Nothing prevents somebody in Europe to stay at home without significant exercising all day, especially now as a lot of jobs are work-from-home.
eastbound 3 days ago [-]
I live in an area in France where the car reigns, and if I don’t do conscious exercise every day, I can end up with fewer than 1000 steps a day: Bed to kitchen, to the car, to meetings, then back home.
naveen99 3 days ago [-]
Breaking a sweat puts you above zone 2, which is basically extreme even by athlete standards and they spend less than 20% of their training time actually sweating.
freitzkriesler2 3 days ago [-]
I don't know what athletes you're looking at that don't break a sweat training.
3 days ago [-]
gregwebs 3 days ago [-]
Seems like the wrong question if you believe in evolution. That is humans did not evolve to sit as we sit today. I am trying to regain my ankle mobility and be in a squat position more. We also didn’t evolve to stand still at a standup desk for hours.
jajko 3 days ago [-]
Completely agree. If I look at apes definitely more sitting than standing, which still tells next to nothing about what is best for humans.
We know the answer - all kinds of movement, every day, not too intense but tons of it and not some 30 minute effort mixed with 12 hours of sitting. And bodybuilding as such has really nothing with evolution or whats good long term, just fashion and chasing women / childhood issues.
__egb__ 3 days ago [-]
This is why I have such high hopes for AR for work. I can keep my job but still return to the hunter-gatherer lifestyle of my distant ancestors…only I would be hunting bugs and gathering requirements.
euroderf 3 days ago [-]
You'll be wanting JIRA Jungle (TM).
Izkata 3 days ago [-]
You must investigate trees and bushes to find new cases to work on
croes 3 days ago [-]
By that logic we shouldn't walk on two feet either. Our ancestors didn't evolve to.
Havoc 3 days ago [-]
4 hours of activity a day is a big ask for most I suspect.
lm28469 3 days ago [-]
If people walked even a single hour per day they'd be much better off. With a typical office job you can easily get literally 0 minute of activity in your day. A decent diet, one hour of walk every evening and 30min of heavy lifts every other day and you'll be the fittest person in the room 90% of the time, such a small price to pay
keybored 3 days ago [-]
> the fittest person in the room 90% of the time, such a small price to pay
Such a small price to pay for what? The median person has notoriously bad diet, bad exercise/movement habits, etc. so what does being in 90th percentile even tell you? And what does it tell you to be
> and I'm healthier than 99% of people I meet
Because apparently this just says that you are more fit than a seal with pneumonia in the middle of a desert.
It seems more natural to ask what concretely you will be able to do. Because if I just wanted to get the Xth percentile bragging rights—which a lot of fitness bizarrely boils down to, with all the health benefits just being eh—I would just hang out with my father’s friends more.
dzhiurgis 3 days ago [-]
> fittest person in the room 90% of the time
Shifting goalposts, just like x% of richest controlling y% of wealth.
alamortsubite 3 days ago [-]
The irony is the typical American devotes more time than that each day to driving and paying for their automobile [1], the same device that robs them of a ton of physical activity they'd otherwise get without ever really thinking about it.
I do all my work from bed, I'd say 99%. Remaining 1% is odd meetings.
Does that count as sleep?
akira2501 4 days ago [-]
I would think "time outside" vs "time inside" is more important than "standing" vs "sitting."
mathgeek 3 days ago [-]
I would assume that those spending equivalent time sitting or standing outside end up with more vitamin d, seasonal issues with sunburn/frostbite, and tend to get rained on more often.
henry2023 4 days ago [-]
You could make your own research and publish it. Actually the methodology of this one is pretty straightforward
akira2501 3 days ago [-]
The research already exists. In either case I don't believe any methodology could possibly reveal the "perfect mix for optimal health." The headline belies the problem I have with this type of nonsense being posted on HN.
Rendered at 16:35:12 GMT+0000 (Coordinated Universal Time) with Vercel.
The better conclusion is that we should be skeptical of almost all such studies, and always look closely at the data and methodology to see if a confounding effect might contradict the conclusion. We should only give weight to studies that stand up to such scrutiny, and even then we should realize their limitations.
Truly effective causal studies are still in their infancy, relatively speaking, and are still prone to the same correlation//causation fallacies. For instance, it's no fun studying things that may be the root cause of those behaviors but is hard to quantify, like "go-getter-ness" or something similarly illegible to scientific methods. You don't really know the structure of the problem so you can't put useful priors on it and focus in toward a reasonable inference. It's much easier to run t-tests and ANOVA by writing a couple lines of R so that's where we've settled as a community.
Hundreds of millions of people, if not more, have been brainwashed into considering spending 8 hours a day at a desk to be normal whilst 1 hour a day of relatively sedate exercise is somehow "too much", when in reality that's actually still very low.
There's a lot of talk about standing more, but I wonder if a key difference is the sitting posture. Humans are born with the ability to sit into a deep squat and stay there for protracted periods. Core muscles engaged, knees apart, hips hinged. In the modern world we lose this ability at some age - maybe between 5 and 10? - and become accustomed to sitting in chairs. Core muscles lax, knees together, hips unhinged. Even so-called "ergonomic" desk chairs do not really help much I think, since it comes down to whether the sitter is really trying to engage and flex particular muscles.
Since learning to squat with barbell many years ago, I sit very differently in desk chairs. Knees apart and seat low, and leaning slightly forward (no use of backrest) so it somewhat mimics a squat. It looks weird, but I've never cared much about looking to fit in.
Edit - after writing the above I thought I should Google around,it turns out some modern hunter gatherers spend as much as ten hours per day in relative inactivity: https://arstechnica.com/science/2020/03/modern-hunter-gather...
Lifting only takes like 5 minutes of actual movement per day. Guess I need to go play some basketball because walking one hour a day plus calisthenics just won't cut it.
It doesn't need to be all at once nor does it need to be dedicated exercise. You probably get some of this in your week as it is. If it helps, the link lists a slew of moderate and vigorous activity.
https://www.cdc.gov/nccdphp/dnpa/physical/pdf/pa_intensity_t...
Do kids still play running games at school? Football--uh, soccer? Tag? British bulldog[1]?
A half-hour walk each way should be negligible.
1. https://en.wikipedia.org/wiki/British_bulldog_(game)
Also, kids frequently play by sprinting and then relaxing, and then sprinting, relaxing, etc. It's only boring adults who do steady state cardio like a long walk.
That's an interesting observation, I'd never noticed that but you're right. There was always something uncanny to me about high school teams for cross-country running but I could never put my finger on it.
Soccer, karate, judo, whatever.
2.2 hrs lines up pretty well with surveys I have seen on r/fitness.
I just started doing about that much (half walking, half weights) 2 months ago, and the results are pretty amazing.
It isn’t a given that endurance exercise is good for us (I mean, it probably is, but no more good than any other form), it is a given that humans have good stamina because we needed to eat though, that’s surely the only real conclusion we can extract?
The way I (intuitively) understand it is that we’ve been selected through generations to deal with certain situations well. Like endurance running. But when we get thrown into novel in the evolutionary sense situations, all bets are off. And it turns out that things work worse. For perhaps all kinds of possible reasons: maybe the baseline metabolism that hunter-gatherers had 20,000 years just because of their exact kind of activity levels turned out to be optimal for all kinds of biological functions as a sort of side effect.[1]
Another potential example is sleeping. In my experience I feel better in my muscles after sleeping on a hard surface. If you try to lay on your side on the floor you will feel like you are either stretching or massaging your muscles, or both. And maybe this low-intensity impact on the muscles throughout the night is necessary for some biological process? Contrast that with memory foam mattresses. Now if we were “designed” intentionally (tens of thousands of years ago), the designer would not have to worry about the biological implications of our bodies staying almost still on a soft surface for hours at a time. The best we would have is the ground, ranging from a soft, grassy meadow to just hard and sandy.
It’s like our bodies are constantly are subjected to conditions that no process (evolution) ever had to deal with (on an evolutionary scale).
[1] Now it could be that if we both undershot and overshot this baseline we could get in trouble. But it seems hard for most people to overshoot for some reason.
Saying that we need a minimum of two hours walking per day is not based in any kind of fact at all. It is entirely assumption.
Exercise, yes, exercise for two hours or more per day, who knows?
Sure. At least we now have a sample size of 1 to extrapolate from.
> You can't prove that ...
Dude, open your eyes, look around you, seeing 70%+ of people having a beer belly at 30 isn't normal, it isn't healthy, most people don't even hit the bare minimum recommendations, I don't need a mathematical proof, it's all here in front of us
You can find the company's website here, although they don't seem to sell to consumers. Price should be around $400-500 I'd guess, some study published the price from 2021 which was 348 usd apparently. [0] https://www.palt.com/pals/
The scale here made me laugh. So does actually going to the gym to break a sweat make it extreme physical activity?
We know the answer - all kinds of movement, every day, not too intense but tons of it and not some 30 minute effort mixed with 12 hours of sitting. And bodybuilding as such has really nothing with evolution or whats good long term, just fashion and chasing women / childhood issues.
Such a small price to pay for what? The median person has notoriously bad diet, bad exercise/movement habits, etc. so what does being in 90th percentile even tell you? And what does it tell you to be
> and I'm healthier than 99% of people I meet
Because apparently this just says that you are more fit than a seal with pneumonia in the middle of a desert.
It seems more natural to ask what concretely you will be able to do. Because if I just wanted to get the Xth percentile bragging rights—which a lot of fitness bizarrely boils down to, with all the health benefits just being eh—I would just hang out with my father’s friends more.
Shifting goalposts, just like x% of richest controlling y% of wealth.
1: https://www.youtube.com/watch?v=mUJFptzkdh8
Does that count as sleep?