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Comment by joshgel | Hacker News Reader

Exercising (moderate physical activity) for 2-2.5 hours per week leads to a 20% reduction in all-cause mortality (not to mention its many other benefits). Exercising for an additional 5.5 hours leads to another 20% reduction.

No preventative intervention we have in medicine leads to that kind of gains (except maybe quiting smoking).

Articles like this are probably causing harm to the people that read them by discouraging them from exercise [conjecture]. Until I see rigorous mortality data on taking bath, I think I'll stick to my exercise routine...

Source: https://www.cdc.gov/physicalactivity/resources/recommendatio... (see 2008 Physical Activity Guidelines Advisory Committee Report [PDF - 4.5MB])

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> Exercising (moderate physical activity) for 2-2.5 hours per week leads to a 20% reduction in all-cause mortality (not to mention its many other benefits). Exercising for an additional 5.5 hours leads to another 20% reduction.

With a very important caveat in the report:

> Because all of the studies in the evidence base were observational epidemiologic studies with no randomized controlled trials, the data cannot prove causality of effect.

People who don't feel that great when they exercise (despite everyone urging them to exercise) are probably not in the best health. The pervasive advice to exercise more will by itself confound the studies, because healthier people will tend to self-select into the "exercise" group.

Yeah, it has its weaknesses and also from my comment below: "So I read the study for fun and the non-adjusted rates are 3.84% death rate (cohort study) in no exercise vs. 2.35% in 1-30 minutes and 2.08% in more. And that's not adjusted for pre-existing conditions if I understood correctly. So meh. Even though 20% and 20% sounds really great!"

I didn't find anything there for longer periods of time but odds ratio is not a great indicator if your base chance of dying is already really low. Or maybe spend the whole week exercising to squeeze that last 0.1% out of your chance of dying.

3.84% to 2.08% is a 45% reduction in the amount of people that died. I don't understand your point, there is no obfuscation here, that's just how percentages work.

Um, no. 3.84% to 2.08% being an approx 40% reduction is exactly what is being avoided currently in research since its reduction of less than 2 percentage units. Imagine a medication that has a "20% and 40% reduction in mortality": You'd have to have more than 150 people treated to the max to save one person vs other cases (more than 75 to save vs no medication). Not 5 as your percentage implies. Not very efficient way to spend money if you ask me.

(3.84 - 2.08) / 3.84 = 45% less people dead

It's not 'my' percentage, nor subjective.

I mean you could argue the study is biased or the sample size too small, but your understanding of percentages seems flawed.

I recommend you take basic university statistics. Especially study efficacy vs effectiveness so you might have an idea how you're being mislead here.

I agree with your comments entirely. I'll also add, however, that even though this is cohort data 1) there is A LOT of data, almost all of it in agreement for hundreds and hundreds of studies, over millions of person years and 2) there is pretty strong evidence of a dose-response relationship. Both of those two points help (though don't entirely eliminate) the weaknesses inherent in cohort data.

It doesn't change the fact that if you take approx 150 from each of the activity groups, the cohort study will tell:

Approximately 5 from the "slobs" will die.

Approximately 4 from the "moderate exercise group" will die.

Approximately 3 from the "forrest gump group" will die.

On a personal level, to me these groups are more or less the same in terms of mortality, but somebody marketed the 20% really well.

Well if you truly don't understand math, please transfer 20% of your wealth to me. I mean, from your perspective it's the same amount of wealth, right?

that's not the point, the posters point is that the way the math was used added dramatic effect, it did not aid in understanding the meaning of the findings.

Exactly. 20% or 40% sounds really big. In reality, you're maybe lowering your chance to die (during some time) by less than 2% by exercising almost constantly. Now, if you're not enjoying exercise, or feel exhausted after exercising, you actually reduce the amount of "quality life" by exercising.

If exercise was a drug, they'd never allow it on the market.

In real world terms, holding on to the banister when going up and down stairs and sitting down when putting on your trousers on are real life extenders :)

This is the correct answer. Mobility is more important than exercise. You'll lose mobility by breaking bones.

> If exercise was a drug, they'd never allow it on the market.

Plenty of drugs have much worse efficacy and "numbers needed to treat" figures than exercise.

Current exercise advice is about 30 minutes per session with 3 sessions a week.

Not really. Take your 30 minutes of exercise per week that will reduce the chance of dying by 1% (2% is for the forrest gumps). Let's say you can do that by spending 60 minutes a day (changing clothes, getting dressed / undressed, showered and so on). In a 52-week year that will amount to loss of 156 hours of your life. For 8-hour work days that's 19.5 workdays. A good vacation's worth! No drug is allowed to do that.

And if you break your ankle or break your wrist or elbow when exercising, it'll never be as good as new.

What a silly set of arguments. Exercise is literally empty time for you with no other benefit? Lets put aside the fact that you receive endorphin from almost any exercise you do. You can't go to the beach, rock climb, play with your kids/dog, etc.? No, must be productive all the time. Even if that was the case, it's quality adjusted lifespan that counts for most people.

You may break your wrist sure. In the same way that you may get wrist injury from typing too much. Exercise will reduce the likelihood of other injury.

Ugh, your comment is so stupid I can't even be bothered to think of a proper reply.

I understand your point, while not detracting from the benefits of exercise, eating well, having moments of calm, etc,etc, these studies when reduced to a personal level become nonsensical, while one can make choices that at a 'group' level might suggest cause and effect, when the sample size is one, and it's you, the 'odds' are of little consequence, what is happening to you is the reality, knowing some malaise is is common, rare, or influenced by some life factors has no bearing...

There are are plenty of well understood mechanisms for how exercise can improve health. There are way may plausible but not yet well understood ways it can help.

Clearly any error from the self selection you described does not counter an demonstrable mechanism.

What if the study compared bedridden 100-year-olds as non-exercisers to the college track team? The track team was 20% less likely to die in the subsequent 10 years...

Self-selection can completely override other well-understood mechanisms...

These studies are usually done as cohort studies. Meaning the study group shares a defining trait (such as the same date of birth).

Obviously this is not as great as a double-blind study. But you can't let one group do real exercise and the other one placebo exercise. So the cohort study is probably the best possible study design in this case.

The people doing these studies try very hard to minimize biases (sometimes failing, but ruling out every possible biases is hard).

This.

And even your willing to exercise changes during live. It was easier and fun to exercise when was a teenager and so on. Become lot less when gained almost 40 pounds in a month due to medication. Become even less interesting when would get hurt for exercising while overweight. Become a no-go when got a muscle strain for simply going downstairs because a physiotherapist pushed a bit too much and was under muscular fatigue.

I'd prefer to take a bath and have some benefits that fell all that pain again and immobilize my leg and loose what I've earned in the past 4 months.

For those who already like to exercise (or are willing to despite saying "I don't like, just like the benefits", or any kind of wording of this idea), well, this study won't make a difference.

For me, yes, it makes.

This is exactly why I can't trust prescriptive conclusions from correlation studies. Didn't Google publish some method on resolving causation in correlation? Something about transfer of noise?

As somebody that exercises a lot (HIIT, cycling up hills, double black diamond skiing, tennis, lifting), I find longer stays in saunas/spas (>1h in "hot" overall, <15min/hot session, 1min/cold session) very beneficial as well, giving me a great feeling of well-being and clear mind, especially in winter (combined with D + Magnesium etc.), so I wouldn't be surprised if it had a positive long-term effect as well. I also look 15 years younger I am told, but that might be partially from being an electronic music composer ;-)

what do you take magnesium for?

My doc told me to always take magnesium if I take vitamin D.

I've just found an article about why to do it:

http://www.easy-immune-health.com/magnesium-and-vitamin-d.ht...

Seems like magnesium is needed to convert D to its active form.

Are you sure it is not for post mdma effects ? :)

Funny my nephrologist hasn't mentioned it I have kidney failure and take 4x250ng D 3 times a week,

Fascinating. Maybe I'm misinterpreting your units, but I have no related health condition (other than living in Canada), and I take 3x1000 every day (in months with an R in them).

Maybe you're somewhere particularly sunny?

Stage 4/5 Kidney failure will do that unfortunately - it messes with your biochemistry.

ng? as in nanograms? 1000 nanogram = 1 microgram (mcg), 40 IU = 1 mcg.

I take 5000 IU a day, or 125 mcg.

That website smells hokum to me. The prominent ads for magnesium supplements on that page are disconcerting, as are several references to "Dr. So-and-So" with no links to anything even pretending to be peer-reviewed articles. (Actually the "About Me" page is pretty much a flashing red neon sign when you go to it).

But even discounting that, the claim that magnesium is "used up" converting Vitamin D sounds, well, wrong. The closest thing I can find to a need to convert vitamin D into an "active form" is the conversion of cholecalciferol to calcidiol and thence calcitriol. The relevant enzymes all seem to be heme cofactors using iron in the heme, not magnesium. I also don't see any peer-reviewed articles looking at magnesium impacts on vitamin D uptake. There's a few old ones (~1991, with some even earlier) that suggest that vitamin D might affect magnesium intake.

It might be that magnesium is associated with the vitamin D precursor enzymes, since magnesium is a fairly widespread inhibitor of certain enzymes (in particular, it looks like it impacts parathyroid hormone, which is also impacted by Ca²⁺ ions in the normal case of action for vitamin D). But if that's the case, it's not that magnesium is being "used up" by vitamin D but rather you need a certain amount of it in your bloodstream to keep your calcium metabolism working.

If I'm reading https://examine.com/supplements/magnesium/ correctly:

Vitamin D is currently the only Essential Vitamin or Mineral which appears to have deficiency rates at a similar level to Magnesium, if not greater. The metabolism of Vitamin D inherently is linked to Magnesium. Magnesium levels in the brain can be negatively regulated by an excess of parathyroid hormone (PTH), where PTH causes release of calcium into the blood (being met with an increase of magnesium to retain homeostasis) possibly being a contributing factor to chronic depletion of magnesium concentration in neural tissue. As vitamin D reliably suppresses excess PTH, it may exert neural benefits secondary to preservation of Magnesium levels in the brain.

A Vitamin D deficiency could lead to magnesium depletion (Vitamin D deficency allows excess PTH, releases calcium, depletes magnesium). So in fact, the opposite is the case right? At sufficient Vitamin D levels you shouldn't have to supplement magnesium, assuming no dietary deficiency of it. Right?

As I'm reading the data... it sounds like like low vitamin D makes it harder to get enough magnesium, but high vitamin D has no effect on magnesium levels and (high or low) magnesium has no effect on vitamin D levels.

So the recommendation for vitamin D+magnesium would basically be "we think you've got low both if you've got low vitamin D, so just take both of them," relying on kidney functions to fix anything you've got too much of.

TIL Americans call red slopes "black diamond" and black slopes "double black diamond". Dunno why, but it's just really funny to me as a Scandinavian. (By nature of my origin I obviously also enjoy the sauna.)

Technically this depends on a resort - in Aspen or Squaw Valley a double black diamond is in the "insane" level category, much steeper/challenging than even the black FIS slope in Sölden. I remember the lift sign in Squaw Valley's Headwall/Palisades - "Experts only. No easy way down.", and it was like that. Maybe upper part of Hahnenkamm could be comparable ;-) Usually double black diamond corresponds to European free ride zones near steep ridges.

Of course. Trail ratings in North America are relative to each resort. I've gone down blues in the west that are far more challenging than the double blacks at a few areas in New England.

What does being an EDM composer have to do with looking young? Would be more inclined to associate it with MDMA and other drugs that would wear the body down.

Look at Armin van Buuren, Darude, Jean Michel Jarre etc. For some reason there are many music producers/DJs in their 30s-60s that look way younger than they should ;-) I don't remember who was that but one DJ that was ~42 looked like 18 (non-asian) and everybody was freaking out (I'll try to find that pic somewhere). Maybe this type of music energy activates something in the brain, who knows?

Kind of a nitpick, but electronic != EDM.

I assumed that the meaning here was "people see the way I dress and assume I'm 15 years younger." I expect that anyone frequenting the EDM scene is dressing the part.

This 2015 study on sauna use seems to point to something going on. There's a lot of speculation about whether heat shock proteins play a similar role in both hyperthermic conditioning and exercise (perhaps a form of hyperthermic conditioning in its own right). Scientists sometimes refer to sauna as "exercise mimicking".

https://www.sciencedaily.com/releases/2015/02/150223122602.h...

> For all-cause mortality, sauna bathing 2 to 3 times per week was associated with a 24 percent lower risk and 4 to 7 times per week with a 40 percent reduction in risk compared to only one sauna session per week.

I got the reference from Rhonda Patrick who did a summary of this any other research here:

https://www.youtube.com/watch?v=eWKBsh7YTXQ

A combination of exercise and heat-stress is almost certainly best, but there is probably significant overlap in effect.

I'm wondering how good/bad the combination is (think"hot yoga"), or if too much stress on cells/heart is simply too much.

It's a good question. I've seen some studies that show better recovery from exercise if it is followed by a steam or sauna. I don't think we know enough to determine what the dose-response curve looks like.

Related: the science is far from complete on cold exposure, but cryotherapy (cold air or ice baths) seems to enhance recovery for endurance training, but it strangely reduces progress in strength training, at least if it is done immediately following exercise. There is speculation that cold exposure reduces the post-exercise inflammation response enough to limit the body's repair response. This might not be the case if you do cold exposure outside of the post-exercise window (but this hasn't been studied afaik). Once again all credit to Rhonda Patrick who covers this in one of her videos on cryotherapy.

Actually 20% is dwarfed by other interventions. "Swedish study demonstrated that over a 20- year period, women who avoided the sun were TWICE AS LIKELY TO DIE OF ANY CAUSE, as women who were sun-seekers" referring to:

Lindqvist PG, Epstein E, Nielsen K, Landin-Olsson M, Ingvar C, Olsson H. Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort. J Intern Med. 2016 Oct;280(4):375-87

Lindqvist PG, Epstein E, Landin-Olsson M, Ingvar C, Nielsen K, Stenbeck M, Olsson H. Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort. J Intern Med. 2014 Jul;276(1):77-86

but couldn't that be because people who are more stressed are more likely to be photosensitive? Photo-phobia is a symptom of many severe diseases...

Stress and MCAS often do correlate with photosensitivity, and if you have MCAS all your allergy-like reactions are going to be increased by stress, true. I've found that if my exposure to sunlight is very regular I do pretty well, though. Of course, if stress leads you to take tricyclics, they can cause photosensitivity as well. I would not discount the possibility that regular sun exposure reduces stress by boosting the immune system (not just by Vitamin D) however: https://www.labroots.com/trending/health-and-medicine/4846/b...

Anyone who believes they can bathe instead of exercise is probably not exercising to begin with. I doubt this study would result in reduced exercise. But I could be wrong.

It does help to perpetuate a myth that there are alternatives to exercise which could enter in to a persons decision to exercise or not, even if they decide to do something else with their time.

Every generation has to create its effort-free alternative to exercise, whether it's electrodes you attach to your abs or standing there while a vibrating belt shakes your body.

Even George Jetson would sit around while the computer exercised for him, so I guess we know what's coming in the future.

Crippling socialized medical costs as the obesity rate skyrockets. :-/

Healthy people are more expensive.

People who don't exercise simply die young (in their 50s and 60s) and people who are healthy can cling on for decades fully utilizing the range of expensive treatments.

Does this account for the additional value a longer life may bring to society? A healthy person could stay in the workforce longer for example.

We are out of jobs. Need to downsize the human race. post peak employment.

If the economy's failing to engage with everyone, the answer is a less dysfunctional economy, not death camps.

No not at all, just raw expense.

Source? My understanding is that particularly in the US, we can keep unhealthy people going for a very long time, for a lot of $$$.

My source was the freakonomics podcasts.

I would agree that a billionaire with predictable medical expenses will more options than a person in any sort of health and likely live longer. Most people in bad health don't have unlimited money thought (simply because most people don't have unlimited money).

Upvoted for gainz.

Also here is a good hyperthermic conditioning article Dr. Rhonda Patrick/Tim Ferriss put together http://tim.blog/2014/04/10/saunas-hyperthermic-conditioning-...

Increased endurance, increased muscle hypertrophy and positive brain effects.

> Articles like this are probably causing harm to the people that read them by discouraging them from exercise [conjecture]

I know people who gleefully say 'ice cream burns calories!' while scarfing down a huge portion of desert. It's thanks to these fantasy articles where doing something easy or damaging is the same as exercising or eating healthy.

If one assumes the article is false - but in any case I can assure you that excuses not to exercise aren't rare or hard to find. I'm using one right now!

> excuses not to exercise aren't rare or hard to find

I feel like many fad diets fit the bill here. It's easy to take something that is healthy for you (eating well) and sell it as an alternative to exercise, when the latter is complementary to the former.

Hot baths are effective, but mostly in conjunction with actual excersise as well (pros, especially ones who are involved in very heavy lifting, regular have hot/cold post-workout baths). This article is very sadly misleading.

I would be interested in any bibliography you can supply regarding this interaction, since I'm currently interested in interventions (including but not limited to heat) that affect extracellular bacterial populations; and this could contradict some other evidence. (There is of course a lot of literature on heat-related illness and deaths during sports and exercise - so much so that it makes it hard to search pubmed for articles concerning the interaction you've pointed to.)

I'm already not exercising, so adding a bath sounds like it would be better than nothing. But honestly, I doubt I'd have the willpower to go to the trouble of bathing for an hour each day either.

If you want to exercise I would suggest taking a fitness class like ripped. It's one hour long and you can modulate your intensity.

Put your tablet in a ziploc bag and it's easy to spend an hour in the tub.

I see something similar in every article about some % of marathon runners who have heart problems. So many people read that and say, "Glad I don't run at all."

Not sure you read the article, the last paragraph makes clear that they hope this will help people that are unable to exercise. I guess they are thinking of the elderly or similar.

Of course people will interpret it as they wish but this is interesting research, not "vaccines-cause-x" type of research. For those looking for excuses I'm sure they can find plenty of others already.

Exercise as a gain reminds me of indoor plumbing: Indoor plumbing is perhaps responsible for a larger gain in life expectancy and preventive health than almost any other medical innovation in the history of mankind (also conjecture ;) ).

>Articles like this are probably causing harm to the people that read them by discouraging them from exercise

That makes me wonder how much the 'red wine is good for you' study added to alcoholism.

With "research" like "a glass of red equals to 30 minutes of exercise" and "beer may be the best recovery drink after physical activity" I think I have my exercise program in place!

I really don't understand those numbers. Surely mortality is 100% regardless of exercise. How was the study designed?

So I read the study for fun and the non-adjusted rates are 3.84% death rate (cohort study) in no exercise vs. 2.35% in 1-30 minutes and 2.08% in more. And that's not adjusted for pre-existing conditions if I understood correctly. So meh. Even though 20% and 20% sounds really great!

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