Does Exercise Slow the Aging Process? | Hacker News Reader

Does Exercise Slow the Aging Process?

well.blogs.nytimes.com

70 pointsprostoalex24 comments

Life-long spontaneous exercise does not prolong lifespan but improves health span in mice http://www.longevityandhealthspan.com/content/2/1/14

Dose of Jogging and Long-Term Mortality : The Copenhagen City Heart Study http://dx.doi.org/10.1016/j.jacc.2014.11.023

Working up a sweat -- it could save your life http://www.eurekalert.org/pub_releases/2015-04/jcu-wua040215...

Lack of exercise kills roughly as many as smoking, study says http://latimesblogs.latimes.com/world_now/2012/07/lack-of-ex...

Every Minute Of Exercise Could Lengthen Your Life Seven Minutes http://commonhealth.wbur.org/2013/03/minutes-exercise-longer...

And so on. There's a lot more out there on exercise and mortality risk as determined from large epidemiological data sets in humans or cause-and-effect animal studies if you care to go look around. One present focus is trying to pin down the dose-response curve, for example.

Telomere length, as measured in the study linked here, isn't worth paying much attention to. There are many, many problems with linking average telomere length in white blood cells to specific outcomes in aging. In many ways it is even more of a fuzzy number than, say, BMI or exercise level.

The copenhagen study is one that stays with me. Over a period of 35 years, and ~17000 people, there are some interesting charts showing guidelines to optimise jogging for longevity.

If I recall correctly, the best benefit was for joggers to run three times a week for 7 kilometers at 7 kilometers per hour. This would give an extra five years of life, and as the parameters (#times per week, distance, speed) veered from this benefits declined along a bell curve.

Interesting bit about 7 kilometers per hour. That's almost walking speed.

Hmm... that's 4.3 mph, or 4 miles in 56 minutes, or 14 minute miles. Not very fast at all.

Quoting my genetics professor:

"Exercise affects DNA repair systems. So moderate exercise speeds metabolism, which increases free radical production, which damages DNA, which activates DNA repair systems which catch the damage caused by the exercise and perhaps some additional damage as well - that's good and probably increases lifespan. Exercising too much creates more damage than the DNA repair systems can catch - which is bad, and explains why very fit people are often unhealthy. Exercising twice a week seems to be the optimum for most people."

"Very fit people are often unhealthy"

Is this even true? It doesn't seem true.

Everything is a tradeoff. About 10 to the 16 cell divisions occur in a typical lifespan so somewhere in cells that are part of you each of your genes has mutated 10 to the 10 times. Most mutations are neutral, some are beneficial and others can cause cancer.

Any activity that makes you sweat is likely causing damage to your cells which now have to replace lost material by dividing at a higher rate, increasing your chances of cancer and other diseases.

Source for the numbers: http://harpers.org/archive/2008/04/contagious-cancer/?single...

Rather than "mutations cause cancer", a better model is that mutations break genes that prevent cancer or ensure multi-cellular collaboration.

All cells have many defenses to prevent cancer, it's the systematic, uncaught erosion of these that leads to malignancy.

Literature reviews of over 54 studies say it's not true. Elite athletes live longer than average.

>Considerable support was found for superior longevity outcomes for elite athletes, particularly those in endurance and mixed sports

http://www.ncbi.nlm.nih.gov/pubmed/26301178 http://www.ncbi.nlm.nih.gov/pubmed/19574095

There may be confounding factors e.g. genetic factors, lifestyle, wealth, and status.

Top level sportsmen are not known to live very long, so I'd rather say this is probably true.

I don't see how that follows from "Very fit people are often unhealthy"

Ignoring the issue that (un)healthy is very hard to define, top level sportsmen could be fit and healthy up to moderate age, then drop dead.

Also, we have http://www.ncbi.nlm.nih.gov/pubmed/21618162 on Tour de France competitors:

"Our major finding is that repeated very intense exercise prolongs life span in well trained practitioners. Our findings underpin the importance of exercising without the fear that becoming exhausted might be bad for one's health."

and linked from there, a review paper (http://www.ncbi.nlm.nih.gov/pubmed/19574095):

"It appears that elite endurance (aerobic) athletes and mixed-sports (aerobic and anaerobic) athletes survive longer than the general population, as indicated by lower mortality and higher longevity. Lower cardiovascular disease mortality is likely the primary reason for their better survival rates. On the other hand, there are inconsistent results among studies of power (anaerobic) athletes"

There may be a lesson there for those advocating all kinds of muscle building exercises, but of course, there might be selection at work, too. Few people who are truly bad at endurance work will choose to compete in endurance sports for years, and it could be that those good at endurance sports have higher life expectancy, even if they don't do the training.

Can you give some examples? That sounds like some old wives tale to me.

Here is a fairly in-depth analysis of the excessive running issue that made rounds through the press last year.

Must be read critically, particularly the argument about confounding factors, but it does a good job of introducing the various findings, actual data, and arguments from both sides of the issue.

In any case, when it comes to running, the consensus is that there are diminishing, eventually negative, returns.

http://www.runnersworld.com/sweat-science/will-running-too-m...

Eating clen and trenning hard does seem to negatively affect health of a person. And there is hardly any top athlete that has not taken such stimulants.

How do they know that the relationship isn't the inverse: people with slower telomerase reduction age more gracefully and are more likely to report being physically active because they have developed fewer disabilities? Their "critical window" (40-65) also lines up suspiciously well with when people's bodies start to get creaky.

There are studies which can look at this, if you can do long-term longitudinal studies.

Taking two otherwise identical populations, particularly identical twin populations, and looking at how they respond to a regime of exercise vs. one without might work. The duration of such studies (years to decades) makes them exceptionally difficult and expensive to carry out. And, of course, you don't get results for ages.

One of the more famous of these is the Framhingham Heart Study, begun in 1948, and now on its third generation of participants. The original study included over 5,200 participants: https://en.wikipedia.org/wiki/Framingham_Heart_Study

They don't. From the article:

"However, as Dr. Loprinzi points out, this study is purely associational, so cannot show whether exercise actually causes changes in telomere length, only that people who exercise have longer telomeres."

Hormesis [1] is defined as a favorable biological response to low exposures to stressors and it is a fundamental concept in biology that applies at any given "resolution", so we have hormesis at the cell level up to hormesis at the whole body level.

In this tense, exercise is just an stressor and the key here is the amount of exercise: Too little and the hormetic response is not triggered; too much, and your body is not able to cope with it.

Given this, it is quite difficult to say if exercise, without any qualifier, is good or bad.

[1] https://en.wikipedia.org/wiki/Hormesis

METFORMIN does as per http://qz.com/431663/scientists-want-to-treat-aging-like-a-d...

Yeah, but the side-effects can be unpleasant (explosive diarrhea)

> However, as Dr. Loprinzi points out, this study is purely associational, so cannot show whether exercise actually causes changes in telomere length, only that people who exercise have longer telomeres.

https://en.wikipedia.org/wiki/Betteridge's_law_of_headlines

I don't think that that principle applies here. Betteridge's Law implies that the OP knows the answer to be "No". In this situation, the OP doesn't know the answer -- and so appropriately mentions that the headline is a question that researchers are actually asking and hoping to answer at some point.

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