Thursday, May 27, 2010

Exercise and Fitness Buffer the Life-Shortening Effects of Psychological Stress

A new article published in the on-line Public Library of Science journal reports on a study which compared the effects of chronic psychological stress on either sedentary or physically active people.

The study involved looking at telomere length in 63 healthy post-menopausal women. The researchers measured telomere length in the women, then had the women complete the Perceived Stress Scale. After this, for three days the women reported their daily investment of time (in minutes) in vigorous physical activity. The researchers then calculated the likelihood of having long or short telomeres relative to age, body mass index, education, perceived stress, and activity level.

Among the sedentary women, each unit of increase in perceived stress (on the Perceived Stress Scale) was associated with a 15-fold greater odds of having short telomeres, a marker of biological aging. However, among those who got an average of at least 14 minutes daily of vigorous exercise, the researchers found no increase in odds of short telomeres regardless of perceived stress.

In other words, it appears that people who engage in sufficient, but not excessive, physical activity have greater resistance to the aging effects of psychological stress.

The authors propose several explanations for the beneficial effects of activity:

1. Moderate physical activity appears to increase endogenous antioxidant production, which may buffer the pro-oxidative effects of stress.
2. Physical fitness and activity appear to blunt neuroendocrine responses to stress, particularly reducing sympathetic nervous system responses and cortisol production.
3. Physical activity appears to reduce cognitive rumination (i.e. it quiets the mind), which results in less sympathetic nervous system activity and lower cortisol production under stress.

In short, this study suggests that by engaging in regular physical activity we protect ourselves from both the immediate and the aging effects of stress. We would expect this from a species that evolved by route of a lifestyle that required physical activity in the pursuit of food. Proper exercise is essential to not only physical but also mental health.


Sanjeev said...

your experience is like mine

For many many years I did one or 2 sets to failure. I also did descending sets - once I could lift a weight no more I quickly reduced the weight or arranged the leverage to get the same effect & kept going.

I had been convinced that was the most time-effective way to train, even though I always burned out after a couple of months.

The ability to stick with something non productive has cost me a lot of time ...

This regimen maximizes central nervous system fatigue (the "end plates" fail, not the muscle)

The next step in the direction you're going is called "grease the groove", which taxes the muscles to the max and the CNS the least.

GTG has you do 1 to 3 reps, but NEVER EVER to failure (stopping one to 2 reps before losing good form, don't even get close to failure), using your near-maximal weights, spread out as widely as you can

It's popular for increasing maximum numbers of (chin/pull) ups. The idea is to set up a chinning station somewhere you pass several times during the day. Every time you walk past, do some chins / pulls.

But while that's the most popular application in North America, apparently the best use is for strength: all the strongest athletes in the world - Russian, Bulgarian, Chinese use this method.

Pavel Tsatsuoline is its biggest proponent at the moment.

I did this for 2 months & added 40 pounds to my deadlift (which was not so stellar to begin with, so I won't post numbers ; ( ). I'm taking a break right now; I may do endurance work for the rest of the summer & resume the deads and chins in the fall but the strength gains feel so good I may skip the endurance work this year.

Ned Kock said...

Hi Don.

Thank you for your recent posts on exercise. I hope you will continue to blog on this topic.

Under one of those posts I mentioned a study on growth hormone response to exercise. I put a graph up, with some text around it, here:

In short, growth hormone may rise 300 percent with exercise. Acute increases also occur in cortisol, adrenaline, and noradrenaline.

Criticism is welcome, either here or there. It is easy for me to make mistakes while blogging.

PaulP said...

Exercise is obviously great for life-shortening effects, in moderation. Overtraining can be terrible for one's health. My question is this. Is it better to have a fast metabolism/high body temperature or a slower metabolism/low body temperature. Some websites claim a low body temp is the root cause of many diseases, but following a paleo diet would lead to a lower body temp/slower metabolism. I am curious what the body temp, taken first thing in the morning, is of followers of a paleo diet and if having a lower body temp (around 96.5) is actually better for overall health. Thank you.

Andreas said...

Hi Don! Besides helping your strength to increase, has the new training style improved your physique? The way you look specifically!

Don said...


I don't have data on the average body temperature of people following a paleo diet. People and animals following calorically restricted diets generally have lower body temperatures and this appears to associate with a slower rate of aging and lower risk of chronic diseases.


I have barely broken some PRs in some lifts so I haven't made enough strength gains to see much if any improvement in my physique. I expect in the next 6 months I will see some improvements.

Sanjeev said...

Body temperature:
I believe it was Roy Walford who toured India, which still has a good number following the ancient tradition of extreme ascetism, and took body temperature readings of folks following that lifestyle - he found reduced body temperatures.

That was one of the bases for Walford's life extension recommendations (calorie restriction).

I don't believe he measured thyroid.

This is also an extreme non-paleo diet. Tons of milk, rice (idlis in the south), wheat (roti), corn and so on.