Physical activity protects our body from cognitive stress

There are few of us who can honestly say they are not stressed out at least some of the time. Too much to do, not enough time, looming deadlines, financial concerns, health problems, etc. can all cause us to feel on edge.

Your heart rate and blood pressure soar, you start perspiring, sleeping becomes a challenge, you’re irritable, and so on.

As you might have imagined, chronic psychological stress negatively impacts on your physical health, increasing the chances of countless chronic diseases. Additionally, stress can also reduce your lifespan.

Findings on a more cellular level suggest that psychological stress expedites the aging process of your body’s cells. Specifically, stress has been correlated with telomere shortening of a cell’s chromosomes. Every time a cell divides, and it replicates and shares the genetic information wound up in its chromosomes with its new copy, the new cell retains a slightly smaller end section of the chromosome, termed the telomere. When the telomere gets to a critical length, the cell reaches a point it can no longer divide properly.

When this begins to occur on a systemic level, you are in trouble.

And this is essentially what happens with aging, leading to cellular senescence.

So what effect, if any, does exercise have on this negative impact of psychological stress on cellular aging?

A recent study investigated this very question in a sample of 63 healthy post-menopausal women who were assessed for stress via questionnaire, physical activity levels over a 3 day period, and telomere length via a process I barely understand, so I won’t try to explain (it is Friday, after all).

For purposes of comparison, the women were divided into sedentary (< 33 minutes during the 3 days) or active (>33 minutes during the 3 days) – not a very high bar for activity.

Not surprisingly, participants with higher levels of stress were less likely to exercise, have higher BMI, less years of education, and shorter telomere length.

In terms of exercise protecting you from the negative cellular effects of stress, the authors found the following:

Among sedentary individuals, a 1 unit increase in perceived stress was associated with a 15-fold increased risk of having short telomeres (in the lower tertile of telomere length in the entire sample).

Among active individuals, a 1 unit increase in perceived stress had NO RELATIONSHIP with telomere length.

In other words, those who are active (and just barely so, based on the categorization in this study: 11 mins per day) seem to be protected against the cellular damage caused by cognitive stress

Keep in mind these analyses accounted for differences in BMI, education, age, and anti-oxidant use.

Bottom line:

Just in case you needed another reason to be physically active, regular activity may protect your cells from the damage caused by daily stresses of modern life. Unfortunately, those people who could benefit the most from physical activity – stressed individuals – are least likely to be active.


Puterman, E., Lin, J., Blackburn, E., O’Donovan, A., Adler, N., & Epel, E. (2010). The Power of Exercise: Buffering the Effect of Chronic Stress on Telomere Length PLoS ONE, 5 (5) DOI: 10.1371/journal.pone.0010837

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4 Responses to Physical activity protects our body from cognitive stress

  1. Travis says:

    Just a point for clarification (aimed at the study authors rather than Peter) – the control group in this study was actually “inactive”, rather than “sedentary”… at least that’s how we’re hoping people will start to use the terms (and it seems that people are starting to get on board). In other words, the control group wasn’t getting enough physical activity (hence they are inactive), but we don’t know how much time they spent being sedentary. It seems like a relatively minor detail, but it will make research far simpler when the terms are used a bit more consistently (up until now inactive and sedentary have been used interchangeably, and depending on the paper it could mean either high levels of sedentary behaviour, or low levels of physical activity).

  2. I find myself wondering about the correlation/causation issues here. How do we know that reduced telomere length is caused by reduced physical activity, rather than the reverse, or both having some other common cause? Perhaps having shortened telomeres makes physical exercise more difficult/unpleasant for some reason or is associated with conditions that cause this, such that people who are already have short telomeres are more likely to drop their exercise programs when their lives become stressful?

  3. tbell says:

    sounds like we need to do a intervention study with random assignment…

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