Exercise fetishism, genetic confounds

I observed a few days ago that, at age 66, my physical capabilities were in visible decline.

"Let it be noted that in my mid sixty-sixth year I finally realised that my body was not immortal and that age would wreak its toll on both competences and recovery time.

"I observed recently that due to over-enthusiastic lifting, I was now experiencing chronic elbow joint and tendon twinges which have not yet recovered. As a consequence I have to rethink this whole weight-lifting thing.

"I suspect I will be doing more running and cardio work going forwards, with strength stuff more focussed on the core and upper back, where I have historically had muscle issues. Biceps and triceps can maybe go hang!"

So at some point I'll be packing away those weights, and going for a brisk walk rather than a run.

But will it make any difference?

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We're led to believe that vigorous exercise is the only way to stave off the myriad complaints of old age: heart disease, cancer, dementia .. .  But such exciting and well-publicised studies are correlative and seldom investigate genetic confounds. The only way to be sure is to conduct twin studies.

And so I was led to this news item: "Exercise Differences Do Not Produce Longevity Differences in Identical Twins". You should read it, but I will just quote the bottom line.

"High physical activity level was associated with longer lifespan when looking at non-identical twins that differ for their genetic background.

"However, in identical twins, that share the same genetic background, in pairwise analyses comparing physically active members of a twin pair with their inactive co-twin, there was no difference in lifespan.

"Our results are consistent with previous findings, that animals that have high aerobic capacity are physically more active compared to animals with low aerobic capacity. The findings in human twins were in agreement with this: discordance in physical activity level was clearly more common among non-identical twins than in identical twins showing an effect of genetic background on physical activity level.

"Vigorous physical activity in adulthood did not increase lifespan in human twins, even though physical activity is well-known to have various positive effects on health, physical fitness, and physical function.

"Based on our findings, we propose that genetic factors might partly explain the frequently observed associations between high physical activity level and later reduced mortality in humans. "

I therefore conclude that backing off from intensive physical exercise is unlikely to have much impact on either my general state of health or my longevity, assuming I avoid perverse outcomes such as complete indolence or gross obesity.

We sometimes counterpose exercise to everything else we do, as if our bodies would turn into jellyfish if we failed to lift those weights, or run those miles.

But formal exercise simply adds the icing on the cake to any reasonably active lifestyle.

It's not as if the opposite to vigorous exercise is going to be chronic bed rest.