The positive effects of exercise on mental health have been well established — exercise promotes both cognitive function (especially as we age) and psychological health. 

In keeping with our models of understanding, though, much of the research on those effects has focused on aerobic exercise, so it’s interesting to shed some light on strength training to see how it stacks up.

Cognitive decline is prevalent among older individuals. In fact, nearly 50 per cent of people over the age of 70 will show Alzheimer’s disease pathology. 

The good news, though, is that “genetics and exercise habits contribute roughly equally to the risk of eventually developing dementia.” Whatever your genetics, you have complete choice over one-half of that equation. In implementing that choice effectively, it helps to recognize the strong correlation between ‘muscle’ and ‘mental’. For instance, a study descriptively titled “Handgrip Strength as a Means of Monitoring Progression of Cognitive Decline” demonstrated that people with a stronger grip — an indicator of overall strength — “score higher on tests of memory and reaction time, as well as on assessments of verbal and spatial abilities. This means grip strength can be used as a marker of cognitive decline.”

That’s about as counterintuitive as saying push-ups can be used as a marker of future cardiovascular risk. Fortunately, it works both ways — people who improve their muscle strength also show significant improvements in cognition. 

The “Study of Mental and Resistance Training” involved 100 adults with mild cognitive impairment — a condition that increases the risk of dementia. The participants did strength training two to three days per week for six months and had an 18-month follow-up. Not only did the training significantly improve overall cognitive function, testing showed that those improvements had been maintained even 18 months after the training ended.

Strength training offers psychological benefits as well. As a major review of the mental health benefits of strength training in adults found, those benefits included a “reduction of symptoms in people with fatigue, anxiety, and depression; pain alleviation in people with osteoarthritis, fibromyalgia, and low back issues; improvements in cognitive abilities in older adults; and improvements in self-esteem.”

Depression is highly prevalent; it affects more than 300 million people worldwide and is Europe’s most costly mental health disorder. It’s of particular interest, then, to consider a meta-analysis that set out to determine the antidepressant effects of strength training.

It looked at 33 randomized clinical trials involving 1,877 participants and concluded that “resistance exercise training significantly reduced depressive symptoms among adults regardless of health states, total prescribed volume of resistance exercise training (RET), or significant improvements in strength.”

Another study worked with elderly individuals who had been clinically diagnosed with depression. Remarkably, it found that after a 10-week program of three sessions of resistance training a week, almost 80 per cent of the participants were no longer clinically depressed. That’s an astounding result, and suggests that the sarcopenia epidemic might underlie the widespread incidence of depression as well. Another noteworthy benefit of strength training is that its interventions “are free from the adverse effects and high costs associated with antidepressant medications and psychotherapy.”

Reprinted with courtesy from Deep Fitness (North Atlantic Books, 2021) by Philip Sheperd and Andrei Yakovenko

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