A New Reason to Build Muscle: Brain Health

Now that Canada’s very short beach season is coming to a close once again, you may be tempted to shove dumbbells to the back of the closet — to let go of your vanity, forget about bulging muscles and instead focus on a whole-body aerobic fitness that’s so tightly linked to health and longevity.

But a recent study by researchers at McGill University, Published in the journal JAMA Network Open, offers a new reason to keep working on building muscle: It’s good for your brain, not just your muscles. The findings suggest that greater muscle mass helps stave off cognitive decline in older adults beyond what you would expect based on their exercise levels alone.

The results are from more than 8,000 older adults in the Canadian Longitudinal Study of Aging, with an average age of 73. They underwent a series of baseline assessments that included X-ray measurement of their muscle mass, a combination of 10 cognitive tests and questionnaires about exercise habits and other health characteristics. Cognitive tests were returned three years later.

Basically, nearly one-fifth of the subjects met pre-set criteria for low muscle mass. Over the next three years, compared to those with normal muscle mass, these people had significantly reduced reaction times and executive function, the cognitive skills that enable you to plan, focus attention, and prioritize your actions.

On the surface, these results are not surprising. After all, Stephanie Chevalier, a professor at the McGill School of Human Nutrition and senior author of the study, points out, previous studies have found that lower strength and less physical activity predict more rapid cognitive decline. But there is a difference between using muscle and simply owning it.

“The question we asked in our study is: When we consider strength and physical activity, does muscle mass have an independent predictive role in cognitive decline?” Dr. Chevalier explains.

Using statistical techniques, the researchers were able to compare subjects with equivalent muscle strength, as assessed by a hand grip test, and equivalent exercise habits. Sure enough, those with lower muscle mass still had a subsequent decline in executive function, suggesting that the muscle tissue itself has some sort of neuroprotective function.

Knowing exactly how muscles help the brain remains a challenge. There are a lot of indirect links: Those with more muscle are generally more active, which may help keep oxygen-rich blood flowing to the brain, for example.

But Dr. Chevalier’s findings suggest there may be more direct mechanisms, too. One possibility is a role Mukins, a group of hormone-like molecules produced by muscle cells that can travel to the brain and affect mood, learning and other cognitive functions. Greater muscle mass may also help keep blood glucose levels in check, protecting the brain from damage.

This does not mean that strength training is the only way to improve brain health. 2014 study which followed 150,000 walkers and runners over 17 years, found that meeting the standard recommendation of 150 minutes of moderate aerobic exercise per week was associated with a 25 percent reduction in the likelihood of developing Alzheimer’s disease. And those who did twice as much exercise had a 40 percent lower risk of injury.

So if you want to cover all your bases, choosing between cardio and weights is easy: do both. Incorporate some resistance training into your routine a few times a week. You don’t necessarily need to lift heavy weightsbut push hard enough so that you reach at least eight out of 10 at the end of each set.

In addition, Dr. Chevalier adds, make sure you have a well-rounded diet that contains enough protein, ideally spread throughout the day rather than concentrating on one massive protein bomb at dinner. There is evidence that the elderly are becoming Less response to muscle building stimulus to proteinSo aim for about 0.4 grams of protein per kilogram of body weight with each meal. For someone who weighs 150 pounds, that amounts to 27 grams of protein, which is the equivalent of a tuna sandwich, a cup of milk and a handful of almonds.

And remember, the goal is still not to impress everyone at the beach next year. A more realistic goal for seniors, says Dr. Chevalier, is to preserve the muscle you have and prevent further losses, citing one strict rule of exercise that no one disputes: “Use it or lose it.”

Alex Hutchinson is the author of Endurance: Mind, Body, and the Strangely Flexible Limits of Human Performance. Follow him on Twitter Tweet embed.

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