Exercise

September 9, 2009

Exercise for Your Brain?

Kudos to Scientific American, a terrific magazine that consistently publishes quality, unbiased science-based articles in language that can be understood by the general public. The issue of July, 2009 with an article called Fit Body, Fit Mind? Your Workout Makes You Smarter was particularly enlightening.

As you probably guessed from the title, the article explores the role of exercise in improving brain function and preventing the age-related loss of mental acuity. It’s a fascinating and important subject. While most people realize that exercise provides a multitude of benefits on physical capacity, the impact on the brain often goes unheralded. But without question, a healthy body does, in fact, translate into a healthy mind. This isn’t opinion: it’s backed up by a large amount of peer-reviewed research.

The article poses several theories as to the correlation between exercise and brain health. First, it’s believed that simply reducing the incidence of major diseases (such as diabetes, hypertension and various forms of cancer) is a factor in and of itself. These diseases have been shown to impair cognitive function, so it stands to reason that reducing their prevalence should necessarily confer a positive effect on cognition.

Exercise also seems to have a direct effect on the nervous system, which is of course largely controlled by the brain. Given that muscles are activated by nerves, neurologic improvements shouldn’t come as a surprise. Although most of the research in this area has been conducted on animals, exercise has been shown to increase the formation of various types of nerve cells responsible for sending and receiving communication signals, as well as expanding the density of capillaries which supply oxygen to the brain. The article documents the research on this quite nicely.

The only major issue I had with the article was the author’s focus on aerobic exercise while neglecting to mention the cognitive benefits associated with resistance training. This is a glaring omission, and one that needs to be publicized. Multiple studies have shown that lifting weights does, in fact, confer significant effects on mental health. A recent paper by Liu-Ambrose and Donaldson (2009) examined this topic in detail, providing an extensive evidence-based review of the research. Interestingly, the potential mechanisms for resistance exercise improving brain function seem to be different than those associated with aerobic exercise, potentially involving the actions of IGF-1 and homocysteine. If true, this suggests that performing both aerobic and resistance training might have a syngergistic effect on brain function, combining to optimize mental health better than either modality alone. It’s why Liu-Ambrose and Donaldson concluded their review by emphasizing the importance of undertaking “both aerobic-based exercise training and resistance training not only for “physical health” but also because of the almost certain benefits for “brain health”.” Powerful words!

Otherwise, the Scientific American article was well-written and balanced in its reporting — something other supposedly reputable publications should take note of. I’d encourage everyone to give the article a read if you haven’t done so already.

Stay Fit!

Brad

Liu-Ambrose T, Donaldson MG. Exercise and cognition in older adults: is there a role for resistance training programmes? Br J Sports Med. 2009 Jan;43(1):25-7.

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