Strength Training and the Brain

Lots of evidence points to the usefulness of aerobic exercise for maintaining and improving mental functioning (see a previous blog post here and an extensive review article here). It is not as clear, though, whether strength training has an effect. An article in JAMA Internal Medicine shows that even a modest amount of resistance training (60 minutes two times a week for 6 months) can improve cognitive function in older women with evidence of mild cognitive impairment (MCI). MCI is defined as a condition in which persons have clear evidence of below average cognitive function in an area such as memory and in addition report that they have memory difficulties. It’s considered an important condition in part because people with MCI are believed to be an increased risk of developing Alzheimer’s disease.

While other studies have shown that resistance training can help cognitive functioning, this study compared strength training with aerobic exercise (walking) and a less intense “balance and tone” intervention. The authors also studied the impact of their interventions on the brain using functional MRI (fMRI). Results showed that strength training was associated with improvements in cognitive function on several study measures, including an executive function measure (the Stroop task) and a memory task. In a subgroup of people who completed fMRI, the strength training was associated with changes in brain function during mental activity. The authors conclude that strength training can help to improve cognitive function in women with MCI, and may be a useful strategy in helping maintain cognitive function in persons at risk for decline.

Reference:

Nagamatsu, LS et al. (2012). Resistance training promotes cognitive and functional brain plasticity in seniors with probable mild cognitive impairment. JAMA Internal Medicine, 172, 666-668. Full article available without charge here.

Physical Activity and How Long You Live

Lots of research has shown that, at least over short periods of time, people who are physically active are more alert, remember things better, and are in better health. But does that mean that they live longer?  A recent review article looked at this question.

The authors found 13 papers that looked at the difference in life between physically active and inactive people. The paper is a little short on details about how “physically active” was defined. The paper review, for example, might have looked at elite athletes, but it’s not clear whether they maintained physical activity throughout life. Even with this problem, people described as physically active lived on average several years longer than those who weren’t.

One interesting finding was that leisure-time physical activity may be more important than having a job that demands physical activity — those who reported more leisure time physical activity also had slightly longer lives. The authors only found one paper that looked at strength training (those people had slightly longer lives) and none looked at possible confounding variables. For example, maybe people who are in general healthier are more likely to be physically active and live longer as well.

Reference:

Reimers CD, Knapp G, Reimers AK (2012). Does physical activity increase life expectancy? A review of the literature. Journal of Aging Research, article ID 243958. Open source. Available here.