Brain and Brawn
I can’t remember the last time I spoke to someone who was excited at the prospect of getting older. People fear different things, but it’s safe to say most concerns surround declining physical and/or mental well-being. For years, the medical community has promoted cardiovascular exercise as the best for the prevention and intervention of disability and disease. Aerobic exercise was said to keep the heart and lungs strong as well as aid in neurogenesis, or the creation of new neuronal cells in the brain, especially in those portions of the brain associated with memory and thinking. While this recommendation still holds true, recent studies are showing that resistance training is as effective, if not more, at stimulating neurogenesis in the same areas of the brain.
Recently, a few studies examining the effects of exercise on the stimulation of Brain-derived neurotrophic factor (BDNF) were presented at the annual meeting of the Society of Neuroscience in November. BDNF is part of a family of proteins responsible for the growth, survival and differentiation of nerve cells, and maybe the underlining factor responsible for exercise induced effects on cognition and mental well-being. In one study, researchers from Brazil secured weights to the tails of a group of rats and had them climb ladders for five sessions a week. This study, which measured the levels of BDNF, found that the weight lifting rats compared favorably to the rats that ran on a wheel. The sedentary rats showed very low levels of BDNF. The other study presented studied rats that ran on a weighted wheel (resistance being equivalent to 30% of the rats body weight) compared to rats that ran on an un-weighted wheel. Not only did the rats moving the loaded wheel pack on muscle mass but they also showed significantly greater gene activity and levels of BDNF within their brains. Although these results are not definitive proof, it is, at very least, an indication that further study is warranted.
One such study is underway at the University of British Columbia where principal investigator, Teresa Liu-Ambrose, has found that older women who lifted weights performed significantly better on various tests of cognitive functioning than women who completed toning classes. Ms. Liu-Ambrose has hypothesized that the beneficial effect of strength training on cardiovascular health accounts for some of the improvement in function, but also stated “resistance training at first requires an upsurge in brain usage.” She goes on to mention the involvement and stimulation of the brain during exercise using proper form and technique could contribute to greater cognitive functioning. In addition to increased cognitive demand, the brain is responsible for activating the appropriate muscles, the necessary type and quantity of muscle fibers (efficiency) and activating the various energy systems that need to be involved.
One word to the wise, conventional wisdom often suggests that if some thing is good, more is better. When it comes to exercise, this is not always the case. Another study recently published showed that excessive exercise in postmenopausal women was linked to lower cognitive function. Although this study was assessed by questionnaire, not known for their reliability, we do know that overtraining stimulates the release of cortisol. Cortisol in excess has been linked to depression and lower levels of neurogenesis.
Sharon Begley’s January 3, 2011 Newsweek article “Can You Build a Better Brain?” presented a review of what neuroscience has learned, and has yet to learn, about improving cognitive function. Supporting additional research regarding strength training and the brain is a statement by Columbia University’s Yaakov Stern that “the research so far suggests that cognitive training benefits only the task used in training and does not generalize to other tasks.” Stern’s input begs the question, if training cognition doesn’t help, what does? In answer to that, Begley quotes Art Kramer of the University of Illinois at Urbana-Champaign who studied the effect of aerobic exercise. Kramer found that “A year of exercise can give a 70-year-old the connectivity of a 30-year-old, improving memory, planning, dealing with ambiguity, and multitasking… fitness training [stimulates] the molecular and cellular building blocks that underlie many cognitive skills. It thus provides more generalizable benefits than specifically training memory or decision-making.”
In relation to anti-aging, the adage of ‘use it or lose it’ is a good guide for the maintenance of movement and cognitive function, and it appears these are no longer unrelated. These studies suggest that you can engage both the brain and the body by learning and practicing new or complex movements under a safely prescribed load. My recommendation would be to start with body weight exercises and focus on learning how to move properly and then progress to greater loads. The other implication of this study is that checking out during your exercise routine and simply going through the motions to just ‘get it done’ may not be as beneficial. Practicing movements with the intent of getting better not only improves your physical health, but also may contribute to your mental well-being