Typically, after age 30, the brain’s gray matter (the thin layers of cell bodies such as neurons and support cells involved in learning and memory) and white matter (the myelin sheath containing the nerve fibers that transmit signals throughout the brain) shrink in a manner analogous to a person’s cognitive decline. However, a study published in the February 2003 issue of the Journals of Gerontology Series A: Biological Sciences and Medical Sciences was the first to show that physical fitness may deter an older person’s loss of these vital brain tissues.
The researchers used high-resolution magnetic resonance imaging to show the loss of gray and white matter in well-educated men and women ages 55 to 79 who ranged from the sedentary to the very fit and athletic. “We found differences [among the different fitness levels] in three areas of the brain: the frontal, temporal and parietal cortexes,” said study leader Arthur F. Kramer, professor of psychology and member of the Beckman Institute for Advanced Science and Technology at Illinois.
Kramer added, “Interestingly, we found that fitness per se didn’t have any influence on brain density. It is fitness as it interacts with age that has the positive effects. Older adults show a real decline in brain density in white and gray areas, but fitness actually slows that decline.”
Kramer admitted that more research is needed to verify the benefits of fitness training for brain health. Nonetheless, his comprehensive review (published in the March 2003 issue of Psychological Science) of 18 intervention studies done between 1966 and 2001 with hundreds of subjects age 55 and older yielded similarly encouraging conclusions:
- A program involving both cardiovascular exercise and strength training seems to enhance cognitive abilities better than does either alone.
- The brains of older adults benefit more from exercise than those of younger adults, possibly because they have more to gain.
- As many current exercise guidelines occur with more than 30 minutes of exercise per session.