There is plenty of evidence from epidemiological studies of human populations for correlations between physical fitness and a slower age-related decline in brain structure and function. The research community turns out new studies of this nature on a regular basis, and the work here is a representative example of the type. While studies in humans usually cannot say anything about causation, animal studies of exercise and fitness very clearly show that exercise improves cognitive function over the course of aging, slowing the declines of age.
A new study provides new evidence of an association between cardiorespiratory fitness and brain health, particularly in gray matter and total brain volume - regions of the brain involved with cognitive decline and aging. Brain tissue is made up of gray matter, or cell bodies, and filaments, called white matter, that extend from the cells. The volume of gray matter appears to correlate with various skills and cognitive abilities.
The researchers found that increases in peak oxygen uptake were strongly associated with increased gray matter volume. The study involved 2,013 adults from two independent cohorts. Participants were examined in phases from 1997 through 2012. Cardiorespiratory fitness was measured using peak oxygen uptake and other standards while participants used an exercise bike. MRI brain data also was analyzed.
The results suggest cardiorespiratory exercise may contribute to improved brain health and decelerate a decline in gray matter. The most striking feature of the study is the measured effect of exercise on brain structures involved in cognition, rather than motor function. "This provides indirect evidence that aerobic exercise can have a positive impact on cognitive function in addition to physical conditioning. Another important feature of the study is that these results may apply to older adults, as well. There is good evidence for the value of exercise in midlife, but it is encouraging that there can be positive effects on the brain in later life as well."