fitness and brain power

An important new US study has provided the first empirical proof that aerobic fitness protects the brain as well as the body from the degenerative effects of ageing.

The human brain gradually loses tissue from the third decade onwards, with concomitant declines in cognitive (intellectual) performance. And given the projected rapid growth in aged populations and the staggering costs associated with geriatric care, identifying mechanisms that may reduce or reverse brain deterioration is rapidly emerging as an important public health goal.

Previous research has demonstrated that aerobic fitness training improves cognitive function in older adults and can enhance brain health in ageing laboratory animals. But no previous study has demonstrated a direct protective effect of fitness on ageing brain tissue.

The participants in the current study were 55 right-handed, high-functioning, community-dwelling over-50s, recruited locally by researchers based at the University of Illinois. All had their brains scanned by high-resolution magnetic resonance imaging (MRI), with the resultant images scanned for systematic variation in tissue density as a function of age, aerobic fitness (as assessed by a one-mile walk protocol) and other health markers.

Consistent with previous studies, the researchers observed substantial age-related deterioration in tissue densities in the frontal, parietal and temporal cortices of the brain. More importantly, though, they found that losses in these areas were substantially reduced as a function of cardiovascular fitness, quite independently of other ‘moderator variables’, including alcohol and caffeine consumption, HRT, education and hypertension.

The researchers state that: ‘the role of cardiovascular fitness as protector and enhancer of cognitive function and [central nervous system] integrity in older adults appears to have a solid biological basis’. The results also ‘suggest a rather simple and inexpensive mechanism to ward off the effects of senescence on human brain tissue’.

Most importantly, the regions and tissue that show the greatest sparing with aerobic fitness are the ones that play central roles in successful everyday functioning, while declines are associated with a variety of clinical syndromes, including schizophrenia and Alzheimer’s disease.

‘Future research examining the benefits of aerobic fitness on the functional and structural integrity of the CNS in clinical populations seems both promising and highly desirable,’ the researchers conclude.

J Gerontol A Biol Sci Med Sci 2003 Feb; 58(2):176-180