Here is another example of recent data on the relationship between levels of physical activity in later life and the health of the brain. With the advent of low-cost accelerometers and more accurate data on activity, it is becoming clear that even the very modest exercise involved in activities such as cleaning or walking shows correlations with health. To to the degree that this relationship involves causation, the important mechanisms likely relate to the status of the vascular system, the rate at which tiny blood vessels suffer structural failure and destroy small portions of brain tissue. That is driven by the pace of arterial stiffening, progression of hypertension, and other factors that are slowed by regular exercise and sped up by the consequences of a sedentary life style, such as higher levels of chronic inflammation caused by visceral fat tissue.
A new study shows that a variety of physical activities from walking to gardening and dancing can improve brain volume and cut the risk of Alzheimer's disease by 50%. The researchers studied a long-term cohort of patients in the 30-year Cardiovascular Health Study, 876 in all, across four research sites in the United States. These participants had longitudinal memory follow up, which also included standard questionnaires about their physical activity habits. The research participants, age 78 on average, also had MRI scans of the brain analyzed by advanced computer algorithms to measure the volumes of brain structures including those implicated in memory and Alzheimer's such as the hippocampus. The physical activities performed by the participants were correlated to the brain volumes and spanned a wide variety of interests from gardening and dancing to riding an exercise cycle at the gym. Weekly caloric output from these activities was summarized.
The results of the analysis showed that increasing physical activity was correlated with larger brain volumes in the frontal, temporal, and parietal lobes including the hippocampus. Individuals experiencing this brain benefit from increasing their physical activity experienced a 50% reduction in their risk of Alzheimer's dementia. Of the roughly 25% in the sample who had mild cognitive impairment associated with Alzheimer's, increasing physical activity also benefitted their brain volumes.