Exercise Produces Short Term Cognitive Benefits in Middle Age
The brain has evolved to operate at the edge of its capacity; the normal operation of neural tissue requires a lot of energy, derived from nutrients and oxygen provided in the blood stream. That the increased blood flow that occurs following exercise improves cognitive function in the short term is indicative that there is room for improvement in the physiological support provided by the body for the normal operation of the brain. This remains true in later life, as the data here shows.
The research team leveraged smartphone technology to interact with participants multiple times during their regular daily lives. Over the course of nine days, participants checked in six times a day, approximately every 3.5 hours. During each check-in, participants reported if they had been physically active since their last check-in. If they were active, they were asked to rate the intensity of their activity - light, moderate or vigorous. For example, walking and cleaning were considered light intensity while running, fast biking, and effortful hiking were considered vigorous intensity. Participants were then prompted to play two "brain games," one designed to assess cognitive processing speed and the other designed to assess working memory, which can be a proxy for executive function.
The team analyzed data from 204 participants who were recruited for the Multicultural Healthy Diet Study to Reduce Cognitive Decline & Alzheimer's Risk. Data was collected during the study's baseline period. Participants were between the ages of 40 and 65 and residents of the Bronx, NY who had no history of cognitive impairment. The team found that when participants reported being physically active sometime in the previous 3.5 hours, they showed improvements in processing speed equivalent to being four years younger. While there were no observed improvements in working memory, the response time during the working memory task mirrored the improvements observed for processing speed.
Additionally, people who reported being active more often experienced greater short-term benefits compared to those who reported less physical activity overall. This suggests that cognitive health benefits may increase with regular physical activity. However, more research is needed to understand how much physical activity and the frequency and timing of being active influences cognitive health.