Can exercise change how your brain works? A new study suggests that how, and how often, older adults exercise could impact breakdown of glucose in the brain. Decreases in brain metabolism (hypometabolism) have been shown to be a characteristic of Alzheimer’s disease and predictive of cognitive decline and the conversion to Alzheimer’s in older adults. Physical activity has been shown to modulate brain glucose metabolism, but it is unclear what level of intensity and duration may be beneficial.

A recent NIA-supported study from the University of Wisconsin led by Dr. Ozioma Okonkwo found that even moderate physical activity may increase metabolism in brain regions important for learning and memory. The study asked cognitively normal, late-middle age (average age 64 years old) participants to wear an accelerometer for 7 consecutive days to measure daily physical activity. Scientists were then able to determine the amount of time each individual engaged in light (e.g., a slow walk), moderate (e.g., a fast walk), and vigorous activities (e.g., run). The physical activity data were analyzed to determine how they corresponded with glucose metabolism within brain areas that have been demonstrated to be impacted in people with Alzheimer’s.

Increasing levels of engagement in moderate physical activity were associated with increases in cerebral glucose metabolism across all brain regions examined. Vigorous activity showed an increase in metabolism only in the hippocampus (an area important for learning and memory). Light physical activity was not associated with changes in metabolism in any of the brain regions examined. Further, how long one engaged in moderate physical activity impacted the amount of brain glucose metabolism. The more time spent performing moderate level of physical activity (average 43.3 min/day to average 68.1 min/day), the greater the increase in brain glucose metabolism.

Overall, this study adds to encouraging evidence that physical activity may be beneficial for neurometabolic function. Specifically, it makes a critical contribution to the efforts to identify the intensity and duration of physical activity that confer the most advantage for combating Alzheimer’s-related changes in mid-life.