A recent study published in Neurology revealed that people with a lower exercise capacity in midlife were more likely to have smaller brains 20 years later, compared with people who had high fitness levels in middle age.
They also found that people whose blood pressure and heart rate went up more during exercise were more likely to have smaller brains down the line. Higher-than-average blood pressure and heart-rate spikes could indicate a lack of physical fitness.
Past research has also shown that exercise makes the brain better able to combat cognitive decline.
Read more at Time.com.