A new study is shedding light on the benefits of physical exercise on our cognitive health. Published in the medical journal Neurology in January 2019, the research indicates that activities such as walking or cycling have a positive effect on executive function. How were the scientists able to pinpoint the link between aerobic exercise and our thinking skills?

Our body produces energy both aerobically and anaerobically. The two types of metabolism are distinguished by whether or not they use oxygen produced by breathing. By drawing from a reserve that mobilizes different substrates (mainly carbohydrates and lipids), aerobic metabolism releases energy relatively slowly but regularly, which allows for endurance over longer periods.

Led by Yaakov Stern, a researcher at Columbia University in New York, this study looked at the possible effect of aerobic exercise on cognitive abilities, and more specifically, executive function. Executive function involves three processes that come into play when we find ourselves in a new or non-routine situation: inhibitory control (to prevent or stop producing a response), flexible thinking (switching from one behavior to another), and planning (to organize a series of actions in sequence). Stimulating these "high-level” functions allows us to reason, make decisions, and solve problems.

The study was carried out on 132 participants, ages 20 to 67, with below average fitness levels. None of the subjects were smokers. The participants were randomly assigned to one of the two training groups at a fitness center and followed over a period of six months (four times/week). Each person wore a heart rate monitor. Members of the first group performed aerobic exercises (walking on a treadmill, using an elliptical machine, etc.) The activities were intensified during the first month. The subjects then exercised at 75% of their maximum heart rate. Meanwhile, the members of the second group performed stretching and weight training exercises designed to increase strength and flexibility.

Each participant completed targeted memory and thinking skill tests at the beginning, middle (three months) and end (six months) of the study. The subjects also underwent brain scans using an MRI. The results indicate that their aerobic capacity increased significantly. Their body mass index (BMI) dropped significantly, but not in the stretching/weight training group. In the "aerobic" group, subjects improved their overall tests scores by 0.5 points, a significant difference from the other group (who saw an increase of 0.25 points). The difference became even more pronounced with age. At age 40, the aerobic group showed 0.228 standard deviations of improvement and 0.596 at age 60. In addition, the scientists observed an increase in the thickness of the left frontal cortex, suggesting that aerobic exercise contributes to brain health, even in the youngest subjects.

This research provides new evidence of the benefits of regular physical activity, and specifically aerobic exercise, on improving executive function. Note that scientists have not found any links between physical exercise and other measures of cognitive function, including memory.