This preliminary study looked at whether one session of aerobic exercise changed attention in adults with ADHD. Researchers analyzed 40 adults (20 with ADHD and 20 matched healthy controls; the ADHD group's mean age was about 30 years). Each person did a computer attention test (the flanker task) on two separate days: once after 30 minutes of moderate cycling and once after watching a movie.
After exercise, the adults with ADHD responded faster on the test, both on easier matching trials and on harder conflicting trials. The healthy controls did not respond faster, and their reaction times were about the same in both conditions. On one measure of how much distraction slowed people down (the interference score), the pattern flipped: the controls, not the patients, showed a small drop after exercise. The patients' response times also became less variable after exercise.
Brain scans during the flanker task showed no exercise-related changes in either group across the whole sample. Changes in brain activity appeared only in exploratory analyses of a separate visual task and in a higher-fitness subgroup. The authors call the sample mixed in age and symptom severity, say a larger group would have been better, and note that all fitness-related analyses were exploratory.
The numbers Stats and what the terms mean
The statistics behind the plain-language claims above.
- Mehren, 2019: adults with ADHD responding faster after exercise, easier matching trials d = 0.81 and harder conflicting trials d = 0.65; the controls' drop in interference score d = 0.61; less variable response times in the adults with ADHD d = 0.78.
What the terms mean:
- d is an effect size. Roughly, 0.2 is small, 0.5 is moderate and 0.8 is large. A minus sign shows the direction of the change, not its size.
Source: Aylin Mehren, Jale Özyurt, Alexandra P. Lam, et al.. Acute Effects of Aerobic Exercise on Executive Function and Attention in Adult Patients With ADHD. Frontiers in Psychiatry (2019). doi:10.3389/fpsyt.2019.00132