A study in Taiwan found that 30 minutes of aerobic exercise induced cognition-enhancing effects in individuals with ADHD. These exercises enhanced short intracortical inhibition in individuals with ADHD while reducing it in healthy participants. The paper was published in Psychiatry Research.
Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental condition characterized by persistent patterns of inattention, hyperactivity, and impulsivity that interfere with daily functioning. People with ADHD often struggle to focus on tasks, follow through on instructions, or organize their activities. Hyperactivity manifests as excessive movement or an inability to remain still, while impulsivity may lead to hasty decisions or interruptions during conversations.
ADHD is typically diagnosed in childhood, most often at the start of school. Children with ADHD often come into conflict with school rules due to their symptoms. These symptoms can persist into adulthood and are often accompanied by cognitive impairments. ADHD is the most prevalent neurodevelopmental disorder.
Study author Hsiao-I Kuo and his colleagues aimed to explore the physiological effects of acute aerobic exercise on cognitive performance, including inhibitory control and motor learning, in individuals with ADHD. They hypothesized that these exercises would enhance pathologically reduced short intracortical inhibition in individuals with ADHD while reducing it in healthy individuals. They also expected that aerobic exercise would enhance intracortical facilitation in healthy participants.
Intracortical facilitation refers to the enhancement of cortical excitability within the motor cortex region of the brain, mediated by excitatory interneurons that increase the responsiveness of neurons to incoming stimuli. Short intracortical inhibition, on the other hand, is a process that temporarily suppresses motor cortex activity through inhibitory interneurons, helping to regulate and fine-tune motor output. Aerobic exercises are physical activities that increase heart rate and breathing over a sustained period, such as walking, running, cycling, swimming, or dancing.
The study included 26 adults with ADHD and 26 healthy individuals. In each group, 16 participants were male and 10 were female, with an average age of 23–24 years. Participants with ADHD were recruited through the outpatient clinic of the Department of Psychiatry at the National Taiwan University Hospital, while healthy participants were recruited via online announcements.
There were two study conditions: experimental and control. In the experimental condition, participants completed 30 minutes of aerobic exercise on a stationary exercise bike. They began with a 5-minute warm-up, followed by 20 minutes of exercise at the target heart rate, and ended with a 5-minute cooldown. In the control condition, participants sat on the exercise bike for 30 minutes while watching nature videos.
Each session was repeated twice. In one set of sessions, the researchers had participants complete a set of cognitive tasks before and after the intervention. These cognitive tasks evaluated inhibitory control (using the stop signal task) and motor learning (using the serial reaction time task). The second set of tasks assessed intracortical facilitation and short intracortical inhibition of the motor cortex. To measure this, the researchers used transcranial magnetic stimulation to evoke motor-evoked potentials in specific muscles, with electromyography used to record the resulting muscle activations.
The results showed that individuals with ADHD exhibited enhanced short intracortical inhibition after aerobic exercise, while healthy individuals experienced a decrease in short intracortical inhibition. Additionally, the ADHD group showed improved inhibitory control and motor learning after exercising. Changes in short intracortical inhibition were associated with improvements in motor learning in participants with ADHD.
“Aerobic exercise had partially antagonistic effects in healthy controls, and ADHD patients. Furthermore, aerobic exercise-induced cognition-enhancing effects in ADHD depend on specific alterations of brain physiology, which differ from healthy humans,” the study authors concluded.
The study contributes to the scientific understanding of the neural effects of aerobic exercise on adults with ADHD. However, the study was conducted on a relatively small group of young adults. Studies with larger samples and other demographic groups may yield different results.
The paper, “Acute aerobic exercise modulates cognition and cortical excitability in adults with attention-deficit hyperactivity disorder (ADHD) and healthy controls,” was authored by Hsiao-I Kuo, Michael A. Nitsche, Yen-Tzu Wu, Jung-Chi Chang, and Li-Kuang Yang.
