Aerobic exercise modulates orbitofrontal-amygdala connectivity, reduces negative emotions in adolescents

A study by researchers from several centres in Beijing and the School of Public Health at the University of Hong Kong (HKU) indicates that moderate-intensity aerobic exercise reduces fatigue and depression in adolescents via modulating orbitofrontal-amygdala functional connectivity.

The researchers recruited 24 healthy males aged 18–19 years, who were randomly assigned to complete 30 minutes of aerobic exercise on a cycle ergometer or a reading task. All participants completed pre- and post-test behavioural questionnaires, heart rate monitoring, and MRI scans. [Life (Basel) 2021;11:577]

Generalized estimating equation analysis used to characterize the change in behavioral scores between the two groups over time revealed significantly greater reduction in fatigue and depression scores (p<0.001 for both) in the aerobic exercise group, while no significant changes were observed in the control group. 

“After a single bout of acute aerobic exercise, participants reported a significant reduction in negative emotions, which is consistent with earlier literature,” noted the researchers. [Cogn Emot 2017;31:834-843] “One possible psychological mechanism that might contribute to this is distraction caused by acute exercise. Moreover, exercise could alter emotional response style and reduce negative repetitive thinking. In addition, accomplishing a task that requires effort, such as physical exercise, creates a feeling of control that reduces negative emotions.” [Health Psychol 2017;36:560-567; J Appl Sport Psychol 1998;10:268-280]

After the intervention, the aerobic exercise group showed significantly increased functional connectivity between the right amygdala and the right orbitofrontal cortex (OFC), with no significant change in functional connectivity between the left amygdala and the whole brain. The researchers also calculated the correlation between MRI connectivity and emotional scores. The results demonstrated that the altered right OFC–amygdala functional connectivity was significantly correlated with changes in depression score in the aerobic exercise group (p=0.014, controlling for age, baseline heart rate and exercise heart rate), while no correlation was observed in the control group.

“It is well established that the OFC plays a crucial role in uninstructed negative emotion modulation and is responsible for conscious regulation of negative affect. In addition, aerobic exercise has been shown to promote cognitive reappraisal and emotional regulation by activating the orbitofrontal cortex in young women. Therefore, it is likely that the improvement of emotional experience induced by physical activity is related to the enhanced cognitive process caused by increased right OFC–amygdala functional connectivity,” explained the researchers. [Soc Cogn Affect Neurosci 2015; 10:10-18; Soc Cogn Affect Neurosci 2007;2:303-312; Behav Brain Res 2021;406:113233]

“The neurologic evidence from the current study supports the beneficial effects of moderate aerobic exercise on regulation of negative emotions. The neural modulation and resulting optimized functional connectivity between the amygdala and other cortical regions induced by exercise offers a promising direction for prevention and clinical treatment of emotional disorders, such as depression, in late adolescence,” concluded the researchers.