Morning compared to afternoon school-based exercise on cognitive function in adolescents

Area of Science:

• Exercise Physiology
• Cognitive Neuroscience
• Adolescent Health

Background:

• Adolescents exhibit later sleep-wake cycles, potentially impacting morning alertness and learning readiness.
• High-intensity interval exercise (HIIE) is known to acutely enhance cognitive functions in adolescents.

Purpose of the Study:

• To investigate if the cognitive benefits of HIIE differ when performed in the morning versus the afternoon in adolescents.
• To compare the effects of morning HIIE, afternoon HIIE, and a no-exercise control on cognitive performance throughout the day.

Main Methods:

• A within-subjects design involving 37 adolescents (13.7 ± 0.4 years) completing three conditions: morning HIIE, afternoon HIIE, and a control (no exercise).
• HIIE protocol consisted of 10 sprints of 10 seconds each, separated by 50-second walking intervals.
• Cognitive function, specifically reaction time and accuracy, was assessed using computerized tasks at four time points daily.

Main Results:

• Morning HIIE significantly improved reaction time 45 minutes post-exercise, with benefits persisting for a later time point.
• Afternoon HIIE did not yield significant improvements in reaction time compared to the control condition.
• Morning HIIE resulted in quicker reaction times compared to both the control and afternoon HIIE conditions.

Conclusions:

• High-intensity interval exercise may be more effective for enhancing adolescent cognitive function when performed in the morning.
• Morning exercise could be a viable strategy to improve cognitive readiness in adolescents.