Acute aerobic exercise to recover from mental exhaustion - a randomized controlled trial.

Purpose: Prolonged periods of intense cognitive activity lead to a state of mental exhaustion. While widespread strategies to recover from mental exhaustion (i.e., watching TV) are non-effective, aerobic exercise seems to be a promising approach. This can be explained by the acute and chronic aerobic exercise-induced benefits on the central nervous system.

Methods: This study investigated the potential of a single bout of moderate aerobic exercise (65-75% of each participants' individual V˙O2peak) to recover from experimentally induced mental exhaustion. A randomized controlled trial on healthy adults (N = 99) was conducted. They performed 60 min of a cognitively demanding test battery, in order to induce mental exhaustion. Subsequently, they were randomized to one of three treatments: 30 min of moderate aerobic exercise on a cycle ergometer, 30 min of a simple lower body stretching routine (= active control treatment) or watching a popular sitcom (= passive control treatment). Cognitive flexibility performance, mood, tiredness, restlessness, self-perceived cognitive capacity, and motivation were assessed before and after treatment.

Results: The empirical results showed that moderate aerobic exercise led to a better recovery for cognitive flexibility (mean difference divided by pooled standard deviation, Cohen's d= 0.737), mood (d= 0.405), tiredness (d= 0.480), self-perceived cognitive capacity (d= 0.214), and motivation (d= 0.524) compared to active control treatment. Moderate aerobic exercise was also more effective than passive control treatment (d= 0.102 - 0.286) with the exemption of tiredness (d= 0.015) and restlessness (d = -0.473).

Conclusion: In conclusion, this study suggests that a single bout of acute aerobic exercise supports regeneration of cognitive flexibility performance and of subjective well-being. This holds true not just compared to artificial active control treatment but also compared to widespread leisure time activity, namely watching TV.