Heart rate biofeedback attenuates effects of mental fatigue on exercise performance

Objective Cognitive control exertion increases mental fatigue and impairs subsequent physical performance. Few studies have investigated intervention strategies to attenuate the effects of mental fatigue on exercise behavior. This study examined heart rate (HR) biofeedback as a moderator of the effects of mental fatigue on vigorous-intensity exercise performance. Design Within-subjects, crossover design. Methods Participants (N = 36) completed four 20-min sessions of self-paced, cycling exercise. Exercise was preceded by 10-min high or low cognitive control manipulations crossed with HR biofeedback or no feedback during exercise in a 2 (high vs. low cognitive control) X 2 (biofeedback vs. no feedback) factorial arrangement. Participants rated their intended rating of perceived exertion (RPE) and goal commitment prior to and following the cognitive control manipulations. HR and total work were recorded during each exercise session. Results Mental fatigue was significantly greater following high cognitive control exertion, which corresponded with significant reductions in intended RPE and goal commitment. Participants exercised at a lower average HR and performed less work in the high cognitive control/no feedback condition, however, with HR biofeedback following high cognitive control exertion participants attained similar HRs and total work performed to the low cognitive control conditions, which did not differ. Conclusions HR biofeedback improves self-regulation of exercise behavior in a mentally fatigued state. Without biofeedback, fatigued people may down-regulate exercise intensity. Findings have implications for the use of HR-monitoring devices to improve intensity-based exercise prescription adherence when confronted with barriers such as mental fatigue.