McMaster University, Department of Kinesiology, Hamilton, ON, Canada.
Ann Behav Med. 2019 Mar 28;53(5):405-414. doi: 10.1093/abm/kay052.
Exerting cognitive control results in mental fatigue, which is associated with impaired performance during physical endurance tasks. However, there has been little research on the effects of mental fatigue on people's perceptions or behaviors involving lifestyle or recreational exercise.
The purpose of this study was to examine the effect of mental fatigue on intended physical exertion and exercise performance reflective of current physical activity guidelines.
Using a counterbalanced design, participants completed two 50-min experimental manipulations (high vs. low cognitive control exertion) before exercising at a self-selected intensity for 30 min. At visit 1, participants performed a graded exercise task to gain familiarity with a range of exercise intensities and rating of perceived exertion (RPE) while exercising. At visits 2 and 3, participants rated their intended RPE for the exercise session, performed the experimental manipulations, re-rated their intended RPE, and then completed 30-min of exercise on a cycle ergometer. Total work performed while exercising was recorded for each session.
Compared with the low cognitive control condition, the high cognitive control manipulation resulted in significantly greater mental fatigue (d = .73), significantly greater reductions in intended RPE (mean difference = -0.62), and significantly less total work (-12.7 kJ) performed during the exercise session.
Mental fatigue alters the amount of physical effort people are willing to invest in an exercise workout and follow through with those intentions by doing less work. These are the first results showing people may deliberately adjust their physical effort to cope with mental fatigue.
发挥认知控制会导致精神疲劳，这与身体耐力任务中的表现受损有关。然而，很少有研究关注精神疲劳对人们的感知或涉及生活方式或娱乐性运动的行为的影响。
本研究的目的是检验精神疲劳对意图体力活动和反映当前体力活动指南的运动表现的影响。
使用平衡设计，参与者在自我选择的强度下进行 30 分钟的运动之前，完成了两次 50 分钟的实验操作（高认知控制用力与低认知控制用力）。在访问 1 中，参与者进行了分级运动任务，以熟悉一系列运动强度和感知用力评级（RPE），同时进行运动。在访问 2 和 3 中，参与者对运动期间的预期 RPE 进行了评分，进行了实验操作，重新评分了他们的预期 RPE，然后在自行车测力计上完成了 30 分钟的运动。记录每个会话中运动时完成的总工作量。
与低认知控制条件相比，高认知控制操作导致明显更大的精神疲劳（d =.73），明显降低了预期 RPE（平均差异=-0.62），并且运动期间完成的总工作量（-12.7 kJ）明显减少。
精神疲劳改变了人们愿意投入到锻炼中的体力活动量，并通过减少工作量来贯彻这些意图。这些是首次表明人们可能会故意调整体力活动以应对精神疲劳的结果。
