Impact of aerobic exercise trials with varied intensity patterns on perceptions of effort: an evaluation of predicted, in-task, and session exertion

Perceptions of effort provide a sense of momentary exertion during exercise, but may have value when considered prior to and after exercise. The purpose of the present study was to determine the relationship between perceived exertion assessed before, during, and after trials of aerobic exercise fixed for total work but varied on intensity patterns. Twenty participants completed five trials of treadmill exercise that included planned intensity variations every 10 minutes to result in the same total work. Perceived exertion was taken before, during, and after exercise. Analyses confirmed each trial was similar in terms of average speed and heart rate (P > 0.05). Predicted and session exertion results indicated that the steady exercise bout was perceived as easier than many trials of varied speed (P < 0.05). Trials including an intense segment in the middle or end of the session were perceived as more difficult than sessions that varied intensity otherwise or remained constant. Similarly, trials that remained constant during the 30-minute period were perceived as less aversive than most other trials. These findings suggest that exercise sessions involving a steady intensity throughout are viewed as less taxing than sessions with variable intensity, especially when compared to sessions that conclude with a higher intensity finish.