Effects of fitness level and exercise intensity on pain and mood responses

Abstract

Background: The phenomenon of exercise-induced hypoalgesia and concomitant mood changes is well-established. How exercise-induced hypoalgesia and affective responses are shaped by the intensity of an acute exercise bout and individual fitness levels is as yet not well-understood. This study investigates whether heat pain threshold (PTh), pain tolerance (PTol) and affective parameters are modulated by the intensity of an acute exercise bout and/or individuals’ fitness level. Stronger analgesic responses are hypothesized after high-intensity exercise in physically fitter subjects, possibly in sync with concomitant mood changes. Methods: Thirty-three healthy men were recruited (sedentary: N = 17 or recreational: N = 14; mean age: 25.3 ± 4.4 years). After a fitness assessment on a cycle ergometer, subjects underwent three experimental conditions on separate days: high (20 min exercise 20% above lactate threshold), low (20 min exercise 20% below lactate threshold) and control (seated rest). Before and after each intervention Positive and Negative Affect Schedule, PTh and PTol (cold water emersion test) were assessed. Results: Results indicate an increase of the Positive Affect Scale (high: 26.7 ± 9.0 vs. 32.9 ± 7.1, p