Temporal summation of heat pain modulated by isometric exercise

BACKGROUND: Little is known about the effects of isometric exercise on temporal summation of heat pain. Thus, the purposes of study 1 and study 2 were to examine the influence of exhaustive and non-exhaustive isometric exercise on temporal summation of heat pain in men and women. METHODS: Forty-four men and 44 women (mean age = 20 years) completed an informed consent document and a packet of questionnaires. Ten heat pulses were applied to the thenar eminence of the dominant hand using a standardized temporal summation protocol. Participants rated the intensity of the heat pulses using a 0-100 pain rating scale before and following isometric exercise consisting of squeezing a hand dynamometer at 40% of maximal voluntary contraction (MVC) to exhaustion (exhaustive exercise, study 1) and at 25% MVC for 3 min (non-exhaustive exercise, study 2). Muscle pain and perceived exertion were rated every 30 s during exercise using validated rating scales. The data were analysed with repeated measures analysis of variance. RESULTS: The results indicated there were no sex differences (p > 0.05) in time to exhaustion (study 1), muscle pain or perceived exertion (studies 1 and 2). There was a significant reduction (p < 0.05) in temporal summation ratings following isometric exercise for men and women in both study 1 and study 2. CONCLUSION: It is concluded that exhaustive and non-exhaustive isometric exercise significantly reduced temporal summation of heat pain in men and women.