Supervisors info:
Γελαδάς Ν., Καθηγητής, ΣΕΦΑΑ, ΕΚΠΑ
Μπογδάνης Γ., Καθηγητής, ΣΕΦΑΑ, ΕΚΠΑ
Κοσκολού Μ., Αν. Καθηγήτρια, ΣΕΦΑΑ, ΕΚΠΑ
Summary:
Introduction: Exercise in the heat is a severe stressor for the body. Athletic performance in endurance activities in a hot enviroment is related to the thermal stress that the athlete receives and his ability to regulate his temperature in order to maintain homeostasis. Strong evidence shows that there is an upper limit of the core temperature than an athlete can reach and at that point fatigue occurs and exercise stops. According to this, if core temperature is remained at lower levels athletic performance is improved and exercise duration increases. Capsaicin, a substance of chilly peppers it is well known for its impact on thermoregulatory responses, the activation of heat loss mechanisms and the lowered thermal stress and core temperature. Moreover, capsaicin has analgetic effects and research shows that it reduces the rating of perceived exertion, improving maximal exercise performance. However, there is no data examining the effects of capsaicin on athletic performance in the heat.
Purpose: To evaluate the effect of capsaicin application to the skin in endurance performance in the heat and in maximal exercise until exhaustion in thermoneutral enviroment.
Methods: 12 endurance athletes, of age 38.5±3, participated in the study. Experimental design consisted of 4 visits in the laboratory in different days. In 2 visits the aerobic power (VO2max) with (CA) and without (NCA) application of capsaicin in thermoneutral enviroment (22-24°C) were assesed, and in 2 other visits the effect of capsaicin in endurance performance in the heat (30°C) was tested, in a randomized and counterbalanced order. Exercise in heat was performed for 30 minutes on a cycle ergometer at a constant power 5% less of the ventilatory threshold followed immediately by a test until exhaustion at 120% PPO (Peak Power Output). Before and after each experiment maximal voluntary contractions were performed. Throughout the experiments the cardiovascular, respiratory and thermoregulatory parameters were recorded. 2-Way ANOVA with repeated measures (Capsaicin X Time) was conducted. The level of significance was set at p<0.05.
Results: At the VO2max test capsaicin (CA) increased significantly the maximal oxygen uptake (VO2max) (p<0,05) and maximal ventilation (VEmax) (p<0,05) compared with NCA condition. Moreover, in CA condition there was a significant increase in thermal sensation (p<0,05) and in Rating of Perceived Exertion (RPE) (p<0,05) compared with NCA condition. There was no difference in PPO and in any cardiovascular parameter. In the heat test during the 30 minutes trails there was a significant increase (p<0,05) in heart rate (HR), oxygen uptake (VO2), RPE, and a significant decrease (p<0,05) in systolic pressure for both groups, CA and NCA, without differences between the two conditions. Thermal sensation was increased (p<0,05) in CA condition compared to the NCA condition. There was no difference in time to exhaustion and in thermoregulatory response between the two conditions.
Conclusions: Capsaicin application to the skin had no effect on neither maximal exercise performance in thermoneutral environment nor on endurance exercise in the heat. Capsaicin had also no effect on thermoregulatory responses.
