The Effect of Heat Exposure on the Inflammatory Response during Exercise

The Effect of Heat Exposure on the Inflammatory Response during Exercise Jessica Sankovic1, Kylene Boka1, Jeremiah A. Vaughan1,2, Brittany N. Followay1,3, Ellen L. Glickman1, Adam R. Jajtner1 1Exercise Physiology Program, Kent State University, Kent, OH 2Department of Human Performance, Sport and Health, Bemidji State University, Bemidji, MN 3Exercise Science Department, Ripon College, Ripon, WI PURPOSE: Examine circulating levels of IL-6, IL-10, IL-1ra and TNF-α during exercise and heat exposure. METHODS: Twelve college-aged men completed three experimental conditions; VO2max test and cycling trials in 22°C (MT) and 35°C (HT). Cycling trials consisted of 60 minutes at 60% VO2max, 15-minute rest, time to exhaustion at 90% VO2max, and 60-minute recovery. Blood was analyzed for concentrations of IL-6, IL-10, IL1-ra and TNF-α before exercise (Pre), after 60% VO2max (60), 90% VO2max (90), and recovery (Rec). Data were analyzed with repeated-measures ANOVA. RESULTS: An interaction was observed for IL-6 (F=5.883, p=0.003, ηp2= 0.395), with significant increases from Pre to 60 to 90, and return to baseline at Rec for both conditions (pp2=0.340), with increases from Pre to 90 for both conditions (pp2=0.636) and condition (F=9.539. p=0.011, ηp2=0.488) were observed for IL-1ra, with greater IL-1ra concentrations in HT than MT (p=0.011), and increases from Pre, 60, and 90 to Rec (pp2=0.337) was observed, with increases from PRE in HT (pCONCLUSIONS: The increase of these cytokines during exercise indicates activation of the inflammatory response. The response of IL-6, IL-10, and IL-1ra to heat exposure suggests the exercise-induced anti-inflammatory response is greater than a pro-inflammatory response to the heat.