The Effect of Heat Exposure on the Inflammatory Response during Exercise

Jessica Sankovic¹, Kylene Boka¹, Jeremiah A. Vaughan^1,2, Brittany N. Followay^1,3, 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, η_p²= 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, η_p²=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.