Exercise-induced lipid mediator inflammatory signalling in male recreational runners versus untrained males considering potential modulating factors

MSc (Nutrition), North-West University, Potchefstroom Campus Background: Resistance exercise can cause inflammation and it is known that inflammation is closely related to oxidative stress. Oxidative stress can be defined as an imbalance between free radicals and anti-oxidative mechanisms, or the excess of reactive oxygen species (ROS). The body reacts to injury or infection, as well as to excessive ROS production during exercise, with an inflammatory response. A complex network of lipid mediators regulates the inflammatory response. Lipid mediators are also known as eicosanoids and can regulate inflammation by eliciting either a pro-inflammatory or anti-inflammatory response. There is still little evidence to the question as to whether there is a difference in pro-inflammatory lipid mediator status between recreational runners and untrained individuals, and which factors can modulate this response. Objectives: The aim of the study is to compare exercise-induced lipid mediator inflammatory signalling in male recreational runners with untrained males considering potential modulating factors such as fatty acid and antioxidant status, as well as antioxidant nutrient intake. Study design: This was a cross-sectional study on healthy, male, untrained individuals (n=20) and recreational runners (n=20). A medical screening was done (blood pressure, heart rate, temperature and fingerprick blood glucose). The participants’ height and weight were measured, and a three-day dietary record was administer red. Blood samples were collected before both groups participated in resistance exercises at 80% of their 1 repetition max and immediately on completion of that exercise challenge, as well as 1, 2, 24 and 72 hours after cessation of the exercise. Results: The runners were taller and heavier than the non-runners (P = 0.018 and P = 0.04, respectively). Runners did significantly more running exercise than non-runners (P < 0.001). Eicosapentaenoic acid (EPA), monounsaturated fatty acids (MUFA), n-3 polyunsaturated fatty acids (PUFA) and n-3 long chain (LC) PUFA were higher in the runner group compared to the non-runner group (P = 0.001, P = 0.045, P = 0.040 and P = 0.041). On the other hand, the total n-6:n-3 PUFA and the n-6:n-3 LCPUFA ratios were higher in the non-runner group compared to the runner group (P = 0.032 and P = 0.031) . The runners’ linoleic acid, vitamin C and Vitamin E intake were higher than the intake of the non-runners (P = 0.035; P = 0.028 and P = 0.013), respectively. There was a significant difference in response over time in the runners compared to the non-runners for 5-HETE and 12-HEPE (P = 0.005 and 0.008). When adjusted for BMI and diet, 5-HETE, 15-HETE and 8-HETE showed a significantly different response over time between the two groups (P = 0.012, P = 0.033, P = 0.016), respectively. There was also a significant different response for 8-HETE, 12-HEPE and 18-HEPE adjusted for BMI and oxidative stress (P = 0.041, P = 0.059 and P = 0.085), respectively. When adjusting for BMI, diet and oxidative stress this resulted in a significant difference between the groups for 5-HETE (P = 0.016) and 8-HETE (P = 0.043). Conclusion: This study showed that pro- and anti-inflammatory lipid mediator responses are different among runners and non-runners and are influenced by BMI, vitamin C and E intake, the n6:n3 LCPUFA status ratio and endogenous oxidative stress adaptation. Masters