The Effect of Acute Aerobic Exercise on Measures of Stress and Inflammation in Healthy Young Adults

Introduction: While the effects of long-term measures of inflammation and stress are well studied, less is known about the effects of an acute exercise challenge on exercise in young healthy individuals. Methods:  This was a randomized crossover design (mean age = 19.25, SD = 1.45) that measured biomarkers of stress (cortisol and salivary alpha amylase, sAA) and inflammation (IL-1β, CRP) in an exercise and control condition. In the exercise condition, participants walked or ran on a treadmill at 75-85% of their maximum heart rate for 40 minutes. Under the control condition, participants stood for 40 minutes to control for orthostatic effects. Biomarkers were quantified from saliva collected before, 1 minute after, and 45 minutes after the exercise and control condition. Results: The change in biomarkers from baseline values (+1 min and + 45 min) between exercise and control conditions showed that compared to the control condition, the acute exercise bout significantly increased sAA CRP at +1min at +45 min and in IL-1β +45 min. Cortisol levels significantly decreased at both time points in the control condition Conclusions: Ultimately, the results of this study show how small and realistically achievable amounts of exercise can acutely strengthen the body’s physiological responses to immune challenges.