Aerobic exercise, training and modulation of the human immune system

Abstract

This study has examined the effects of aerobic exercise and training on immune cell distribution and function. An experimental model of treadmill running was developed to examine, independently, the differential effects of metabolic and mechanical stress on immunity. Uphill treadmill running was used to elicit metabolic stress and downhill treadmill running was used to elicit mechanical stress. The uphill running was characterised by significantly higher (p<0.05) oxygen uptake than both downhill and level running, while downhill running was associated with significant (p<0.05) elevations in systemic and subjective markers of muscle damage and soreness. Uphill running (metabolic stress) also resulted in a significant increase in the number of circulating leucocytes and subclasses of lymphocytes, moncytes and granulocytes, associated with intensity-dependent elevations in the plasma concentration of adrenaline and cortisol. The metabolic stress of exercise appeared to elicit greater elevations in the physiological parameters examined than did mechanical stress.