In order to clarify the relationship between acute physical exercise and immunity, the numbers of overall leucocytes, lymphocytes and neutrophils, the concentrations of immunoglo-bulins and complements, the ratios of lymphocyte subsets (OKT 3, 4, 8, Leu 7, OKIa 1) and the levels of lymphocyte transformation response to PHA were measured in nine untrained male subjects (18-22 years old) before, immediately after, along with 24 and 72 hours after acute physical exercise at 50% of VO₂max for 2 hours. Before exercise all components were within normal range. Exercise produced a significant rise in the number of leucocytes and neutrophils overall. The response of lymphocytes to PHA immediately after exercise was significantly lower than before, or 24 hours or 72 hours after exercise.
There was no change in the number of lymphocytes, or in the concentration of immunoglo-bulins and complements before and after exercise. Likewise the ratios of lymphocyte subsets also remained unchanged.
From these results, it can be concluded that acute physical exercise by untrained subjects is one kind of physical stressor and can contribute to T cell dysfunction.