Changes in Lymphocyte Subpopulations After Prolonged Exercise*

Abstract

In order to assess the changes in the cellular immune system, 27 healthy male subjects were selected who participate in leisure-time sports and in whom measurements of the lymphocyte subsets in venous blood were carried out before and after a standardized endurance exercise test (E I, 60 minutes in length, intensity: 63% of maximum performance). The percentages of the following parameters were measured: total T-lymphocytes , B-lymphocytes and O-lymphocytes as well as T₄-lymphocytes (helper T-lymphocytes, CD4 +) and T₈-lymphocytes (cytotoxic/sup-pressor T-lymphocytes, CD8 +). In a subgroup consisting of 8 subjects, the parameters indicated above were measured again 24 hours following E. In order to check the reproducibility of the findings, the endurance exercise test was repeated 21/2 weeks later(E II).

At the end of E, the T-lymphozytes had decreased significantly in comparison to the initial value, whereas O-lymphocytes increased by the same amount. In addition, helper T-lymphocytes were decreased and cyto-toxic/suppressor cells were increased significantly. All changes had been reversed 24 hours following E. Between E I and E II there was no difference with respect to the changes in lymphocytes and their subpopulations.

The data suggest that acute prolonged exercise influences the cellular immune system. The question as to the degree to which these immunological changes can be equated with a suppression of the cellular immune system and cause and enhanced susceptibility to infections in high-performance athletes cannot be conclusively answered on the basis of the present data.

Key words

Lymphocyte subsets - cellular immune system - prolonged exercise - immunosurveillance