Int J Sports Med 1995; 16(7): 466-474
DOI: 10.1055/s-2007-973039

© Georg Thieme Verlag Stuttgart · New York

Strenuous Exercise and Immunological Changes

A Multiple-Time-Point Analysis of Leukocyte Subsets, CD4/CD8 Ratio, Immunoglobulin Production and NK Cell ResponseP. N. Shek1 , 2 , 3 , B. H. Sabiston1 , A. Buguet4 , M. W. Radomski1 , 2
  • 1Defence and Civil institute of Environmental Medicine, North York, Ontario, Canada
  • 2Programme in Exercise Sciences, Graduate Department of Community Health, and
  • 3Department of Clinical Biochemistry, Faculty of Medicine, University of Toronto, Canada
  • 4Centre de Recherches du Servicé de Sainte des Armées Emile Pardé, La Tranche, France
Further Information

Publication History

Publication Date:
09 March 2007 (online)

This study was designed to examine the impact of exhaustive endurance exercise on a number of immune parameters of physically fit male subjects (VO2max 66.5 ± 5.3 ml/min/kg) who performed treadmill exercise at 65 % of their /O2max for 120 min. Serial blood samples were taken before, during and after exercise and changes in leukocyte and lymphocyte subset concentrations; immunoglobulin production in vitro; and natural killer (NK) cell response were measured. The exercise regimen was found to induce the well-known phenomenon of leukocytosis which consisted primarily of a granulocytosis and lymphocytosis. Among the lymphocyte subsets, peripheral pan T cells (CD3+) as well as helper (CD4+) and suppressor (CD8+) T cells were found to be elevated. A relatively smaller increase in CD4+ than CD8+ cells resulted in depressed CD4/CD8 ratios throughout the exercise period. After exercise, T cells declined progressively and, 2 h post-exercise, were less than 60 % of their pre-exercise level. In contrast, the CD4/CD8 ratio demonstrated a progressive increase, thus representing a reversal in the pattern observed during exercise and a trend towards an elevated ratio during recovery. B cells (CD19+) were relatively unaffected by exercise, although IgM production by pokeweed mitogen-stimulated lymphocytes obtained from blood samples after 120 min of exercise was significantly depressed. NK cells were affected dramatically by exercise. Both CD16+ cell numbers and NK cytotoxicity were increased during exercise, followed by a persistent depression in the post-exercise period. The strenuous exercise induced a profound effect on NK cells as evidenced by a 40 % depression of the NK cell count for as long as 7 days after the cessation of exercise. Our results provide direct kinetic evidence demonstrating that exhaustive exertion alters both lymphocyte distribution pattern and effector function, suggestive of possible exercise-induced immune compromise, particularly in the post-exercise recovery period.