The effects of acute moderate exercise on leukocyte and lymphocyte subpopulations.

The extent and duration of changes in circulating leukocyte and lymphocyte subpopulations, cortisol, and catecholamines were examined in 12 women who walked 45 min at 60% VO2max in a laboratory setting. A two-factor, 2 x 6 design with repeated measures on both factors was utilized. The first factor was condition (exercise and rest), and the second factor was time (six points of measurement over a 24-h period), with treatment order counterbalanced. The 45-min walk, in comparison with rest in a seated position, was associated with a significant but moderate leukocytosis and lymphocytosis immediately following the walk. The leukocytosis was still evident after 3 h of recovery and was primarily due to a neutrophilia. The change in lymphocyte count, relative to baseline levels and the control condition, lasted less than 1.5 h, with an increase in the natural killer (CD16 and/or CD56) and cytotoxic T cell component (CD3 and CD16 and/or CD56) (NKCT) representing approximately two-thirds of the lymphocytosis and T cells (CD5) the other third. A significant decrease in the CD4:CD8 ratio was seen, with cytotoxic/suppressor (CD8) cells increasing and helper/inducer (CD4) cells demonstrating little change in comparison with baseline. This seems to have been due to a subpopulation of CD8 (low density antigen) cells, probably natural killer cells. The 45-min walk had no effect on plasma cortisol and epinephrine levels relative to the rest condition but was associated with a moderate increase in norepinephrine.(ABSTRACT TRUNCATED AT 250 WORDS)