The effect of acute exercise on natural killer-cell activity of trained and sedentary human subjects

The effect of acute exercise on natural killer (NK) activity and on the distribution of phenotypic characteristics of peripheral blood lymphocytes was examined. Trained and sedentary individuals underwent a standard progressive exercise test on a cycle ergometer using an incremental work load of 15 W (90 kpm), increased every minute. Each subject was encouraged to exercise to exhaustion, and total ventilation and mixed expired O2 and CO2 were measured every 30 sec. All subjects reached the "anaerobic" threshold as judged by the deflection of ventilation at a work load near VO2max. NK activity against K562 reached maximum levels immediately after exercise, dropped to a low point 120 min later, then slowly came back to preexercise levels within 20 hr. No significant differences were observed between the trained and the sedentary groups. Furthermore, immediately after exercise the proportion of OKT-3+ and OKT-4+ cells was reduced by 29.8 +/- 3.6 and 33.6 +/- 5.4%, respectively; the percentage Leu-7+ and Leu-11a+ cells was increased by 53.9 +/- 1.7 and 57.3 +/- 2.9%, respectively. The percentage OKT-8+ cells was not significantly altered. When the percentage binding of effector to target cells was examined, it was highest at 0 min post-exercise (19 +/- 6.2%) and lowest at 120 min postexercise (7 +/- 3.9%), but the absolute number of NK cells remained unchanged. The source of serum used in the lytic assay had no effect on the NK activity, as fetal calf serum and autologous sera drawn at different time intervals during exercise gave similar results.(ABSTRACT TRUNCATED AT 250 WORDS)