THE ACUTE IMMUNE-RESPONSE TO EXHAUSTIVE RESISTANCE EXERCISE

Ten young male adults (mean age 46.9 +/- 1.2 yrs) with 9.2 +/- 1.4 yea rs of weight training experience and the ability to parallel squat at least 1.5 times their body mass were selected as subjects. The exercis e session consisted of sets of 10 repetitions at 65% 1-RM of the paral lel leg squat, with a cadence of one rep every 6 sec and 3 min rest be tween sets, to muscular failure. The average subject lifted a total of 9711 +/- 1576 kg during 98 +/- 14 reps for a total work output of 72. 5 +/- 10.5 kJ before muscular failure occurred. Mean oxygen consumptio n during exercise was 1.58 +/- 0.06 l/min at 42.5 +/- 2.0% peak VO2. A strong leukocytosis, lymphocytosis, and lymphocytopenia, similar to w hat has been reported following high-intensity cardiorespiratory exerc ise, were measured following leg squat exercise. Con A-stimulated lymp hocyte proliferation (unadjusted) rose 50% above preexercise levels (p = 0.07), but when these data were adjusted on a per T cell (CD3(+)) b asis, no change from rest was observed. Natural killer cell cytotoxic activity (NKCA), when adjusted on a per NK cell (CD56(+)) basis, was d ecreased about 40% below preexercise levels for at least 2 h post-exer cise. No significant increase in cortisol was seen after exercise, alt hough norepinephrine and epinephrine increased moderately (465% and 13 3%, respectively), immediately following exercise. The data demonstrat e that leg squat exercise to muscular failure results in a very simila r immune response to that associated with intense endurance exercise, despite a lower mean oxygen consumption and only a moderate hormonal r esponse.