Effect of exercise on blood lipid constituents and aerobic capacity of fire fighters.

The effect of 32 weeks of exercise training, at moderate intensity, on serum lipids, lipoproteins, aerobic power, anaerobic threshold, body composition, and coronary heart disease (CHD) risk factors was examined in 38 male fire fighters (mean +/- SD 42.7 +/- 6.4 yr). Exercise training included cycling, rowing, walking, jogging, running, and circuit weight training 3 d/wk, 30 min/session at 350 to 450 kcal/session. Fasting blood samples collected pre- and post-training were assayed for triglyceride (TG), total cholesterol (CHOL), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), and high-density lipoprotein (HDL-C). Maximum aerobic power (VO2max) was measured during a treadmill test. Anaerobic threshold (AT) was predicted by observing the onset of a systematic increase in VE/VO2 without a concomitant increase in VE/VCO2. Body composition was determined via underwater weighing and skinfold measurements. There were no significant differences in CHOL, CHOL/HDL-C ratio, or LDL-C/HDL-C ratio. Only the AT, HDL-C, VO2max, and CHD risk levels changed significantly (P less than 0.05). Cholesterol, LDL-C, VLDL-C and triglycerides were linearly related to body fat. Maximal oxygen uptake and HDL-C were inversely related to body fat. It was concluded that moderate exercise intensity can yield a marked increase in AT, VO2max, and HDL-C while not significantly affecting the CHOL level. The findings lend support to the contention that risk reduction for CHD lies on a continuum.