Effects of high- and low-intensity exercise training on aerobic capacity and blood lipids

Abstract

Sixteen non-obese, non-smoking males, ages 20-30 yr, were assigned to 1 of 2 training groups, exercising on a cycle ergometer 3 d[day]/wk for 18 wk: high-intensity (H; N = 7; 80-85% .ovrhdot.VO2 max, [maximum O2 uptake] 25 min/session) or low-intensity (L; N = 9; 45% .ovrhdot.VO2 max, 50 min/session). Data were obtained at 3-wk intervals for .ovrhdot.VO2 max, body weight, percent body fat and 12-h fasting blood levels of cholesterol (CHOL), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). The average post-training increase in .ovrhdot.VO2 max for group H (0.56 .cntdot. min-1, 8.5 ml/min per kg) was not significantly (P > 0.05) greater than for group L (0.45 l .cntdot. min-1, 6.5 ml/min per kg). Significant reductions in percent body fat occurred in both groups, amounting to an average fat loss of .apprx. 1.35 kg. No statistically significant changes in CHOL, TG, HDL-C, LDL-Ch, CHOL/HDL-C, or HDL-C/LDL-C occurred in either group. Changes in HDL-C after 18 wk of training were inversely correlated (r = -0.57, P < 0.05) with pre-training levels. The minimum exercise training-intensity threshold for improving aerobic capacity is at least 45% .ovrhdot.VO2 max, 18 wk of high- or low-intensity exercise training is ineffective in significantly altering CHOL, TG, HDL-C, LDL-C CHOL/HDL-C and HDL-C/LDL-C in young male subjects with low blood lipid levels; exercise training-induced changes in HDL-C are dependent on initial pre-training levels.