Downloaded from http://journals.lww.com/nsca-jscr by BhDMf5ePHKbH4TTImqenVAHxkFJp/XpPk1L/H3vMGwqMxG9jwOd8eJPG+b4DlKuAX44qu/vwzmc= on 07/30/2018 THE EFFECT OF A HIGH-INTENSITY INTERVAL TRAINING PROGRAM ON HIGH-DENSITY LIPOPROTEIN CHOLESTEROL IN YOUNG MEN DANLADI I. MUSA, 1 SAMUEL A. ADENIRAN, 2 A. U. DIKKO, 3 AND STEPHEN P. SAYERS 4 1 Human Performance Laboratory, Physical and Health Education Unit, Benue State University, Makurdi, Nigeria; 2 Exercise Physiology Laboratory, Institute of Physical and Health Education, Obafemi Awolowo University, Ile-Ife, Nigeria; 3 Biochemistry Laboratory, Department of Physiology, Bayero University, Kano, Nigeria; and 4 Neuromuscular Research and Rehabilitation Laboratory, Department of Physical Therapy, University of Missouri, Columbia, Missouri ABSTRACT Musa, DI, Adeniran, SA, Dikko, AU, and Sayers, SP. The effect of a high-intensity interval training program on high-density lipoprotein cholesterol in young men. J Strength Cond Res 23(2): 587–592, 2009—This study examined the impact of an 8-week program of high-intensity interval training on high- density lipoprotein cholesterol (HDL-C), total cholesterol (TC), and the atherogenic index (TC/HDL-C) in 36 untrained men ages 21–36 years. Participants were randomly assigned to an interval training group (n = 20) or a control group (n = 16). Participants in the experimental group performed 3.2 km of interval running (1:1 work:rest ratio) 3 times a week for 8 weeks at an intensity of 90% of maximal heart rate (~423 kcal per session). Results indicated significant pre- to posttraining changes in HDL-C (1.1 vs. 1.3 mmolÁL 21 , p , 0.0001) and TC/ HDL-C (3.8 vs. 3.1, p , 0.0001) but no significant changes in TC (3.9 vs. 3.8 mmolÁL 21 , p . 0.05) with interval training. It was concluded that an 8-week program of high-intensity interval training is effective in eliciting favorable changes in HDL-C and TC/HDL-C but not TC in young adult men with normal TC levels. Our findings support the recommendations of high- intensity interval training as an alternative mode of exercise to improve blood lipid profiles for individuals with acceptable physical fitness levels. KEY WORDS atherogenic index, cardiovascular disease risk, coronary heart disease, exercise training, total cholesterol INTRODUCTION H igh-density lipoprotein cholesterol (HDL-C) is considered the most potent independent risk factor for coronary heart disease (CHD) and is inversely correlated with CHD. High levels of HDL-C may have a protective role against coronary atherosclerosis (24) because of its role as a lipid scavenger involved in the reverse transport of cholesterol from the peripheral vascular compartment and tissues to the liver for excretion as bile. Though the mechanism for the beneficial roles of HDL-C has yet to be completely elucidated, it is thought that lecithin:cholesterol acyltransferase (L-CAT) and hepatic lipase (HL) facilitate the roles of HDL-C in reverse cholesterol transport from the arterial wall (20,33). Endurance exercise training, characterized by continuous activity at moderate exercise intensity, demonstrates signif- icant increases in HDL-C in both men and women after a period of training, typically 20–30% for endurance athletes compared with inactive controls (8,15). Furthermore, there seems to be a dose-response relationship between the amount of exercise performed and the increase in HDL-C (34) as well as the intensity of the exercise and increase in HDL-C (26). Despite the well-known benefits of aerobic training on blood lipid profiles, the effect of other modes of physical training on blood lipid profiles has not been adequately explored. Interval training, for example, which alternates between high-intensity work and periods of rest, is one of the most widely used methods of physical training in young men and women. Interval training studies using typical work:rest intervals (1:3 or 1:2.5) have shown little effect on blood lipid profiles (10,19,27), but it is not clear whether longer work intervals at high intensity, with prolonged periods of continuous physical activity, would have more favorable effects on blood lipid profiles. The purpose of the present study was to determine whether an 8-week program of high-intensity interval training with a longer work:rest interval would significantly elevate HDL- C and reduce the total cholesterol (TC) and atherogenic index Address correspondence to Stephen P. Sayers, sayerss@missouri.edu. 23(2)/587–592 Journal of Strength and Conditioning Research Ó 2009 National Strength and Conditioning Association VOLUME 23 | NUMBER 2 | MARCH 2009 | 587 Copyright © . National Strength and Conditioning Association. Unauthorized reproduction of this article is prohibited