Eur J Appl Physiol (1993) 67:226-230 European Journal of Applied Physiology and Occupational Physiology @ Springer-Verlag 1993 Effects of exercise cessation on lipids and lipoproteins in distance runners and power athletes Tibor Hortobdgyi l, Joseph A. Houmard 1, Richard G. Israel 1, John W. Carpenter 2, Judy Heath 2, and Hisham A. Barakat 2 Human Performance Laboratory and 2 Department of Biochemistry, School of Medicine, East Carolina University, Greenville, NC 27858, USA Accepted May 11, 1993 Summary. The purpose of this study was to determine the effects of short-term exercise cessation on lipid and lipoprotein profile and insulin sensitivity in highly trained runners (n = 12; mean age 19.9 years) and pow- er athletes (n = 12; mean age 24.4 years). Following 14 days of exercise cessation, running time to exhaustion and maximal oxygen uptake decreased by 9.2% and 4.8% (P< 0.05) in the runners, while in the power ath- letes one repetition maximum squat and bench press did not change (P>0.05). No changes occurred in body composition. Data from a 2-h oral glucose toler- ance test revealed an impairment of the glycemic state in all athletes (P < 0.05). In contrast, exercise cessation did not significantly (P>0.05) alter plasma levels of cholesterol, triglycerides, and low density (LDL) and high density lipoprotein (HDL). No changes were ob- served in HDL2, HDL2b, and HDL3 subfractions, LDL diameter, and qualitative LDL pattern (P>0.05). These data thus suggest that despite a decrease in in- sulin sensitivity, short-term exercise cessation, inde- pendent of exercise mode, was insufficient to alter plasma lipid and lipoprotein profiles in well-trained athletes. Key words: Detraining - Insulin sensitivity - Coronary heart disease Introduction High levels of plasma total cholesterol (TC), triglycer- ide (TG), and low density lipoprotein (LDL), and low levels of high density lipoprotein (HDL) are associated with coronary heart disease (CHD; Abbott et al. 1988). In addition, HDL2 subfraction is inversely, while LDL particle diameter is positively correlated with CHD. Prior reports have also shown that particularly endu- rance training favorably alters these lipids and lipopro- Correspondence to: T. Hortobfigyl teins and may reduce CHD risk (Dufaux et al. 1982; Haskell 1986). In some studies similar positive effects have been demonstrated following resistive exercise training (Hurley 1989). Both endurance (Wallberg- Henriksson 1992) and resistive exercise (Miller et al. 1984) have been shown to improve insulin sensitivity. Thus, the positive effects of exercise training on lipids and lipoproteins may be associated with improvements in insulin sensitivity (Barakat et al. 1990). In contrast, detraining impairs insulin sensitivity in endurance and power athletes (Houmard et al. 1992). However, it is unclear how short-term exercise cessation would in- fluence lipids and lipoproteins and whether such changes would occur in a coordinated fashion with a reduction in insulin sensitivity. Therefore, the purpose of the present study was to evaluate the effects of short-term exercise cessation on plasma lipids and lipo- proteins and insulin sensitivity in well-trained runners and power athletes. Methods Subjects. Twenty-four athletes (12 long-distance runners and 12 power athletes) volunteered as subjects. Prior to any testing, they signed an informed consent form that was approved by the Uni- versity's Human Subject Review Board. The runners, nine men and three women (all Caucasian), were members of the Univer- sity cross-country team and ran [mean (SD)] 65 (14) and 80 (20) km.week -1, respectively. All subjects had trained regularly for 2-8 years. The power athletes (five Caucasians and seven Afro-Ameri- cans) had a weight lifting experience of 8.1 (1.61) years. Eight of these men were former Division I American football players, who were exclusivelyweight trained, and four were power-lifters who worked out 3-4 times per week for about 1.5 h, performing 2-5 sets of 1-12 repetitions of 70-100% of maximal weights for 5-7 upper and lower body exercises. Table 1 shows the descrip- tive data of the subjects. Design All subjects were tested during normal training and following 14 days of exercise cessation. During normal training, performance