The effects of a single session of moderate intensity (65% VO(2)max) aerobic exercise expending 500 kcal of energy on serum lipid and lipoprotein-cholesterol concentrations and the electrophoretic characteristics of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particles were determined in 11 sedentary, eumenorrheic, premenopausal women immediately prior to, and 24 and 48 h following exercise. Repeated measures analysis of variance revealed significant reductions in triglyceride (25.0%), HDL-cholesterol (10.9%), and HDL(3)-cholesterol (11.9%) concentrations at 48 h post-exercise. Despite these changes in lipid and lipoprotein-cholesterol concentrations, no significant changes were observed in peak LDL or HDL particle sizes or in the distribution of cholesterol within the LDL and HDL subfractions. Accordingly, it appears that a single session of moderate intensity aerobic exercise expending 500 kcal (2,092 kJ) of energy promotes reductions in triglyceride, HDL-C, and HDL(3)-C concentrations without concomitantly affecting the electrophoretic characteristics of LDL and HDL particles in this sample of women.

A clear picture of lipoprotein metabolism is essential for understanding the pathophysiology of atherosclerosis. Many students are taught that low-density lipoprotein-cholesterol is "bad" and high-density lipoprotein-cholesterol is "good." This misconception leads to students thinking that lipoproteins are types of cholesterol rather than transporters of lipid. Describing lipoproteins as particles that are composed of lipid and protein and illustrating the variation in particle density that is determined by the constantly changing lipid and protein composition clarifies the metabolic pathway and physiological function of lipoproteins as lipid transporters. Such a description will also suggest the critical role played by apolipoproteins in lipid transport. The clarification of lipoproteins as particles that change density will help students understand the nomenclature used to classify lipoproteins as well.

The purpose of this investigation was to determine the independent and combined effects of aerobic exercise and omega-3 fatty acid (n-3fa) supplementation on lipid and lipoproteins. Sedentary, normoglycemic, nonsmoking men (n = 11) were assigned to perform rest and exercise before and during n-3fa supplementation. Exercise consisted of 3 consecutive days of treadmill walking at 65% maximum O(2) consumption for 60 min. Supplementation consisted of 42 days of 4.55 g/day of n-3fa. A two-way factorial ANOVA with repeated measures revealed significant reductions in total cholesterol (P = 0.001, -9.2%) and triglyceride (P = 0.007, -32.4%) concentrations postexercise. In addition, exercise increased LDL peak particle size (P = 0.001) from 26.2 to 26.4 nm, but not HDL size. The n-3fa supplementation resulted in a significant shift in the distribution of HDL-cholesterol (HDL-C) carried by HDL(2b+2a) (P = 0.001, 14.2%) and HDL(3a+3b) (P = 0.001, -22.8%), despite no significant changes in lipid and lipoprotein-cholesterol concentrations. The majority of the shift in HDL-C was noted in HDL(2b) (P = 0.001, 20.9%) and HDL(3a) (P < 0.001, -31.0%) particles. There were no combined effects of exercise and n-3fa supplementation on lipids and lipoproteins. Three consecutive days of aerobic exercise reduced triglyceride and total cholesterol concentrations with a concomitant increase in LDL peak particle size. In contrast, n-3fa supplementation shifted HDL-C from HDL(3) particles to HDL(2) particles, despite no significant changes in HDL(2)-C and HDL(3)-C concentrations. Exercise and n-3fa supplementation do not synergistically improve serum lipids and lipoproteins, but rather independently affect the metabolism of lipids and lipoproteins.

The purpose of the study was to determine the efficacy of a low-volume, moderate-intensity bout of resistance exercise (RE) on glucose, insulin, and C-peptide responses during an oral glucose tolerance test (OGTT) in untrained women compared with a bout of high-volume RE of the same intensity. Ten women (age 30.1 ± 9.0 years) were assessed for body composition, maximal oxygen uptake, and 1-repetition maximum (1RM) before completing 3 treatments administered in random order: 1 set of 10 REs (RE1), 3 sets of 10 REs (RE3), and no exercise (C). Twenty-four hours after completing each treatment, an OGTT was performed after an overnight fast. Glucose area under the curve response to an OGTT was reduced after both RE1 (900 ± 113 mmol·L(-1)·min(-1), p = 0.056) and RE3 (827.9 ± 116.3, p = 0.01) compared with C (960.8 ± 152.7 mmol·L(-1)·min(-1)). Additionally, fasting glucose was significantly reduced after RE3 (4.48 ± 0.45 vs. 4.90 ± 0.44 mmol·L(-1), p = 0.01). Insulin sensitivity (IS), as determined from the Cederholm IS index, was improved after RE1 (10.8%) and after RE3 (26.1%). The reductions in insulin and C-peptide areas after RE1 and RE3 were not significantly different from those in the C treatment. In conclusion, greater benefits in glucose regulation appear to occur after higher volumes of RE. However, observed reductions in glucose, insulin, C-peptide areas after RE1 suggest that individuals who may not well tolerate high-volume RE protocols may still benefit from low-volume RE at moderate intensity (65% 1RM).

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