Effect of exercise training on glucose tolerance, in vivo insulin sensitivity, lipid and liproprotein concentrations in middle-aged men with mild hypertriglyceridemia

Abstract

The effects of 9 weeks of aerobic exercise training with maintenance of stable body weight upon insulin sensitivity and upon glucose, lipid, and lipoprotein concentrations were studied in 10 middle-aged men with mild hypertriglyceridemia. Following training, mean maximum oxygen consumption improved from 33.5 +/- 1.9 to 39.3 +/- 1.9 mL/kg/min (means +/- SEM), (P less than 0.01). Glucose concentrations, both fasting and during oral glucose tolerance testing, remained stable but both fasting insulin concentrations and insulin responses to oral glucose decreased (P less than 0.1 and less than 0.01, respectively). In vivo insulin sensitivity improved 25 +/- 6.1% (P less than 0.01) following training. Exercise training resulted in decreases in fasting serum triglyceride concentrations from 203 +/- 12.6 to 126 +/- 9.0 mg/dL (P less than 0.01), primarily as a result of the reduction in VLDL-triglycerides (P less than 0.01). The magnitude in percentage decrease of VLDL-triglycerides was found to be significantly correlated (r = 0.71, P less than 0.05) with the magnitude in percent increase in max VO2. Serum cholesterol levels declined from 211 +/- 8.9 to 193 +/- 11.9 mg/dL (P less than 0.01), and the ratio of HDL-cholesterol to total cholesterol was improved. This study demonstrates that exercise training at a level of intensity feasible for many middle-aged men has beneficial effects on several factors that have been associated with an increased risk of cardiovascular disease.

Low‐intensity endurance exercise training, plasma lipoproteins and the risk of coronary heart disease

“…Low-intensity endurance exercise training has also been frequently reported to induce favourable changes in plasma lipoprotein levels [23,25,59,[64][65][66]. Indeed, several training studies in which subjects performed regular endurance exercise (two to five times per week), 30-60 min day-', at an intensity of about 50-70% of maximal heart rate or oxygen consumption) reported reductions in body weight [23, 25, 651, fasting plasma insulin levels [65], LDL-C concentrations [23, 59,[64][65][66] as well as significant increases in plasma HDL-C levels [23, 59, 651.…”

“…Indeed, several training studies in which subjects performed regular endurance exercise (two to five times per week), 30-60 min day-', at an intensity of about 50-70% of maximal heart rate or oxygen consumption) reported reductions in body weight [23, 25, 651, fasting plasma insulin levels [65], LDL-C concentrations [23, 59,[64][65][66] as well as significant increases in plasma HDL-C levels [23, 59, 651. Most of these studies have not observed any association between changes in and concomitant changes in lipoprotein levels [59,64,651 with the exception of two that reported significant associations between changes in and changes in plasma TG [66] and very-low-densitylipoprotein (VLDL) TG [66] levels, or in LPL activity [25]. Interestingly, the study by Stubbe et al [25], which compared the effects of high-intensity versus low-intensity exercise training, reported a negative Values are m e a n s f s m : * P < 0.05; * * P i 0.01; f P < 0.001; correlation between changes in plasma HDL-C levels and exercise intensity.…”

“…However, exercise training per se (in the absence of body weight reduction) has also been shown to induce significant and favourable changes in the metabolic profile that may reduce the risk of CHD. Indeed, favourable changes in the lipoprotein/lipid profile [59,64,66,811 and in insulin sensitivity [SO, 81, 971 have been observed in the absence of body weight or fat reduction. We have further investigated the role of concomitant loss of body fat on the metabolic improvements observed in 2-2 response to a 6-month endurance exercise training programme in a sample of 31 premenopausal obese women [81].…”

Exercise Training, Without Weight Loss, Increases Insulin Sensitivity and Postheparin Plasma Lipase Activity in Previously Sedentary Adults

“…Exercise training is known to decrease TG concentrations (9,10) and has been shown to increase the intravenous fat clearance (K 2 ) of a TG emulsion (11,12). Enhanced K 2 (92% greater clearance rate) has also been reported for endurance athletes, compared with sedentary men, in a cross-sectional study (13).…”

Relationship between Total Cholesterol and High-Density Lipoprotein Cholesterol and the Effects of Physical Exercise, Alcohol Consumption, Cigarette Smoking and Body Mass Index

“…walking) group (RMR<5). Since the elevated levels of HDLC have been reported in subjects who performed moderate exercise for at least 30min per day and 3 days per week (20)(21)(22)(23)(24)(25), the subjects who met these criteria were classified into the exercise group (28 men). The other 113 men who were practicing mild and/or moderate exercise infrequently (less than 3 days per week) or of short duration (less than 30min) were classified into the intermediate exercise group.…”