Even low-intensity and low-volume exercise training may improve insulin resistance in the elderly.

OBJECTIVE: Moderate to high intensity exercise training is known to ameliorate the coronary risk factors in relation to an improvement in body composition. However, the benefit of low-intensity and low-volume training for these risk factors remains unclear in elderly people. Therefore, we investigated the effects of low-intensity and low-volume exercise training on blood lipid values and insulin resistance in the elderly. METHODS: A total of 56 healthy elderly individuals (42 females and 14 males) aged 64+/-6 years participated in a 12-week exercise program, comprising aerobic training and resistance training. RESULTS: After the program, there were no significant changes in high-density lipoprotein cholesterol, triglyceride serum levels, or in peak oxygen uptake on average. However, the homeostasis of minimal assessment of insulin resistance (HOMA-IR) value was significantly reduced by 21%. The participants were categorized into tertiles based on initial Body Mass Index (BMI). The Middle-BMI group (non-obese subjects) showed reduced HOMA-IR (2.0-->1.3, P<0.01), but this reduction was not associated with the reduction in BMI (r=0.08, P=0.74), whereas the two reductions were significantly associated in the High-BMI group (r=0.61, P=0.01). CONCLUSION: Even low-intensity and low-volume exercise training, which would ordinarily be insufficient for improving mean lipid values or aerobic fitness, was found to be effective in improving insulin resistance in the elderly. The improvement in insulin resistance was independent of the improvement in obesity.

Effect of aerobic exercise training on serum levels of high-density lipoprotein cholesterol: a meta-analysis.

BACKGROUND: Aerobic exercise is believed to reduce the risk of cardiovascular disease partially through increasing serum levels of high-density lipoprotein cholesterol (HDL-C). However, this effect varies considerably among exercise intervention studies. METHODS: Electronic database searches of MEDLINE (1966-2005) for randomized controlled trials that examined the effect of exercise training on HDL-C level. RESULTS: Twenty-five articles were included. Mean net change in HDL-C level was statistically significant but modest (2.53 mg/dL [0.065 mmol/L]; P<.001). Minimal weekly exercise volume for increasing HDL-C level was estimated to be 900 kcal of energy expenditure per week or 120 minutes of exercise per week. Univariate regression analysis indicated that every 10-minute prolongation of exercise per session was associated with an approximately 1.4-mg/dL (0.036-mmol/L) increase in HDL-C level. In contrast, there was no significant association between exercise frequency or intensity. Multiple meta-regression analyses demonstrated that subjects with a body mass index (calculated as weight in kilograms divided by height in meters squared) less than 28 and total cholesterol level of 220 mg/dL [5.7 mmol/L] or more experienced an approximately 2.1-mg/dL (0.054-mmol/L) larger increase in HDL-C level than those with a body mass index of 28 or more and total cholesterol level less than 220 mg/dL (5.7 mmol/L). CONCLUSIONS: Regular aerobic exercise modestly increases HDL-C level. There appears to exist a minimum exercise volume for a significant increase in HDL-C level. Exercise duration per session was the most important element of an exercise prescription. Exercise was more effective in subjects with initially high total cholesterol levels or low body mass index.