Search

The purpose of this study was to determine the effect of exercise intensity on lipoprotein responses. Eleven normolipidemic male volunteers (X +/- SD = 23.1 +/- 2.4) participated in the study. The subjects were assessed for VO2max and ventilatory threshold (VT), matched for VO2max and then randomly assigned to one of two groups: Group A, which exercised for 12 minutes at an intensity 15% below VT (n = 5), and Group B, which exercised for 12 minutes at an intensity 15% above VT (n = 6). The lipoprotein measures HDL-C, LDL-C, total cholesterol (TC), and triglycerides (TG) were assessed from blood samples taken pre-exercise and immediately post-exercise as well as one, 24, and 48 hours post-exercise. A 2 X 5 split plot ANCOVA (controlling for pre-exercise values), revealed no significant differences between groups for HDL-C, TC or LDL-C. However, when means were collapsed across groups, TC levels measured immediately post-exercise were significantly higher than those taken 24 and 48 hours post-exercise (168.0, 159.1, and 159.9 mg.dl-1, respectively; p less than 0.05). A significant interaction was found for the TG measurements. For Group A, TG levels were elevated immediately post-exercise, but decreased significantly at the 1 and 24 hours post-exercise sampling, before returning to baseline levels at the 48 hour post-exercise measurement (93.2 +/- 3.1, 69.5 +/- 4.2, 66.8 +/- 6.7 and 99.5 +/- 2.1 mg.dl-1, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluations of 55 pre-adolescent males were made to determine if differences existed in the serum levels of total triglycerides, total cholesterol, HDL-cholesterol, or HDL-cholesterol/total cholesterol ratios between groups with contrasting levels of body fatness and physical activity habits. Underwater weighing revealed a median body fatness of 13.8% and 5-d physical activity records revealed a median of 3.9 h for daily participation in moderate to very high intensity activities. These values were respectively employed to stratify the sample into groups characterized as "lower fatness" or "higher fatness," as well as "lower active" or "higher active." Statistical comparisons between these groups indicated an absence of body fatness effects on any of the serum lipids. However, in contrast to similarities in physical characteristics, body composition, and nutritional intake (except total calories) between the "lower active" and "higher active" groups, physical activity effects were noted for two of the four serum lipid traits. Greater exposure to activities classified as moderate to very highly intense was consistent with lower total triglycerides (52.1 mg/dl vs 68.2 mg/dl) and higher HDL-cholesterol/total cholesterol ratios (0.33 vs 0.29) in these 8- to 11-year-old males.

The effect of high intensity physical training (HIPT), conducted in an unsupervised (group A) or supervised (group B) setting, was studied in 23 middle-aged men with Type IV hyperlipoproteinemia (HLP). Following 10 weeks of HIPT intervention, significant metabolic changes were observed such as reductions in both fasting triglyceride and insulin levels, but no changes in fasting serum cholesterol or glucagon levels were found. Other favorable results noted included a significant improvement in physical fitness, as measured by increases in aerobic power, and a decrease in body fatness with only minimal weight losses. There were no significant differences in the results when groups A and B were compared. It was concluded that HIPT is an effective means of lowering fasting triglyceride and insulin levels in Type IV HLP individuals. In addition, such physical training programs can be conducted in either an unsupervised or supervised setting, provided the subjects are highly motivated.