No abstract

Maximal dynamic exercise results in a postexercise hyperglycemia in healthy young subjects. We investigated the influence of maximal exercise on glucoregulation in non-insulin-dependent diabetic subjects (NIDDM). Seven NIDDM and seven healthy control males bicycled 7 min at 60% of their maximal O2 consumption (VO2max), 3 min at 100% VO2max, and 2 min at 110% VO2max. In both groups, glucose production (Ra) increased more with exercise than did glucose uptake (Rd) and, accordingly, plasma glucose increased. However, in NIDDM subjects the increase in Ra was hastened and Rd inhibited compared with controls, so the increase in glucose occurred earlier and was greater [147 +/- 21 to 169 +/- 19 (30 min postexercise) vs. 90 +/- 4 to 100 +/- 5 (SE) mg/dl (10 min postexercise), P less than 0.05]. Glucose levels remained elevated for greater than 60 min postexercise in both groups. Glucose clearance increased during exercise but decreased postexercise to or below (NIDDM, P less than 0.05) basal levels, despite increased insulin levels (P less than 0.05). Plasma epinephrine and glucagon responses to exercise were higher in NIDDM than in control subjects (P less than 0.05). By use of the insulin clamp technique at 40 microU.m-2.min-1 of insulin with plasma glucose maintained at basal levels, glucose disposal in NIDDM subjects, but not in controls, was enhanced 24 h after exercise. It is concluded that, because of exaggerated counter-regulatory hormonal responses, maximal dynamic exercise results in a 60-min period of postexercise hyperglycemia and hyperinsulinemia in NIDDM. However, this event is followed by a period of increased insulin effect on Rd that is present 24 h after exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Nutrient intakes from 7-d diet records were compared with hydrostatically determined body composition in 155 sedentary obese men aged 30-59 y. Percent body fats ranged from 18.6 to 40.3. The men ate (mean +/- SD) 2570 +/- 514 kcal/d: 15.6 +/- 2.6% from protein, 40.7 +/- 5.7% from fat, 37.5 +/- 6.9% from carbohydrate, and 6.2 +/- 6.0% from alcohol. Percent body fat correlated positively (p less than 0.05) with g/1000 kcal intake of total, saturated, and monounsaturated fatty acids and negatively with carbohydrates and plant protein. Total calories, number of meals, and distribution of calories were unrelated to percent body fat, total weight, or fat-free mass. The higher proportion of fat and carbohydrate in the diet may contribute to obesity in men. The modest caloric intake of these men and the lack of correlation between percent body fat and total calories suggest that calorie differences are not the major cause of the variations in obesity in these men.

We studied separately the influence of two methods for losing fat weight on the levels of plasma lipids and lipoproteins in overweight sedentary men--decreasing energy intake without increasing exercise (diet), and increasing energy expenditure without altering energy intake (exercise, primarily running)--in a one-year randomized controlled trial. As compared with controls (n = 42), dieters (n = 42) had significant loss of total body weight (-7.8 +/- 0.9 kg [mean +/- SE]), fat weight (-5.6 +/- 0.8 kg), and lean (non-fat) weight (-2.1 +/- 0.5 kg) (P less than 0.001 for each variable), and exercisers (n = 47) had significant loss of total body weight (-4.6 +/- 0.8 kg) and fat weight (-3.8 +/- 0.7 kg) (P less than 0.001 for both variables) but not lean weight (-0.7 +/- 0.4 kg). Fat-weight loss did not differ significantly between dieters and exercisers. All subjects were discouraged from altering their diet composition; however, dieters and exercisers had slight reductions in the percentage of kilojoules derived from fat. As compared with the control group, both weight-loss groups had significant increases (P less than 0.01) in plasma concentrations of high-density lipoprotein (HDL) cholesterol (diet vs. exercise, 0.13 +/- 0.03 vs. 0.12 +/- 0.03 mmol per liter), HDL2 cholesterol (0.07 +/- 0.02 vs. 0.07 +/- 0.02 mmol per liter), and HDL3 cholesterol (0.07 +/- 0.02 vs. 0.06 +/- 0.02 mmol per liter) and significant decreases (P less than 0.05) in triglyceride levels (diet vs. exercise, -0.35 +/- 0.14 vs. -0.24 +/- 0.12 mmol per liter). Levels of total and low-density lipoprotein cholesterol were not significantly changed, relative to values in controls. None of these changes were significantly different between dieters and exercisers. Thus, we conclude that fat loss through dieting or exercising produces comparable and favorable changes in plasma lipoprotein concentrations.

In major prospective studies it has been reported that high heart rate at rest predicts the development of coronary heart disease (CHD) or cardiovascular disease (CVD) in men, but the mechanisms producing these relationships are unknown. Since lipoprotein levels contribute strongly to the risk of CHD and CVD, we examined the relationship of resting heart rate to plasma concentrations of high-density (HDL), low-density (LDL), and very low-density (VLDL) SEVEN major prospective studies have found high heart rates in men at rest to be predictive of the future manifestation of coronary heart disease (CHD) or cardiovascular disease (CVD): (1)