William W. Heusner

Exercise training and severe caloric restriction: Effect on lean body mass in the obese

The purpose of this study was to investigate the effects of exercise intensity on the body composition of obese subjects during severe caloric restriction. Forty obese subjects (33 women, 7 men; 41 +/- 7.7 years; 106 +/- 26kg; body fat > 25% men, > 30% women) on a commercially prepared OPTIFAST 420kcal/day supplemented fast were randomized into groups that exercised at target heart rates corresponding to 40% and 60% of the heart rate reserve (HRR) at the start of the program. Training volume was similar for both groups at approximately 300kcal per session three times per week for 12 weeks. Body weight, body fat, and lean weight were similar for both exercise intensity groups at week one. Overall, body weight decreased by 15.3 +/- 6.7 kg (p < or = .05), and body fat decreased by 14.9 +/- 5.0 kg (p < or = .05) for the 40 subjects, whereas lean weight remained unchanged. No significant differences in body weight, body fat, or lean weight were observed between the two groups. The results of the current study indicated that while on a supplemented 420-kcal/day fast, exercise at 40% and 60% of the HRR affected body composition similarly when total training volume was held constant at 900kcal/week. Lean weight remained unchanged and accompanied a 14.9 +/- 5.0-kg decrease in body fat, which may have resulted when the volume of exercise (ie, 900kcals/wk) was factored into the exercise prescriptions. These results suggest that exercising at 60% of the HRR offers no advantages for body composition changes over those obtained from exercising at 40% of HRR when the total volume of exercise training is controlled.

Effects of an anabolic steroid and sprint training on selected histochemical and morphological observations in rat skeletal muscle types

SummaryThe effects on selected histochemical and morphological parameters of anabolic steroid administration and of high-intensity sprint running, separately, and in combination, were studied in young adult male rats. Dianabol (methandrostenolone) 1 mg/day for 8 weeks had no significant effects on phosphorylase or glycogen staining intensities and on fiber area in skeletal muscles of either trained or sedentary animals. The program of sprint training resulted in significantly decreased intensities of phosphorylase in all ten regions of the gastrocnemius, plantaris, and soleus muscles that were studied. Glycogen localization was significantly increased with training in five regions of the gastrocnemius and plantaris muscles which contained predominantly fast-twitch fibers. No changes in fiber area occurred with the training program. We conclude from these results that (a) normal androgen levels in young, healthy male animals are sufficiently high so that the intake of large doses of anabolic steroid does not result in the stimulation of glycogen metabolism or hypertrophy of skeletal muscle; (b) the changes induced by high-intensity, short-duration sprint training suggest that the existing glycolytic capacity of muscle is adequate to supply the muscles energy needs even during the stress of very strenuous exercise, and that more fast-twitch fibers were recruited by the exercise regimen than slow-twitch fibers.

A Comparison of Knowledges, Attitudes, and Behaviors before and after Major Revisions in a University Health Promotion Course

Abstract The effects of a university health-promotion course were evaluated before and after major course revision. Knowledges, attitudes, and behaviors were assessed at the beginning and end of the class for all students taking the original course during 1987–88 (n=195) and the revised course during 1988–89 (n=250). The content areas addressed were exercise, nutrition, substance abuse, stress management, safety, cancer, and cardiovascular disease (CVD). Course revisions involved altering content emphases, adding a series of quizzes, expanding the assigned readings, incorporating nutrition and substance abuse self-evaluations, and providing detailed lecture outlines for students and instructors. Within-group analyses showed that both courses produced significant (P<.05) improvements in various knowledges and attitudes, whereas fewer behavioral modifications were realized. Between-group comparisons revealed that the revised course yielded enhanced benefits in terms of increased knowledges in the areas of s...

Moderate exercise in young female S5B/P1 rats does not reduce body fat.

Weanling S5B/P1 female rats were divided into four groups as follows: high fat diet, exercised (FE); high fat diet, unexercised (FU); high carbohydrate diet, exercised (CE); and high carbohydrate diet, unexercised (CU). After 25 days of progressive training, exercised rats ran on a motor-driven treadmill for 30 days at 25 m/min per 1 h at 0 degree grade for 6 days a week. Rats were weighed weekly throughout the experiment and food intakes were recorded for the last 3 weeks of the experiment. After euthanasia at 15 weeks of age, three muscles, liver, heart, kidney, 3 fat depots, and tibia-fibula were dissected out and weighted. The carcass, including weighted organs and fat depots, was analyzed for body fat. Exercised rats, regardless of diet, weighed slightly but significantly more than unexercised rats. They also tended to eat more food and to have a higher quantity of fat-free body mass than unexercised rats. Percent body fat was similar for exercised and unexercised rats. The tibia weighed significantly more (p less than 0.05) in CU than in FU rats but the weight was similar in CE and FE rats. The density of the tibia was significantly higher (p less than 0.01) in exercised than in unexercised rats.

Effects of swimming on dystrophic Syrian hamster heart.

Morphological and histopathological heart changes were determined for sixteen dystrophic Syrian hamsters (B10 14.6 strain) and sixteen normal hamsters. Eight animals were randomly assigned to each of the following groups: dystrophic swim (DYS-SWM), dystrophic sedentary (DSY-SED), normal swim (NOR-SWM), and normal sedentary (NOR-SED). The daily swimming program consisted of an initial 30-minute swim which was gradually extended to 60 minutes by the end of eight weeks. Weights up to 3% body weight were attached during swimming to increase the work load. Sedentary animals received no experimental treatment. Four animals in each group were sacrificed at 4 and 8 weeks after the initiation of treatments. In comparison with the two groups of sedentary animals, the NOR-SWM group had a greater heart weight/body weight ratio at both 4 and 8 weeks (P less than .05), while the DYS-SWM group had an increased ratio only at 8 weeks (P less than .05). Subjective histopathological evaluation of heart lesions showed that the DYS-SED group had many large areas of inflammatory reaction with infrequent diffuse areas of calcification. In contrast, the DYS-SWM group had fewer and smaller areas of inflammatory reaction with moderate amounts of calcification.

Histochemical and morphological observations on rat myocardium after exercise.

Effects of seven levels of chronic physical activity on the metabolic and morphologic characteristics of left ventricular myocardium of adult male albino rats were investigated.Treatments included sedentary control; voluntary running; short-duration, high-intensity running; medium-duration, moderate-intensity running; long-duration, low-intensity running; electric stimulus control; and endurance swimming. Excluding the controls, the animals were trained 5 days per week for 8 consecutive weeks. Food and water were providedad libitum to them. Fifty-six animals comprised the final sample.Histochemical techniques were used to evaluate the relative glycogen, fatty acid, SDH and LDH concentrations in the cardiac fibers. Each stain was measured objectively, using a photometer. A Hematoxylin and Eosin stain was employed to rate morphologic features. These sections were evaluated subjectively on the basis of presence or absence of lesions.Physical training for 8 weeks was sufficient to produce metabolic adaptations in the rats. The trained animals gained 37.4 % less body weight than did the sedentary controls (P < 0.05). However, neither histochemical nor morphological changes had occurred to the hearts of these animals consequent to the 8 weeks training programs. Apparently, the myocardial tissues examined, from the trained animals, contain the enzymes, SDH and LDH, and the substrates, glycogen and fatty acids, in amounts greater than that needed to cope with the exercise stress afforded by these training programs.

Effects of Prepubertal Forced Exercise Upon Postpubertal Organ and Body Weights of Female Rats.

Abstract One-hundred-fifty female rats were used in this study of the immediate and residual effects of prepubertal exercise upon organ and body weights. Animals were randomly assigned to 3 initial treatment groups: sedentary (S), voluntary (V), and voluntary plus forced exercise (V+F). Forced exercise consisted of 35 daily 30-min. swims with a tail weight of 2% of body weight. Two treatment periods were given, one just before puberty and another after 165 days of intervening voluntary activity. Sacrifices occurred posttreatment I, pretreatment II, and posttreatment II. Both (V) and (V+F) animals had lower body and absolute spleen weights but higher relative adrenal, heart, and liver weights than the controls. The absolute spleen and relative adrenal differences remained pretreatment II. Posttreatment II, lower body and absolute spleen weights were noted in (V) than in (S) groups. Although several significant interactions between treatments I and II were observed, only the lower body weight of active anim...

Separate and simultaneous effects of aerobic exercise and anxiety on myocardial damage in the rat

The purpose of this study was to determine the effects of various programs of physical activity on anxiety-related myocardial damage in rats. The anxiety-producing stress consisted of randomly distributed applications of a disturbing but nonpainful electrical shock. Physical activity consisted of long-duration, low-speed running. Three hundred and seventy-five male albino rats were randomly assigned to five comparison groups. The results show that the anxiety treatment produced marked myocardial damage. Animals preconditioned by eight weeks of exercise prior to the introduction of the anxiety treatment did not suffer as much myocardial damage as did animals that were not preconditioned. However, a group in which exercise and anxiety were introduced simultaneously had the highest incidence of myocardial necrosis. We conclude that aerobic exercise can modify the effects of a subsequent or simultaneous anxiety-producing stressful situation on the myocardium of the laboratory rat. The time at which the exercise is imposed determined the nature of the effect.

Reversal of the energy metabolism responses to endurance training by weight loading.

6 university team distance runners were randomly placed into experimental and control groups to determine the effect of progressive overloading with weights upon selected training responses. Both groups received identical training for 8 wk. with the exception that three days each week the experimental Ss wore weighted wristlets, anklets, and belts. Pre- and posttest energy metabolism measures were taken during and following both a low-intensity 15-min. run (9.7 km/hr, 0% grade) and a high-intensity run to exhaustion (16.1 km/hr, 9% grade). The energy metabolism responses to endurance training were significantly reversed by the progressive overloading with weights. The energy cost of the low-intensity run was increased and an unexpected shift toward greater anaerobic metabolism was observed.