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PubMed1990

Physical fitness in relation to amount of physical exercise, body image, and locus of control among college men and women.

The relations of amount of exercise, body image, and locus of control to physical fitness were investigated. The Hall Physical Fitness Test Profile, the Winstead and Cash Body Self-relations Questionnaire, and the Nowicki-Strickland Locus of Control Scale were administered to 243 freshmen. Students estimated the amount of time spent exercising on a 9-point scale ranging from no regular exercise to 10 or more hours per week for the preceding three months. Exercise included brisk walking, jogging, aerobics, and sports activities like soccer, tennis, and swimming. Increased fitness was associated with increased amounts of exercise, internal locus of control, and good body image. There was a statistically significant interaction between sex and amount of exercise. For students who exercised 2-4.9 hours per week, men were more fit than women. Fitness was comparable for men and women exercising less than two hours or at least five hours per week. Women had to exercise 5 or more hours weekly to achieve the fitness level of men who exercised 2 to 4.9 hours per week.

Adolescent↗
PubMed1996

Pivalic acid-induced carnitine deficiency and physical exercise in humans.

To study the effect of carnitine depletion on physical working capacity, healthy subjects were administered pivaloyl-conjugated antibiotics for 54 days. The mean carnitine concentration in serum decreased from 35.0 to 3.5 mmicromol/L, and in muscle from 10 to 4.3 micromol/g noncollagen protein (NCP). Exercise tests were performed before and after 54 days' administration of the drug. At submaximal exercise, there was a slight increase in the concentration of 3-hydroxybutyrate in serum, presumably caused by decreased fatty acid oxidation in the liver. There was also a decreased consumption of muscle glycogen, indicating decreased glycolysis in the skeletal muscle. The muscle presumably had enough energy available, since there was no significant decrease in the concentration of adenosine triphosphate (ATP) and creatine phosphate during exercise. The work at maximal oxygen uptake (VO2max) and the maximal heart rate were reduced. Since VO2max is considered dependent on heart function, carnitine depletion seemed to affect cardiac function.

Adolescent↗
PubMed1991

Caffeine and sport: role of physical exercise upon elimination.

Urinary excretion of caffeine in two populations (men and women) of cyclotourists was measured, at rest and during exercise, after oral administration of 350 mg of caffeine in aqueous solution. The so-called "total metabolites", as measured by the EMIT test, were also determined, as well as urinary creatinine. At rest, elimination in relation to body weight was identical in men and women. During exercise a fivefold decrease in the female and twofold decrease in the male populations were observed. After exercise, caffeine elimination was greater than during the physical trial but remained lower for women than for men. "Total metabolites" excretion showed evidence for a slowing of caffeine catabolism during exercise and a restart of it after exercise. The caffeine content of beverages varies considerably from one country to another, depending on local customs, so that caffeine intake may be highly variable. Our results lead us to query the validity of the upper authorized official limit for urinary caffeine (12 micrograms.ml-1) in doping controls. The nature of the sporting event, sex, weight, and sampling delay after exercise are all factors that argue against the utilization of a unique standard.

Adult↗
PubMed1995

Physical exercise and reduced risk of nonfatal myocardial infarction.

While the inverse association between physical activity and coronary heart disease risk is well documented, questions remain regarding the intensity of exercise, the potential for confounding by other risk factors for coronary heart disease, and the role of blood lipids and apolipoproteins. The authors examined these issues in the Boston Area Health Study, a case-control study of 340 patients (266 men, 74 women) who survived a first myocardial infarction between January 1, 1982, and December 31, 1983, and 340 controls matched on sex, age, and residence. The relative risk of myocardial infarction for those in the highest quartile of physical activity, compared with the lowest, was 0.50 (95 percent confidence interval (CI) 0.31-0.80) for men and 1.00 (95 percent CI 0.41-2.43) for women. When subjects were categorized by level of energy expenditure on moderate to vigorous sports alone, men in the most active category had 0.39 (95 percent CI 0.23-0.69) times the risk of those in the least active category, and women, 0.43 (95 percent CI 0.15-1.26) times the risk. Adjustment for body mass index, smoking, alcohol intake, diet, personal and family medical history, and personality type did not substantially change results nor did further adjustment for blood lipids. This was not surprising as total energy expenditure was uncorrelated with blood lipids or apolipoproteins. Moderate to vigorous sporting activity, however, appeared to be directly related to high density lipoprotein (HDL) cholesterol (p = 0.06), especially the HDL2 subfraction (p = 0.10). In these data, findings suggest that physical activity is inversely related to myocardial infarction risk, independently of other risk factors for coronary heart disease.

Adult↗
PubMed1995

Behaviour of zinc in physical exercise: a special reference to immunity and fatigue.

The variations in plasma zinc levels is dependent which follows intensivity of exercise. It is clear that there are short-term effects of exercise on zinc metabolism. It has also been shown that a high level of constant exercise can have long-term effects on zinc metabolism. It has been reported that runners have lower plasma zinc levels than controls. Long term endurance training has been shown to significantly decrease resting serum zinc levels in both male and female athletes compared to sedentary controls. Severe zinc deficiency can affect muscle function. One consequence of low serum zinc levels could be a reduction in muscle zinc concentrations. Since zinc is required for the activity of several enzymes in energy metabolism it could be predicted that low muscle zinc levels would result in a reduction in endurance capacity. Zinc may also be acting directly at membrane level; changes in extracellular zinc levels have been reported to influence twitch-tension relationship in muscle. Some investigators have associated acute and exhaustive exercise with decreased immune function. The mechanisms by which physical stress modulates immune competence are complex, involving both immune and neuroendocrine messengers. Muscular fatigue is of critical importance and as such it has been the subject matter of numerous investigators. Although many factors have been identified, a clear cause remains elusive. Factors discussed include: energy supply, the accumulation of metabolites, eccentric work, immune dysfunctions, etc. Recently we have demonstrated that daily high and maintained physical training over a prolonged period of time (7 mo) provokes marked modifications in the immune system of elite sportsmen accompanied by a psychological and biochemical stress level.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2006

[Attentional control of postural stability in institutionalised elderly people: effects of a physical exercise program].

OBJECTIVE: We aimed to examine the effect of a physical activity program on postural sway and on the attentional control of postural abilities in elderly frail adults. METHOD: Twelve older adults (age 81.4+/-9 years) institutionalised in a geriatric care institution participated in the physical activity program posture-balance-mobility (PBM) twice a week (1 hour per session) for 12 weeks. We analysed stabilometric data for surface and length of the center of pressure (COP) sway, with eyes open and eyes closed, under single-task and dual-task conditions on a firm floor before and after the training program. During the static postural evaluation and under the dual-task condition, subjects performed an attention-demanding cognitive task, the random number generation task. RESULTS: Only the length of COP sway was more important under the dual-task condition than under the single-task condition (p=0.05). At baseline, cognitive performance was significantly weaker under the dual-task condition (standing) than under the single-task condition (seated), with eyes closed but not eyes open (p<0.05). However, after the training program, the performance of the cognitive task did not significantly differ between the dual-task condition with eyes closed and the single-task condition with eyes closed. CONCLUSION: The training program allowed elderly subjects to improve their ability to perform an attention-demanding cognitive task while standing still, in particular with their eyes closed. Although balance seemed to be less stable under the dual-task condition than under the single-task condition, these results could be interpreted as an improvement of the attentional control of postural stability.

Aged, 80 and over↗
PubMed2001

[Amount and intensity of physical exercise in primary prevention].

Numerous epidemiological studies have demonstrated an inverse relation between physical activity and physical "fitness" on one hand and premature death and the risk of chronic disease on the other hand. However, most of these studies showed crucial methodological and statistical differences, a fact which caused a lack of consensus of dose and intensity of physical activities for "health benefits". The optimal amount of physical activity to decrease mortality is in literature stated to range between 1,000 and 3,500 motoric kcal per week. Only a few data exist concerning the optimal intensity of preventive physical activities. There is some indication that only "vigorous" but not "non-vigorous" physical activities are associated with decreased mortality. Previous investigations suggest that a "threshold-intensity" (e.g. of at least 6 MET of "conditioning physical activity") is needed to produce an adequate preventive effect. On the other hand it has been documented, that "physical fitness" (endurance capacity) is a decisive factor for a decreased mortality. Therefore it may be assumed, that physical activities are only efficient for health benefits, if they also result in increased physical fitness. Following from this assumption the quality and quantity of training in primary prevention has to be adjusted to the individual requirements (performance, age, gender, health) of men.

Age Factors↗
PubMed1981

[Metabolic and hormonal response to physical exercise under acute beta 1-adrenergic blockade (author's transl)].

In 14 healthy physical education students the effect of acute beta 1-adrenergic blockade (100 mg metoprolol) on maximal and prolonged exercise capacity, carbohydrate and lipid metabolism, catecholamines, insulin, growth hormone, and cortisol was studied in a double-blind trial. Metoprolol had no effect on maximal oxygen uptake. The 3.5% reduction of maximal exercise capacity had to be attributed to the reduced maximal lactate concentration. Maximal heart rate was reduced by approximately 22%. At submaximal work loads (treadmill) exercise with gradually increasing velocity), lipolysis appeared to be inhibited, arterial glucose and lactate concentrations were unaffected. With metoprolol, epinephrine levels at rest and submaximal work loads were elevated; no effect was apparent at maximal loads. Norepinephrine, insulin, growth hormone, and cortisol were unaffected in exercise with increasing work loads. In prolonged exercise at a constant load of approximately 70% of maximal exercise capacity, mean heart rate was reduced by 26%. Arterial lactate and glucose levels were essentially unchanged, free fatty acids and glycerol decreased by 50 and 30% respectively. With metoprolol, epinephrine increased by 100%, norepinephrine by 50% growth hormone by 60%, and cortisol by 90%, insulin remained unchanged. The results indicate that a reduction of exercise capacity by beta 1-adrenergic blockade in patients undergoing an endurance type training for therapeutic or rehabilitative purposes is unlikely to occur. The inhibition of lipolysis under metoprolol appears to be counteracted by the increased carbohydrate utilisation and by the increased secretion of the regulating hormones.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

[Physical exercise and the quantitative characteristics of moisture- excreting function of the lungs].

Physical loading has been used as a test to study the regulation of moisture excretion in the act of breathing in 101 healthy students, 62 men with external risk factors, and in 73 patients with respiratory diseases (chronic bronchitis, acute pneumonia, bronchial asthma). The correlation of moisture excretion with the parameters of ventilation, age, sex, body weight of examinees proved that physical loading in the age-groups above 50 with excess body weight and with hyperventilation resulted in blocking effect on the volume of moisture loss during breathing. Thus, these endogenic factors determine the individual reaction in dynamics of moisture loss during physical loading and could be considered as risk factors in deteriorations of moisture excreting function of lungs.

Adult↗
PubMed1988

Physical exercise and sleep: the effect of the age and sex of the subjects and type of exercise.

Exercise has generally been held to result in an increase in slow wave sleep (SWS) and sleep duration. We report the results of three experiments which assessed the effects of exercise on the sleep of young fit women as compared to young fit men; fit older men (aged 41 years) as compared to fit younger men (aged 22 years); and the effects of power exercise on the sleep of a group of trained power lifters. In each experiment physically fit subjects had their sleep assessed following both late afternoon exercise and no exercise conditions. In none of the experiments did exercise result in an increase in SWS or sleep duration. Instead the tendency was for exercise to affect sleep adversely.

Adult↗