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Vol. 5 nr.2 |
ANTHROPOLOGY AND PHYSICAL ACTIVITY: A LIFESPAN PERSPECTIVE
ROBERT M. MALINA
Department of Kinesiology, Michigan State University, East Lansing, MI, USA
ABSTRACT
The presently available evidence indicates significant, but generally moderate relationships between physical activity and health-related physical fitness in childhood and adolescence, and physical activity and health status in adulthood. This is not surprising given the variety of methods of estimating habitual physical activity and tests of health-related physical fitness. A major proportion of the variability in indicators of health-related and metabolic fitness is not accounted for by physical activity as assessed in the available studies. Nevertheless, the trends emphasize the importance of a lifestyle of regular physical activity during childhood and adolescence, which continues into and throughout adulthood, for the health and well-being of the individual and the population. The trends also emphasize the need for further study of the interactions among physical activity, physical fitness and health status in childhood, adolescence and adulthood.
Key words: activity, fitness, childhood, adolescence, adulthood, tracking
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SOME EVILS OF PROLONGED BED-REST DECONDITIONING
JOHN E. GREENLEAF
Laboratory for Human Environmental Physiology, NASA, Ames Research Center, Moffett Field, California, USA
ABSTRACT
The adaptive physiological and psychological responses in humans as a result of their decreased physical fitness (deconditioning) during prolonged bed rest are appropriate for that new hypogravic (reduced hydrostatic pressure) and hypodynamic (reduced energy utilization) state. In healthy people, however, this new adaptive state follows the tenet that use promotes function and disuse results in disfunction and atrophy. Virtually all body systems are affected by this hypoactive deconditioning, and four are discussed: insulin-glucose intolerance because of potential diabetic effects and as an indicator of more far-reaching changes in intermediary metabolism; muscular atrophy because it impedes reambulation and may be associated with the glucose intolerance; immune function because of its critical role, in conjunction with the neuroendocrine system, for physiological control; and psychological perturbations which influence behavior and, with the immune system, the healing process in hospitalized patients. It is probable that these deconditioning responses could interfere with accurate differential diagnoses in early and especially later stages of bed rest.
Key words: atrophy, hypogravia, hypodynamia, physical fitness
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MINERAL CONCENTRATIONS IN HUMAN SWEAT DURING XERCISE
Magdalena Przepiórka
Katedra Dietetyki i Żywności Funkcjonalnej
Wydział Nauk o Żywieniu Człowieka i Konsumpcji, SGGW, Warszawa, Poland
Abstract
Sweat losses during exercise in hot and humid environment may be as high as 10 l/d. The issue of mineral losses in sweat is important because of the risk of deficiency of some elements. The average values for mineral concentrations in human sweat, usually reported in the literature are: 20-80 mmol/l for sodium, 4-8 mmol/l for potassium, 0-1 mmol/l for calcium, 5-15 µmol/l for zinc, 1-10 µmol/l for iron, 2-10 µmol/l for copper and 0.3-1.5 mmol/l for magnesium. Several factors, which influence sweat composition are also discussed in this paper. A review of the literature on sweat composition indicates that significant amounts of sodium, potassium, calcium, zinc, and copper may be lost in sweat, especially under conditions of profuse sweating. These losses are particularly important for people on marginal and deficient diets, in spite of the conservation mechanisms observed for some elements (sodium, chloride, zinc). Acclimatization to exercise in the heat will result in lower excretion of sodium and chloride but other element concentrations will still be high. Sweat losses of these minerals should be included as part of the total daily output in balance studies and in the estimation of requirements. At present state of knowledge we cannot say that supplementation of any elements due to their dermal loss is necessary, but athletes training in hot and humid environments should be aware of this problem and should pay more attention to their diet.
Keywords: sweat composition, electrolytes, minerals, exercise, mineral balance
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A SINGLE DOSE OF VITAMIN C MAY NEGATIVELY AFFECT AEROBIC POWER IN SOME INDIVIDUALS
Rhonda D. Prisby1, Arnold G. Nelson2
1 Kent State University, School of Exercise, Leisure and Sport, Kent, OH, USA
2 Louisiana State University, Department of Kinesiology, Baton Rouge, LA, USA
ABSTRACT
Traditionally, the research effects of vitamin supplementation upon health and exercise performance have been a favorite topic. Recent investigations have shown that large doses of vitamin C may enhance endothelial responses. Therefore, vitamin C (as a vasodilator) may provide a possible ergogenic benefit by maintaining high blood flows to the heart and skeletal muscles. Unfortunately, previous investigations into the effect of vitamin C on exercise parameters have produced inconclusive results. In agreement with several previously published reports, this study demonstrated that vitamin C had no impact on maximal aerobic power (VO2max), and therefore, will not enhance aerobic performance. In fact, further analysis of the data revealed that such an ingestion prior to exercise might negatively impact some individuals.
Keywords: vitamins, supplementation, athletic performance, and ergogenic aid
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THE INFLUENCE OF REHABILITATION TRAINING ON SERUM CONCENTRATIONS OF LIPOPROTEIN(A) IN PATIENTS WITH ISCHEMIC HEART DISEASE
Stankiewicz Krystyna1, Szczęśniak Łucja1, Rychlewski Tadeusz1, Dylewicz Piotr2, Deskur Ewa2, Przywarska Izabela2, Bieńkowska Sławomira2
1 Department of Physiology, Biochemistry and Hygiene, University School of Physical Education, Poznań
2 Department of the Cardiac Rehabilitation, University School of Physical Education, Poznań
ABSTRACT
This study examined the effect of physical training at an intensity below ventilatory threshold on serum concentrations of lipoprotein(a) [Lp(a)] in patients with ischemic heart disease. Thirty four patients, after myocardial infarction, and 20 patients, after coronary artery bypass grafting, were admitted to a 3-week cardiac rehabilitation program. The program consisted of 15 sessions of continuous exercise, each in duration 40 min. Fifteen subjects with a history of myocardial infarction or coronary artery bypass grafting who did not participate in a rehabilitation program constituted the control group. Serum Lp(a) levels were measured by immunoenzymatic method (Cormay, Poland). Upon admission, 56% of patients after myocardial infarction and 55% of patients after coronary artery bypass grafting had elevated serum lipoprotein(a) levels. The applied physical training of low intensity and prolonged duration resulted in significant decrease in serum Lp(a) levels in both study groups. The reduction of Lp(a) concentrations was observed both in patients with considerable hyperlipoproteinemia(a) and in subjects with Lp(a) levels within the normal range. In the control group Lp(a) levels remained unchanged. The study findings indicate that continuous training based on aerobic exercise favorably alters atherogenic lipoprotein(a) levels and confirm the important role of physical activity in the prevention of ischemic heart disease.
Key words: lipoprotein(a), ischemic heart disease, physical exercise
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