摘要:

The mechanisms governing the body’s response to physical exercise have been investigated from various perspectives including metabolism, nutrition, age and sex. Increased attention to the immune system during recent decades is reflected by a rapidly growing number of publications in the field. This article highlights the most recent findings and only briefly summarises more basic concepts already reviewed by others. Topics include Th1/Th2 cytokine balance, inoculation time, age and immune compensation. Some less investigated areas are discussed including studies in children, the environment and dendritic cells.Because physical exercise enhances some aspects and suppresses other aspects of immunity, the biological significance of alterations in the immune system are unknown. So far, no link between immunological alterations and infection rate has been established and infection after strenuous physical exercise is equally likely to be the result of exercising with an already established rather than a new infection. If there is an increased risk for infections with increased exercise duration and intensity, why do overtrained athletes not display the greatest risk for upper respiratory tract infections? Increased knowledge on immune system modulations with physical exercise is relevant both from a public health and elite athlete’s point of view.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

Respiratory exercise physiology research has historically focused on male subjects. In the last 20 years, important physiological and functional differences have been noted between the male and female response to dynamic exercise where sex differences have been reported for most of the major determinants of exercise capacity. Female participation in competitive and recreational sport is growing worldwide and it is universally accepted that participation in regular physical activity is of health benefit for both sexes. Understanding sex differences is of potential importance to both the clinician-scientist and the exercise physiologist since differences could impact upon exercise rehabilitation programmes for patient populations, exercise prescription for disease prevention in healthy individuals and training strategies for competitive athletes. Sex differences have been shown in resting pulmonary function, which may impact on the respiratory response to exercise. Women typically have smaller lung volumes and maximal expiratory flow rates even when corrected for height relative to men. Differences in resting and exercising ventilation across the menstrual cycle and relative to men have also been reported, although the functional significance remains unclear. Expiratory flow limitation and a high work of breathing are seen in women. Pulmonary system limitations, in particular exercise-induced arterial hypoxia, have been reported in both men and women; however, the prevalence in women is not yet known. From the available literature, it appears that there are sex differences in some areas of respiratory exercise physiology. However, detailed sex comparisons are difficult because the number of subjects studied to date has been woefully small.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

Numerous physical activity and physical fitness recommendations exist for youth. To date, however, no investigator has systematically reviewed these public health and clinical guidelines to determine whether the recommendations address overweight youth. This review examines youth-oriented physical activity and physical fitness recommendations for both the public health community and the clinical community, and assesses how overweight youth are specifically targeted by each of these two groups. Our review determined the extent to which the recommendations assessed four components of physical activity (i.e. frequency, intensity, duration and type) and four components of physical fitness (i.e. cardiorespiratory capacity, strength, flexibility and body composition). We further reviewed clinical recommendations to determine how they included two facets of the physician-patient encounter: assessment and counselling. After identifying all current physical activity and physical fitness recommendations for youth, we evaluated whether public health (n = 13) and clinical recommendations (n = 12) addressed physical activity and physical fitness for overweight youth. Findings revealed inconsistent, yet explicit, recommendations for the public health community where most organisations (12 of 13, 92%) included ≥3 physical activity components. In addition, organisations encouraged volumes of daily moderate- to vigorous-intensity physical activity for youth ranging from 30–60 or more minutes. Recommendations for the clinical community generally did not provide explicit physical activity and fitness recommendations to advise physicians on the assessment and counselling of patients and their families. Overweight youth were addressed within some recommendations (6 of 12, 50%) for the clinical community, but within few recommendations (2 of 13, 15%) for the public health community. To best inform public health and clinical communities, organisations developing future recommendations should include information fully documenting the decision-making processes used to develop the recommendations. In cases where mutual goals exist, public health and clinical communities should consider collaborating across agencies to develop joint recommendations.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

In premenopausal women, the most severe menstrual dysfunction is amenorrhoea, which is associated with chronic hypoestrogenism. In postmenopausal women, hypoestrogenism is associated with a number of clinical sequelae related to cardiovascular health. A cardioprotective effect of endogenous oestrogen is widely supported, yet recent studies demonstrate a deleterious effect of hormone replacement therapy for cardiovascular health. What remain less clear are the implications of persistently low oestrogen levels in much younger amenorrhoeic athletes. The incidence of amenorrhoea among athletes is much greater than that observed among sedentary women. Recent data in amenorrhoeic athletes demonstrate impaired endothelial function, elevated low- and high-density lipoprotein levels, reduced circulating nitrates and nitrites, and increased susceptibility to lipid peroxidation. Predictive serum markers of cardiovascular health, such as homocysteine and C-reactive protein, have not yet been assessed in amenorrhoeic athletes, but are reportedly elevated in postmenopausal women. The independent and combined effects of chronic hypoestrogenism and exercise, together with subclinical dietary behaviours typically observed in amenorrhoeic athletes, warrants closer examination. Although no longitudinal studies exist, the altered vascular health outcomes reported in amenorrhoeic athletes are suggestive of increased risk for premature cardiovascular disease. Future research should focus on the presentation and progression of these adverse cardiovascular parameters in physically active women and athletes with hypoestrogenism to determine their effects on long-term health.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS