No abstract

Current body mass index (BMI) norms for children and adolescents are developed from a reference population that includes obese and slim subjects. The validity of these norms is influenced by the observed secular increase in body weight and BMI. We hypothesized that the performance of children in health-related physical fitness tests would be negatively related to increased BMIs, and therefore fitness tests might be used as criteria for developing a more appropriate set of BMI norms. We evaluated the existing data from a nation-wide fitness survey for students in Taiwan (444 652 boys and 433 555 girls) to examine the relationship between BMI and fitness tests. The fitness tests used included: an 800/1600-m run/walk; a standing long jump; bent-leg curl-ups; and a sit-and-reach test. The BMI percentiles developed from the subgroup whose test scores were better than the 'poor' quartile in all four tests were compared with those of the whole population and linked to the adult criteria for overweight and obesity. The BMIs were significantly related to the results of fitness testing. A total of 43% of students had scores better than the poorest quartile in all of their tests. The upper BMI percentile curves of this fitter subgroup were lower than those of the total population. The 85th and 95th BMI percentile values of the fitter 18-year-old-students (23.7 and 25.5 kg m(-2) for boys; 22.6 and 24.6 kg m(-2) for girls) linked well with the adult cut-off points of 23 and 25 kg m(-2), which have been recommended as the Asian criteria for adult overweight and obesity. Hence, the BMI norms for children and adolescents could be created from selected subgroups that have better physical fitness. We expect that the new norms based on this approach will be used not only to assess the current status of obesity or overweight, but also to encourage activity and exercise.

A periodized endurance training is able to adapt physical and psychological needs and increase exercise performance. Dendritic cells (DCs) play a key role in regulation of the immune response. In the present study, we trained Sprague-Dawley (SD) rats for five weeks using a progressive endurance protocol with the aim of measuring the effect on myeloid DC differentiation and maturation. Rats were divided into a non-exercise group (NEG) and an exercise group (EG). Bone marrow cells were isolated from these rats after training and cultured in the presence of granulocyte/monocyte-colony stimulatory factor (GM-CSF) and interleukin (IL)-4, and the resultant immature DCs were triggered with lipopolysaccharide to mature. DCs were collected and the main characteristics of DCs were assessed. The recovery rate and the expression of major histocompatibility complex (MHC) class II molecules for DC collected from EG was markedly greater than NEG. The function of DCs from EG to trigger a mixed leukocyte reaction and IL-12 production was higher than NEG. There was no liver and renal toxicity observed in all rats. Changes in food/water consumption and body weight increase between the groups were normal for the conditions. This study demonstrated that periodized endurance training is able to modulate DC development and shift them towards a more mature state.

Hyperthermal stress and resulting free radical generation is known to impair endurance capacity and immune cell redistribution during prolonged exercise. Caffeic acid phenethyl ester (CAPE), a phenolic compound purified from propolis, has many biological and pharmacological activities including antioxidation. To examine whether CAPE has protective effect against hyperthermal stress in athletes, we isolated peripheral blood mononuclear cells (MNC) from competitive cyclists and assessed their response to hyperthermia with or without CAPE pretreatment. We found that pretreatment of cyclists' MNC with CAPE (0, 1, 2, 4 microg/mL) reversed or reduced hyperthermia-induced survival inhibition, necrosis, superoxide production, glutathione depletion, and intracellular superoxide burst in a dose-dependent manner. These results suggest that CAPE may enhance the hyperthermal tolerance in immune mononuclear cells of competitive cyclists.

Dendritic cells, the most potent antigen-presenting cells linking innate and adoptive immunity, are thought to be important targets of immune modulators such as exercise. We examined the effect of Tai Chi Chuan (TCC) on dendritic cells. TCC practitioners were further divided to high-level practitioners (TCC-H) and low-level practitioners (TCC-L). The quantities of myeloid and plasmacytoid dendritic cells were estimated by flow cytometry. We examined parameters including age, body weight, body length, body fat, and serum albumin level, in the controls, TCC-H and TCC-L, which did not differ significantly. The mean peak VO(2) (volume of O(2) utilization) of the TCC-H group was greater than that of the sedentary control group. White blood cell (WBC) count in the entire TCC group was greater than that of the controls. The quantity of myeloid dendritic cells was significantly greater in the TCC group, whereas the quantity of plasmacytoid dendritic cells was similar for both groups. Among the TCC subgroups, the quantity of myeloid dendritic cells, but not plasmacytoid dendritic cells, in the TCC-H group was greater than that of TCC-L practitioners. TCC could increase the number of circulating myeloid dendritic cells, but not plasmacytoid dendritic cells, in a performance level-dependent manner.