Effects of aerobic exercise training on estrogen metabolism in premenopausal women: a randomized controlled trial.

BACKGROUND: Regular physical activity may alter estrogen metabolism, a proposed biomarker of breast cancer risk, by shifting metabolism to favor production of 2-hydroxyestrone (2-OHE1). Few studies, however, have examined this question using a randomized controlled trial. PURPOSE: To examine the effects of 12 weeks of aerobic exercise training on 2-OHE1 and 16alpha-hydroxyestrone (16alpha-OHE1) in premenopausal women. METHODS: Participants were healthy, regularly menstruating, Caucasian women, 20 to 35 years, body mass index of 18 to 29.9, not using pharmacologic contraceptives, with average or below average fitness [maximal oxygen consumption (VO(2max)), <40 mL/kg/min]. Following a baseline menstrual cycle, participants (N = 32) were randomly assigned to a 12-week aerobic exercise training intervention (n = 17) or usual lifestyle (n = 15). Height, body mass, body composition by dual-energy X-ray absorptiometry, and VO(2max) were measured at baseline and following the intervention. Urine samples were collected in the luteal phase of four consecutive menstrual cycles. RESULTS: The exercise group increased VO(2max) by 14% and had significant, although modest, improvements in fat and lean body mass. No significant between-group differences were observed, however, for the changes in 2-OHE1 (P = 0.944), 16alpha-OHE1 (P = 0.411), or the ratio of 2-OHE1 to 16alpha-OHE1 (P = 0.317). At baseline, there was an inverse association between body fat and 2-OHE1 to 16alpha-OHE1 ratio (r = -0.40; P = 0.044); however, it was the change in lean body mass over the intervention that was positively associated with a change in 2-OHE1 to 16alpha-OHE1 ratio (r = 0.43; P = 0.015). CONCLUSIONS: A 12-week aerobic exercise training intervention significantly improved aerobic fitness and body composition but did not alter estrogen metabolism in premenopausal women. Interestingly, an increase in lean body mass was associated with a favorable change in 2-OHE1 to 16alpha-OHE1 ratio.

Biological Maturation and Physical Activity in South Korean Adolescent Girls.

INTRODUCTION/PURPOSE: To examine whether body fatness (i.e., body mass index and percent body fat) and psychosocial correlates of physical activity (PA) mediate the relationships between pubertal status and PA and sedentary behavior (SB) among South Korean adolescent girls. METHODS: Pubertal status, body fatness, sport competence, perceived barriers to PA, self-efficacy, parental support for PA, self-reported and step-determined PA, and self-reported SB were assessed among 236 South Korean adolescent girls (mean age = 13.56 ± 1.2 yr). RESULTS: A direct association was identified between pubertal status and PA in all models; more advanced pubertal status predicted lower PA among South Korean adolescents (b = -0.51 to -0.57; P < 0.001). Indirect effects on the pubertal status-PA relationship were also found: body fatness, perceived barriers to PA, and self-efficacy mediated the relationship between pubertal status and PA. Parental support for PA did not moderate the relationship between maturation and PA. SB was not associated with pubertal status. CONCLUSIONS: This study found mediated effects of body fatness, and psychosocial correlates (i.e., perceived barriers to PA, self-efficacy) on the relationship between maturity and PA among South Korean adolescent girls. Efforts to promote PA among South Korean adolescent girls should focus on reducing perceived barriers to PA, and increasing self-efficacy by providing more opportunities to have positive, and enjoyable experiences in PA among early-maturing girls.

Associations between aerobic fitness and estrogen metabolites in premenopausal women.

UNLABELLED: Chronic physical activity may alter estrogen metabolism, a proposed biomarker of breast cancer risk, by causing a shift toward higher 2-OHE1 and lower 16alpha-OHE1 levels. PURPOSE: To investigate the association between an objective indicator of chronic exercise, aerobic fitness, and 2-OHE1 and 16alpha-OHE1 in premenopausal women. METHODS: Women with high aerobic fitness (N=17; VO2max>or=48 mL.kg.min-1) were compared with women with average aerobic fitness (N=13; VO2max

Effect of hydration status on high-intensity rowing performance and immune function.

PURPOSE: This study determined the effect of dehydration and rehydration (DR) on performance, immune cell response, and tympanic temperature after high-intensity rowing exercise. METHODS: Seven oarswomen completed two simulated 2000-m rowing race trials separated by 72 h in a random, cross-over design. One trial was completed in a euhydrated (E) condition and the other using a DR protocol. RESULTS: The DR condition resulted in a 3.33+/-0.14% reduction in body mass (P<.05) over a 24-h period followed by a 2-h rehydration period immediately before the simulated rowing race. There was a greater change in tympanic temperature observed in the DR trial (P<.05). There were increases in the blood concentration of leukocytes, lymphocytes, lymphocyte subsets (CD3+, CD3+/4+, CD3+/8+, CD3-/16+, CD4+/25+; P<.05) and decreases in lymphocyte proliferation and neutrophil oxidative burst activity immediately following the simulated race (P<.05) in both trials. Blood leukocyte and neutrophil concentrations were greater after exercise in the DR trial (P<.05). Whereas most immune measures returned to resting values after 60 min of recovery in both trials, lymphocyte proliferation and the concentrations of CD3+/4+ and CD4+/25+ cells were significantly lower than before exercise. Blood leukocyte and neutrophil concentrations were significantly higher before and after exercise in the E trial. CONCLUSION: The effects of dehydration/rehydration did not negatively influence simulated 2000-m rowing race performance in lightweight oarswomen but did produce a higher tympanic temperature and had a differential effect on blood leukocyte, neutrophil, and natural killer (CD3-/16+) cell concentrations after exercise compared with the euhydrated state.

A randomized controlled crossover trial of the effect of ginseng consumption on the immune response to moderate exercise in healthy sedentary men.

Ginseng is a popular herbal remedy that is reputed to increase resistance to stress and improve immune function. Regular exercise results in acute physiologic stress that affects the immune response. This study was conducted to investigate the effects of daily consumption of a standardized ginsenoside-containing North American ginseng (Panax quinquefolius) extract on immune function before, during, and after a moderate-exercise protocol in healthy sedentary men. Ten healthy males were randomized to receive either ginseng (1125 mg.d-1) or placebo for 35 days. After a 3 month washout period, subjects received the opposite treatment for another 35 days. An exercise test and blood collection were performed at the end of each treatment period. Immune parameters and blood hormone levels were measured before, during, and after the exercise stress protocol. Ginseng treatment reduced the peripheral blood concentration of CD8+ T cells and increased mitogen-stimulated T cell production of interleukin-2 ex vivo. Ginseng had no effect on total white blood cell counts; on concentrations of neutrophils, monocytes, or lymphocytes (CD3+, CD4+, CD16+, CD20+); on lymphocyte proliferation; or on neutrophil oxidative burst. Ginseng did not significantly affect exercise-induced changes in plasma concentrations of lactate, insulin, cortisol, or growth hormone. The consumption of ginseng for 5 weeks had a limited effect on the immune response to an acute exercise protocol.

Effect of elk velvet antler supplementation on the hormonal response to acute and chronic exercise in male and female rowers.

To examine the effects of elk velvet antler supplementation (EVA) combined with training on resting and exercise-stimulated hormonal response, male (n = 25) and female (n = 21) rowers ingested either EVA (560 mg/d) or placebo (PL) during 10 wk of training. VO(2max), 2000 m rowing time, leg and bench press strength were determined before and after 5 and 10 wk of training. Serum hormone levels were measured prior to and 5 and 60 min after a simulated 2000 m rowing race. VO(2max)and strength increased and 2000 m times decreased similarly (P < 0.05) with training. There was no significant difference between the EVA and PL group for any hormonal response. Testosterone (males only) and growth hormone (both genders) were higher 5 min after the simulated race (P < 0.05) but returned to baseline at 60 min. Cortisol was higher 5 and 60 min compared to rest (both genders) (P < 0.05) and was higher 60 min post-exercise following 5 and 10 wk of training. It appears that 10 wk of EVA supplementation does not significantly improve rowing performance nor alter hormonal responses at rest or after acute exercise than training alone.

Energy balance and reproductive function in active women.

Athletes engaged in rigorous training programs expend large amounts of energy and require appropriate energetic compensation to maintain or improve performance. If these exercise regimens are not fueled sufficiently, a negative energy balance will likely emerge and lead to a broad spectrum of menstrual cycle disturbances and less than optimal performance. This review examines the theory and evidence surrounding energy availability and reproductive function. Implications for performance and treatment strategies are also addressed.

Leptin response to short-term fasting in sympathectomized men: role of the SNS.

We studied plasma leptin levels in six people with high-lesion spinal cord injury [SCI; body mass index (BMI) 25.9 +/- 1.5 kg/m(2), age 37 +/- 3.0 yr] and six able-bodied (AB) controls (BMI 29.1 +/- 1.9 kg/m(2), age 35 +/- 3.5 yr) before and after 12, 24, and 36 h of fasting. The plasma leptin levels significantly decreased during 36 h fasting by 48.8 +/- 4.5% (pre: 11.3 +/- 2.3, post: 6.2 +/- 1.5 ng/ml) and 38.6 +/- 7.9% (pre: 7.6 +/- 5.0, post: 4.2 +/- 1.0 ng/ml) in SCI and AB, respectively. Plasma leptin started to decrease at 24 h of fasting in the SCI group, whereas plasma leptin started to decrease at 12 h of fasting in the AB group. The current study demonstrated that plasma leptin decreased with fasting in both SCI and AB groups, with the leptin decrease being delayed in the SCI group. The delayed leptin response to fasting in the SCI group may be because of increased fat mass (%body fat, SCI: 33.8 +/- 3.0, AB: 24.1 +/- 2.9) and sympathetic nervous system dysfunction.

Energy balance and luteal phase progesterone levels in elite adolescent aesthetic athletes.

Menstrual abnormalities are associated with negative energy balance and reduced energy expenditure (REE). To examine this relationship in elite adolescent aesthetic athletes, 3 groups of females (aged 15-18 years) were studied: 10 oligo/amenorrheic athletes (OA), 11 eumenorrheic athletes (EA), and 8 non-athlete controls (C). Components of energy balance, body composition, dietary restraint, pubertal maturation, and luteal phase salivary progesterone were assessed in all groups. Both groups of athletes had a later age of menarche and lower pubertal development score compared to the non-athletes (p < or = .05). With the exception of salivary progesterone (ng/ml; OA = 0. 15 +/- 0.01