The current study investigated whether ambient heat augments the inflammatory and post-exercise hepcidin response in women, and if menstrual phase and/or self-pacing modulate these physiological effects. Eight trained females (age: 37±7 y; VO2max: 46±7 mL∙kg-1∙min-1; peak power output: 4.5±0.8 W∙kg-1) underwent 20 min of fixed-intensity cycling (100 and 125 W) followed by a 30-min work trial (≈75% VO2max) in a moderate (MOD: 20±1 °C, 53±8% relative humidity) and warm-humid (WARM: 32±0 °C, 75±3% relative humidity) environment in both their early follicular (days 5±2) and mid-luteal (days 21±3) phases. Mean power output was 5±4 W higher in MOD than in WARM (p=0.02) such that the difference in core temperature rise was limited between environments (-0.29±0.18 °C in MOD, p<0.01). IL-6 and hepcidin both increased post-exercise (198% and 38%, respectively), however, neither were affected by ambient temperature or menstrual phase (all p>0.15). Multiple regression analysis demonstrated that the IL-6 response to exercise was explained by leukocyte and platelet count (r2=0.72, p<0.01) and the hepcidin response to exercise was explained by serum iron and ferritin (r2=0.62, p<0.01). During exercise participants almost matched their fluid loss (0.48±0.18 kg·h-1) with water intake (0.35±0.15 L·h-1) such that changes in body mass (-0.3±0.3%) and serum osmolality (0.5±2.0 mOsm·kg-1) were minimal or negligible, indicating a behavioral fluid-regulatory response. These results indicate that trained, iron sufficient women suffer no detriment to their iron regulation in response to exercise with acute ambient heat stress or between menstrual phases on account of a performance-physiological trade-off.
Measurement error(s) of exercise tests for women are severely lacking in the literature. The purpose of this investigation was to 1) determine whether ovulatory status or ambient environment were moderating variables when completing a 30-min self-paced work trial, and 2) provide test-retest norms specific to athletic women. A retrospective analysis of three heat stress studies was completed using 33 female participants (31±9 y, 54±10 mL min-1 kg-1) that yielded 130 separate trials. Participants were classified as ovulatory (n=19), anovulatory and/or luteal phase-deficient (n=4) and oral contraceptive pill users (n=10). Participants completed trials ~2 weeks apart in their (quasi-) early follicular and mid-luteal phases in two of moderate (1.3±0.1 kPa, 20.5±0.5 °C, 18 trials), warm-dry (2.2±0.2 kPa, 34.1±0.2 °C, 46 trials) or warm-humid (3.4±0.1 kPa, 30.2±1.1 °C, 66 trials) environments. We quantified reliability using limits of agreement, intraclass correlation coefficient (ICC), Pearson's correlation coefficient (r), standard error of measurement (SEM) and coefficient of variation (CV). Test-retest reliability was high, clinically-valid (ICC=0.90, r=0.83, both p<0.01) and acceptable with a mean CV of 4.7%, SEM of 3.8 kJ (2.1 W) and reliable bias of -2.1 kJ (-1.2 W). The various ovulatory status and contrasting ambient conditions had no appreciable effect on reliability. These results indicate that athletic women can perform 30-min self-paced work trials ~2 weeks apart with an acceptable and low variability irrespective of their hormonal status or heat-stressful environments.
A Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) pretreatment technique combined with HPLC–MS/MS was established to detect 26 pesticides in traditional Chinese medicinal leeches. The sample was extracted by acetonitrile solution with sodium acetate-0.1% (v/v) acetic acid as a buffer system, then cleaned up by a mixture of 750 mg of MgSO4, 150 mg of C18, and 150 mg of PSA, separated by an ACQUITY BEH C18 column, and determined in the dynamic multiple reaction mode. Under the optimized conditions, the peak areas of the 26 pesticides in leeches showed good linearity (r > 0.99) between their mass concentrations from 1 to 100 μg/L. At the spike levels of 10, 20, and 100 μg/kg, the recoveries of 26 pesticides in leeches were 72.9–101.6% with an RSD of 1.1–12.8%, an LOQ of 10 μg/kg, and an LOD of 0.1–5.4 μg/kg. This method is easy, rapid, sensitive, and practical and meets the requirements of pesticide residue detection standards.
Purpose Women remain underrepresented in the exercise thermoregulation literature despite their participation in leisure-time and occupational physical activity in heat-stressful environments continuing to increase. Here, we determined the relative contribution of the primary ovarian hormones (estrogen [E2] and progesterone [P4]) alongside other morphological (e.g., body mass), physiological (e.g., sweat rates), functional (e.g., aerobic fitness) and environmental (e.g., vapor pressure) factors in explaining the individual variation in core temperature responses for trained women working at very high metabolic rates, specifically peak core temperature (Tpeak) and work output (mean power output). Methods Thirty-six trained women (32 ± 9 year, 53 ± 9 ml·kg−1·min−1), distinguished by intra-participant (early follicular and mid-luteal phases) or inter-participant (ovulatory vs. anovulatory vs. oral contraceptive pill user) differences in their endogenous E2 and P4 concentrations, completed a self-paced 30-min cycling work trial in warm–dry (2.2 ± 0.2 kPa, 34.1 ± 0.2 °C, 41.4 ± 3.4% RH) and/or warm–humid (3.4 ± 0.1 kPa, 30.2 ± 1.2 °C, 79.8 ± 3.7% RH) conditions that yielded 115 separate trials. Stepwise linear regression was used to explain the variance of the dependent variables. Results Models were able to account for 60% of the variance in Tpeak ($$\overline{R }$$ R ¯ 2: 41% core temperature at the start of work trial, $$\overline{R }$$ R ¯ 2: 15% power output, $$\overline{R }$$ R ¯ 2: 4% [E2]) and 44% of the variance in mean power output ($$\overline{R }$$ R ¯ 2: 35% peak aerobic power, $$\overline{R }$$ R ¯ 2: 9% perceived exertion). Conclusion E2 contributes a small amount toward the core temperature response in trained women, whereby starting core temperature and peak aerobic power explain the greatest variance in Tpeak and work output, respectively.
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