Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
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Item Does chronic oral contraceptive use detrimentally affect C-reactive protein or iron status for endurance-trained women?(Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society., 2023-07-24) Badenhorst CE; Govus AD; Mündel TPURPOSE: Chronic use of the oral contraceptive pill (OCP) is reported to increase C-reactive protein (CRP) levels and increase the risk of cardiovascular disease in premenopausal females. METHODS: A secondary analysis of data from two research studies in eumenorrheic (n = 8) and OCP (n = 8) female athletes. Basal CRP and iron parameters were included in the analysis. Sample collection occurred following a standardized exercise and nutritional control for 24 h. Eumenorrheic females were tested in the early-follicular and mid-luteal phases, and the OCP users were tested in quasi-follicular and quasi-luteal phases (both active pill periods). RESULTS: A main effect for group (p < 0.01) indicated that average CRP concentration was higher in OCP users compared with eumenorrheic females, regardless of the day of measurement within the cycle. Results demonstrate a degree of iron parameters moderation throughout the menstrual cycle that is influenced by basal CRP levels; however, no linear relationship with CRP, serum iron, and ferritin was observed. CONCLUSIONS: Basal CRP values were consistently higher in the OCP group despite participants being in a rested state. These results may indicate a potential risk of cardiovascular disease in prolonged users of the OCP when compared to eumenorrheic female athletes.Item Measurement error of self-paced exercise performance in athletic women is not affected by ovulatory status or ambient environment(American Physiological Society, 2021-11) Zheng H; Badenhorst CE; Lei T-H; Muhamed AMC; Liao Y-H; Amano T; Fujii N; Nishiyasu T; Kondo N; Mündel TMeasurement 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 yr, 54 ± 10 mL·min−1·kg−1) that yielded 130 separate trials. Participants were classified as ovulatory (n = 19), anovulatory (n = 4), and oral contraceptive pill users (n = 10). Participants completed trials ∼2 wk apart in their (quasi-) early follicular and midluteal 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), standard error of measurement (SEM), and coefficient of variation (CV). Test-retest reliability was high, clinically valid (ICC = 0.90, 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 wk apart with an acceptable and low variability irrespective of their hormonal status or heat-stressful environments. NEW & NOTEWORTHY This study highlights that aerobically trained women perform 30-min self-paced work trials ∼2 wk apart with acceptably low variability and their hormonal/ovulatory status and the introduction of greater ambient heat and humidity do not moderate this measurement error.