Browsing by Author "Badenhorst CE"

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    A contemporary understanding of iron metabolism in active premenopausal females
    (Frontiers Media S.A, 2022) Badenhorst CE; Forsyth AK; Govus AD
    Iron metabolism research in the past decade has identified menstrual blood loss as a key contributor to the prevalence of iron deficiency in premenopausal females. The reproductive hormones estrogen and progesterone influence iron regulation and contribute to variations in iron parameters throughout the menstrual cycle. Despite the high prevalence of iron deficiency in premenopausal females, scant research has investigated female-specific causes and treatments for iron deficiency. In this review, we provide a comprehensive discussion of factors that influence iron status in active premenopausal females, with a focus on the menstrual cycle. We also outline several practical guidelines for monitoring, diagnosing, and treating iron deficiency in premenopausal females. Finally, we highlight several areas for further research to enhance the understanding of iron metabolism in this at-risk population.
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    Athlete Preferences for Nutrition Education: Development of and Findings from a Quantitative Survey.
    (MDPI (Basel, Switzerland), 2023-05-29) Solly H; Badenhorst CE; McCauley M; Slater GJ; Gifford JA; Erueti B; Beck KL; Nieman DC
    Nutrition education (NE) is one of several strategies aimed at enhancing the dietary intake of athletes. This study investigated NE preferences of New Zealand and Australian athletes competing nationally and internationally. Athletes (n = 124, 22 (18, 27) years, female 54.8%) from 22 sports completed an online survey, with responses analysed using descriptive statistics. Teaching techniques considered 'extremely effective' were life examples (47.6% of athletes), hands-on activities (30.6%), and discussions with a facilitator (30.6%). Setting personal nutrition goals was important to most athletes (83.9%), along with two-way feedback with a facilitator (75.0%). General nutrition topics considered 'essential' were energy requirements (52.9%), hydration (52.9%), and nutrient deficiencies (43.3%). Performance topics considered 'essential' were recovery (58.1%), pre-exercise nutrition (51.6%), nutrition during exercise (50.0%), and energy requirements for training (49.2%). Athletes preferred a 'combination of in-person group and one-on-one sessions' (25% of athletes), 'one-on one sessions' (19.2%) and 'in-person group sessions' (18.3%), with only 13.3% interested in 'exclusively online delivery'. Sessions of 31-60 min (61.3% of athletes) held monthly (37.5%) and undertaken with athletes of the same sporting calibre (61.3%) were favoured by the participants. The preferred facilitator was a performance dietitian or nutritionist (82.1% of athletes), who had knowledge of the sport (85.5%), experience in sports nutrition (76.6%), and credibility (73.4%). This research provides novel insights into the factors that need to be considered when designing and implementing nutrition education for athletes.
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    Do E2 and P4 contribute to the explained variance in core temperature response for trained women during exertional heat stress when metabolic rates are very high?
    (Springer Nature, 2022-10) Zheng H; Badenhorst CE; Lei T-H; Che Muhamed AM; Liao Y-H; Fujii N; Kondo N; Mündel T
    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 (𝑅⎯⎯⎯⎯2: 41% core temperature at the start of work trial, 𝑅⎯⎯⎯⎯2: 15% power output, 𝑅⎯⎯⎯⎯2: 4% [E2]) and 44% of the variance in mean power output (𝑅⎯⎯⎯⎯2: 35% peak aerobic power, 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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    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 T
    PURPOSE: 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.
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    Effect of Amino Acid Supplementation on Iron Regulation after Endurance Exercise.
    (MDPI (Basel, Switzerland), 2023-11-25) Lin C-A; Hayashi N; Badenhorst CE; Goto K; Rowlands D
    The purpose of this study was to determine the effects of pre-exercise amino acid (AA) supplementation on post-exercise iron regulation. Ten healthy males participated under two different sets of conditions in a randomized, double-blind, crossover design with a washout period of at least 21 days. Participants received either an AA supplement or placebo (PLA) for five consecutive days (4 g/dose, 3 doses/day). On the sixth day, participants ran on a treadmill for 60 min at 70% of maximal oxygen consumption (V˙O2max). Venous blood samples were collected before (baseline), immediately after, and 1 and 3 h after exercise. The serum hepcidin levels increased significantly 3 h post-exercise in both trials when compared to the baseline (p < 0.001), but the levels were not different between trials. The plasma interleukin-6 (IL-6) level significantly increased immediately after exercise compared to the baseline (p < 0.001) and was significantly higher in the AA trial than in the PLA trial (p = 0.014). Moreover, the exercise-induced increase in serum glycerol level was significantly higher in the AA trial (21.20 ± 3.98 mg/L) than in the PLA trial (17.28 ± 4.47 mg/L, p = 0.017). No significant differences were observed between the AA and PLA trials for serum iron, ferritin, and total ketone body levels (p > 0.05). In conclusion, five days of AA supplementation augmented exercise-induced increases in IL-6 and glycerol in healthy males. However, it did not affect post-exercise iron status or regulation.
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    Improving menstrual health literacy in sport.
    (Elsevier B.V., 2023-07-19) McGawley K; Sargent D; Noordhof D; Badenhorst CE; Julian R; Govus AD
    Menstrual health represents a state of complete physical, mental, and social well-being in relation to a woman's menstrual cycle. From a health literacy perspective, knowledge acquisition and expertise are dependent upon the degree to which an individual can find, access, understand, critically analyse, and apply health information. Therefore, menstrual health literacy can be used to describe the state of knowledge acquisition and application specific to menstrual health-related issues. Menstrual health literacy is low among female athletes, their coaches, and practitioners, and few evidence-informed education or implementation strategies exist to improve menstrual health literacy in sport. Moreover, athletes seldom discuss their menstrual cycles or hormonal contraceptive use with their coaches, despite experiencing menstrual symptoms and/or disturbances and perceiving their menstrual cycles/hormonal contraceptive use to affect performance. Barriers to communication about menstrual cycle- and hormonal contraceptive-related topics include a perceived lack of knowledge among athletes, coaches, and practitioners, concerns about how conversations on these issues will affect interpersonal relationships, and a lack of formal and informal discussion forums. Whilst evidence relating to the effects of the menstrual cycle phase and hormonal contraceptive use on training and performance is currently limited, with existing studies often lacking methodological rigour, impactful steps can still be made to support female athletes. This cornerstone review highlights the current state of menstrual health literacy among athletes, coaches, and practitioners, and provides recommendations for improving menstrual health literacy in sport.
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    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 T
    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 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.
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    Physical Activity, Mental Health and Wellbeing during the First COVID-19 Containment in New Zealand: A Cross-Sectional Study
    (MDPI (Basel, Switzerland), 2021-11) O'Brien WJ; Badenhorst CE; Draper N; Basu A; Elliot CA; Hamlin MJ; Batten J; Lambrick D; Faulkner J
    Strategies implemented worldwide to contain COVID-19 outbreaks varied in severity across different countries, and established a new normal for work and school life (i.e., from home) for many people, reducing opportunities for physical activity. Positive relationships of physical activity with both mental and physical health are well recognised, and therefore the aim was to ascertain how New Zealand’s lockdown restrictions impacted physical activity, mental health and wellbeing. Participants (n = 4007; mean ± SD: age 46.5 ± 14.7 years, 72% female, 80.7% New Zealand European) completed (10–26 April 2020) an online amalgamated survey (Qualtrics): International Physical Activity Questionnaire: Short Form; Depression, Anxiety and Stress Scale-9; World Health Organisation-Five Well-Being Index; Stages of Change Scale. Positive dose–response relationships between physical activity levels and wellbeing scores were demonstrated for estimates that were unadjusted (moderate activity OR 3.79, CI 2.88–4.92; high activity OR 8.04, CI 6.07–10.7) and adjusted (confounding variables: age, gender, socioeconomic status, time sitting and co-morbidities) (moderate activity 1.57, CI 1.11–2.52; high activity 2.85, CI 1.97–4.14). The study results support previous research demonstrating beneficial effects of regular physical activity on mental health and wellbeing. Governments may use these results to promote meeting physical activity guidelines in order to protect mental health and wellbeing during the ongoing COVID-19 restrictions and future pandemics.
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    Physical Activity, Mental Health and Wellbeing of Adults within and during the Easing of COVID-19 Restrictions, in the United Kingdom and New Zealand
    (MDPI (Basel, Switzerland), 2022-02) Faulkner J; O'Brien WJ; Stuart B; Stoner L; Batten J; Wadsworth D; Askew CD; Badenhorst CE; Byrd E; Draper N; Elliot C; Fryer S; Hamlin MJ; Jakeman JR; Mackintosh KA; McNarry MA; Mitchelmore A; Ryan-Stewart H; Saynor Z; Schaumberg MA; Spiegelhalter E; Stone K; Lambrick D
    Physical activity (PA) participation was substantially reduced at the start of the COVID-19 pandemic. The purpose of this study was to assess the association between PA, mental health, and wellbeing during and following the easing of COVID-19 restrictions in the United Kingdom (UK) and New Zealand (NZ). In this study, 3363 adults completed online surveys within 2–6 weeks of initial COVID-19 restrictions (April/May 2020) and once restrictions to human movement had been eased. Outcome measures included the International Physical Activity Questionnaire Short-Form, Depression Anxiety and Stress Scale-9 (mental health) and World Health Organisation-5 Wellbeing Index. There were no differences in PA, mental health or wellbeing between timepoints (p > 0.05). Individuals engaging in moderate or high volume of PA had significantly better mental health (−1.1 and −1.7 units, respectively) and wellbeing (11.4 and 18.6 units, respectively) than individuals who engaged in low PA (p < 0.001). Mental health was better once COVID-19 restrictions were eased (p < 0.001). NZ had better mental health and wellbeing than the UK (p < 0.001). Participation in moderate-to-high volumes of PA was associated with better mental health and wellbeing, both during and following periods of COVID-19 containment, compared to participation in low volumes of PA. Where applicable, during the current or future pandemic(s), moderate-to-high volumes of PA should be encouraged.
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    Relationship between vitamin D, iron, and hepcidin in premenopausal females, potentially confounded by ethnicity.
    (Springer Nature, 2023-08-29) Greenwood A; Von Hurst PR; Beck KL; Mazahery H; Lim K; Badenhorst CE
    PURPOSE: To investigate the associations between vitamin D, hepcidin, and iron status in premenopausal females of different ethnic cohorts residing in Auckland, New Zealand (NZ). METHODS: A total of 160 females aged 18-45 years participated in a cross-sectional study. Demographics, body composition, serum 25(OH)D, inflammatory markers (C-reactive protein and interleukin-6, IL-6), and iron biomarkers (serum ferritin, haemoglobin, soluble transferrin receptor, and hepcidin) were measured. Comparisons between parametric, non-parametric, and categorical variables were completed by using one-way ANOVA, Kruskal-Wallis, and Chi-squared tests, respectively. ANCOVA was used to compare serum 25(OH)D across iron parameter categories. RESULTS: Of the 160 participants, 60 were NZ European, 67 were South Asian, and 33 were from the 'other' ethnic groups. South Asians had significantly higher body fat percentage (BF%) and IL-6 concentration (38.34% and 1.66 pg·mL-1, respectively), compared to NZ Europeans (27.49% and 0.63 pg·mL-1, respectively, p < 0.001). South Asians had significantly lower 25(OH)D concentrations compared to NZ Europeans (33.59 nmol·L-1 vs 74.84 nmol·L-1, p < 0.001). In NZ Europeans, higher 25(OH)D concentration was seen in those with lower (≤ 3.5 nM) hepcidin concentration, p = 0.0046. In South Asians, higher 25(OH)D concentration was seen in those with higher (> 3.5 nM) hepcidin concentrations, p = 0.038. There were no associations between serum 25(OH)D and serum ferritin. CONCLUSION: Within South Asian women, an unexpected positive relationship between 25(OH)D and hepcidin concentration was observed which may be due to significantly higher IL-6 concentrations, BF%, and lower 25(OH)D concentrations. Future research is required to confirm these observations in this ethnic cohort.
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    The Hydrating Effects of Hypertonic, Isotonic and Hypotonic Sports Drinks and Waters on Central Hydration During Continuous Exercise: A Systematic Meta-Analysis and Perspective
    (Springer Nature, 2022-02) Rowlands DS; Kopetschny BH; Badenhorst CE
    Background Body-fluid loss during prolonged continuous exercise can impair cardiovascular function, harming performance. Delta percent plasma volume (dPV) represents the change in central and circulatory body-water volume and therefore hydration during exercise; however, the effect of carbohydrate–electrolyte drinks and water on the dPV response is unclear. Objective To determine by meta-analysis the effects of ingested hypertonic (> 300 mOsmol kg−1), isotonic (275–300 mOsmol kg−1) and hypotonic (< 275 mOsmol kg−1) drinks containing carbohydrate and electrolyte ([Na+] < 50 mmol L−1), and non-carbohydrate drinks/water (< 40 mOsmol kg−1) on dPV during continuous exercise. Methods A systematic review produced 28 qualifying studies and 68 drink treatment effects. Random-effects meta-analyses with repeated measures provided estimates of effects and probability of superiority (p+) during 0–180 min of exercise, adjusted for drink osmolality, ingestion rate, metabolic rate and a weakly informative Bayesian prior. Results Mean drink effects on dPV were: hypertonic − 7.4% [90% compatibility limits (CL) − 8.5, − 6.3], isotonic − 8.7% (90% CL − 10.1, − 7.4), hypotonic − 6.3% (90% CL − 7.4, − 5.3) and water − 7.5% (90% CL − 8.5, − 6.4). Posterior contrast estimates relative to the smallest important effect (dPV = 0.75%) were: hypertonic-isotonic 1.2% (90% CL − 0.1, 2.6; p+ = 0.74), hypotonic-isotonic 2.3% (90% CL 1.1, 3.5; p+ = 0.984), water-isotonic 1.3% (90% CL 0.0, 2.5; p+ = 0.76), hypotonic-hypertonic 1.1% (90% CL 0.1, 2.1; p+ = 0.71), hypertonic-water 0.1% (90% CL − 0.8, 1.0; p+ = 0.12) and hypotonic-water 1.1% (90% CL 0.1, 2.0; p+ = 0.72). Thus, hypotonic drinks were very likely superior to isotonic and likely superior to hypertonic and water. Metabolic rate, ingestion rate, carbohydrate characteristics and electrolyte concentration were generally substantial modifiers of dPV. Conclusion Hypotonic carbohydrate–electrolyte drinks ingested continuously during exercise provide the greatest benefit to hydration.
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    The Menstrual Health Manager (MHM): A Resource to Reduce Discrepancies Between Science and Practice in Sport and Exercise.
    (Springer Nature, 2024-06-21) Badenhorst CE
    Inadequate research on female health and performance; the complexity of the research; low menstrual health literacy of athletes, coaches, and support staff; and ethical and cultural sensitivities are all recognized as barriers to effective health monitoring for females in sports. Frameworks have been developed for academics to follow to help improve the quality of female-specific research. However, a similar resource that enables correct terminology, and use of health monitoring techniques has not been provided for sporting organizations, coaches, support staff or athletes. Therefore, this critical commentary presents a new resource, the Menstrual Health Manager. This resource may be used to determine the level of menstrual health monitoring detail that may be used by organisations, coaches or athletes, and specifies what reproductive health details the data will provide. This resource aims to provide organizations and coaches with a means of understanding the data that inform their decisions for female athletes. Utilization of this resource may aid in the consistent use of terminology and methods for female-specific health monitoring in both sports and research.