Decreased maximal aerobic capacity with use of a triphasic oral contraceptive in highly active women: a randomised controlled trial

Auditing the representation of hormonal contraceptives in studies assessing exercise performance in women

Hormonal contraceptive (HC) users have a different ovarian hormonal profile compared to eumenorrheic women. Due to the prevalence of HC use amongst sportswomen, there has been increased research efforts to understand their impact on exercise performance. The aim was to audit this research. Studies identified were assessed for HC type, athlete calibre, performance outcome, study design, and quality of methodological control regarding ovarian hormonal profiles. Sixty-eight different HCs were reported across 61 studies. Monophasic combined oral contraceptive (OCP) pills represented 60% of HCs, followed by other pills [34%, phasic-combined, progestogen-only, and un-specified], phasic and long acting reversible contraceptives [5%, vaginal ring, patch, implant, injection, intrauterine system] and unspecified HCs (1%). Eleven percent of participants using HCs were classified as highly trained or elite/international with no participants being classed as world class. Whilst the number of studies involving HCs has increased two-fold over the past decade, the number of studies ranked as gold standard has not increased (HC; 2003-57%, 2011-55%, 2022-43%. OCP; 2003-14%, 2011-17%, 2022-12%). Future research assessing HCs and exercise performance should adopt high-quality research designs and include a broader range of HCs in highly trained to world-class populations to increase the reach and impact of research in this area.

Hormonal contraception for female athletes presents special needs and concerns

PURPOSE

Oral contraceptives (OCs) are commonly used by female athletes raising concerns regarding the possible adverse effects of OCs on physical performance, musculoskeletal injuries, and bone density. We aimed to review all current studies on the physiological effects of OCs in physically active women.

MATERIALS AND METHODS

A review of literature in electronic search in PubMed and Google Scholar databases from December 2002 to December 2022 using relevant keywords. The reference lists of the articles found eligible were also reviewed.

RESULTS

Out of 344 articles in the initial database, 54 clinical studies were eligible for inclusion in our literature review. OCs are used by about two-thirds of female athletes. Current research suggests that OCs' effects on endurance performance and muscle strength are mostly reassuring. OCs do not seem to have a major negative impact on bone health or sports injuries. In fact, new data suggests that they may even significantly reduce the risk of anterior cruciate ligament (ACL) injury.

CONCLUSIONS

OCs can be safely used by young female athletes, who may also benefit from better menstrual cycle control. OCs offer newly realised protection from ACL injuries. The use of OCs must be carefully individualised according to their preferences, expectations, and experience.

The influence of the menstrual cycle and hormonal contraceptives on cardiorespiratory fitness in physically active women: A systematic review and meta-analysis

Objective

To systematically review and summarize the existing evidence related to the influence of the menstrual cycle (MC) and hormonal contraceptive (HC) use on V˙O_2max in physically active women.

Methods

This systematic review and meta-analysis conforms to the PRISMA statement guidelines. Four (sub-)meta-analyses were performed. Two focused on longitudinal studies examining the same women several times to compare the V˙O_2max during the different menstrual phases or oral contraceptive (OC) use and withdrawal. Two meta-analyses examined if there is a difference in V˙O_2max between OC users and normally menstruating women by analyzing cross-sectional studies assigning physically active women to one of these two groups as well as intervention-based studies (cross-over studies, randomized controlled trials considering only the data of the intervention group) comparing women intra-individually with and without OCs.

Results

Nine of the included studies (107 women) evaluated the influence of the MC, five studies (69 women) the impact of OCs on V˙O_2max, and six studies investigated both topics (88 women). A mean difference of V˙O_2max -0.03 ml/kg/min (95%CI -1.06 to 1.01) between the early follicular and luteal menstrual phase was observed. Between the active and inactive phases of OCs, a mean difference of -0.11 ml/kg/min (95%CI -2.32 to 2.10) was found. The inter-individual comparison of naturally menstruating women and OC users showed a mean difference in V˙O_2max of 0.23 ml/kg/min (95% CI -2.33 to 2.79) in favor of OC use. The intra-individual comparison of the same women showed a mean decrease in V˙O_2max of -0.84 ml/kg/min (95% CI -2.38 to 0.70) after a new start with OCs.

Conclusions

Our meta-analyses showed no effects of the MC or the OCs on V˙O_2max. More high-quality studies are needed determining the MC phases more precisely, including OCs with the current standard formulations and comparing the influence of different progestins.

Cardiorespiratory Insufficiency and Performance Fatigability in Women with Systemic Lupus Erythematosus

Purpose

Patients with systemic lupus erythematosus (SLE) experience excessive, debilitating fatigue with previously reported evidence of etiologically mediated cardiorespiratory impairments. Performance fatigability provides a precise characterization of fatigue as it can be quantified objectively as a function of time, frequency, and/or duration. Nevertheless, little consideration has been given to understanding performance fatigability and its physiological determinants in those with SLE. The purpose of this study was to characterize performance fatigability in patients with SLE, utilizing measures surrounding the anaerobic threshold, with emphasis on cardiorespiratory impairment as a potential mediating factor.

Methods

This was a case-control study design. 44 physically inactive women, 26 with SLE and 18 controls, completed a treadmill cardiopulmonary exercise test to volitional exhaustion.

Results

There were no significant differences in age (SLE 34.8(9.0) vs Control 36.9(7.3) yrs; p=0.422) between groups. BMI (SLE 27.1(5.4) vs Control 23.8(5.2) kg/m2; p=0.045) was significantly higher in the SLE vs Control group. Resting heart rate (SLE 68(16) vs Control 78(15) bpm; p=0.040) was significantly lower in the SLE compared to the Control group. The VO2 corresponding to the anaerobic threshold (AT-VO2), used to identify the onset of exercise-induced fatigue, was significantly lower in women with SLE than in controls (SLE 12.4(3.1) vs Control 16.4(2.2) ml/kg/min; p<0.001), as was AT-stage (SLE 2.5(0.90) vs Control 3.4(0.78); p=0.002). Additionally, Fatigue Severity Score (FSS) was highly and inversely correlated with AT-VO2 (rho=-0.615; p<0.001) and FSS was highly correlated with Functional Aerobic Impairment Index (FAI; rho=0.663; p<0.001).

Conclusion

This study underscores severe performance fatigability in patients with SLE and its link to cardiorespiratory insufficiency. Physiological presentation of performance fatigability was observed during very low intensities of exercise, emphasizing the negative impact it may have on physical function in this population.

"I hardly have a problem […] I have my period quite rarely too": Female football players' and their coaches' perceptions of barriers to communication on menstrual cycle

Introduction

Symptoms related to the menstrual cycle (MC) affect the performance level and health of female athletes in various ways. Previous research has reported MC symptoms such as pain, mood disturbance, reduced coordination and competition distraction as well as diminished performance levels and an increased injury risk among female elite athletes. Despite this, the coach-athlete communication related to the female hormonal cycle is limited. The aim of the present study was to explore the perceptions of MC communication in a group of junior elite football players and their male coaches in a case study of one youth football team in a specific club in Norway.

Methods

The study used a qualitative approach with semi-structured interviews. In total, 8 female junior elite players (aged 16-20) from a Norwegian football team and 2 of their male coaches participated in the study.

Results

The data analysis revealed two main communication barriers: 1. interpersonal barriers (e.g., false assumptions about the coach/athletes and social discomfort) and 2. knowledge barriers (e.g., unaware/perceptions of insufficient knowledge levels).

Discussion

As the players seemed to be unaware of their insufficient MC knowledge (e.g., failed to see a connection between the MC and their health and performance level), the coaches perceived their knowledge as insufficient and coped mainly by outsourcing MC communication to female staff and apps. Hence, the MC communication was hindered by both the athletes and the coaches (e.g., mutual avoidance). In line with previous research, this study supports that there is a need for developing effective strategies to overcome the interpersonal barriers and knowledge gaps.

Effects of oral contraceptive use on muscle strength, muscle thickness, and fiber size and composition in young women undergoing 12 weeks of strength training: a cohort study

BACKGROUND

It is suspected that hormonal fluctuations during menstruation may cause different responses to strength training in women who use oral contraceptives (OC) versus those who do not. However, previous studies that investigated the existence of such differences produced conflicting results. In this study, we hypothesized that OC use has no effect on muscle strength and hypertrophy among women undergoing strength training. Thus, we compared the differences in muscle strength and thickness among women who used OCs and those who did not.

METHODS

We investigated the influence of OC use on muscle strength (Fmax), muscle thickness (Mtk), type 1-to-type 2 muscle fiber (NO) ratio, muscle fiber thickness (MFT), and nuclear-to-fiber (N/F) ratio. Seventy-four healthy young women (including 34 who used OCs and 40 who did not) underwent 12 weeks of submaximal strength training, after which Fmax was evaluated using a leg-press machine with a combined force and load cell, while Mtk was measured using real-time ultrasonography. Moreover, the NO ratio, MFT, and N/F ratio were evaluated using muscle needle biopsies.

RESULTS

Participants in the non-OC and OC groups experienced increases in Fmax (+ 23.30 ± 10.82 kg and + 28.02 ± 11.50 kg respectively, p = 0.073), Mtk (+ 0.48 ± 0.47 cm2 and + 0.50 ± 0.44 cm2 respectively, p = 0.888), Fmax/Mtk (+ 2.78 ± 1.93 kg/cm2 and + 3.32 ± 2.37 kg/cm2 respectively, p = 0.285), NO ratio (type 2 fibers: + 1.86 ± 6.49% and - 4.17 ± 9.48% respectively, p = 0.169), MFT (type 2 fibers: + 7.15 ± 7.50 µm and + 4.07 ± 9.30 µm respectively, p = 0.435), and N/F ratio (+ 0.61 ± 1.02 and + 0.15 ± 0.97 respectively, p = 0.866) after training. There were no significant differences between the non-OC and OC groups in any of these parameters (p > 0.05).

CONCLUSIONS

The effects of 12 weeks of strength training on Fmax, muscle thickness, muscle fiber size, and composition were similar in young women irrespective of their OC use.

"Do Elite Sport First, Get Your Period Back Later." Are Barriers to Communication Hindering Female Athletes?

Competitive female athletes perceive their hormonal cycles to affect their training, competition performance and overall well-being. Despite this, athletes rarely discuss hormonal-cycle-related issues with others. The aim of this study was to gain an in-depth understanding of the perceptions and experiences of endurance athletes and their coaches in relation to barriers to athlete-coach communication about female hormonal cycles. Thirteen Swedish national-/international-level female cross-country skiers (age 25.8 ± 3.6 y) and eight of their coaches (two women and six men; age 47.8 ± 7.5 y) completed an online survey relating to their educational background, prior knowledge about female hormonal cycles and a coach-athlete relationship questionnaire (CART-Q). They then participated in an online education session about female hormonal cycles and athletic performance before participating in semi-structured focus-group interviews. Thematic analyses revealed three main barriers to communication: knowledge, interpersonal, and structural. In addition, the results suggested that a good coach-athlete relationship may facilitate open communication about female hormonal cycles, while low levels of knowledge may hinder communication. To overcome the perceived barriers to communication, a model is proposed to improve knowledge, develop interpersonal relationships and strengthen structural systems through educational exchanges and forums for open discussion.

Strength Performance Across the Oral Contraceptive Cycle of Team Sport Athletes: A Cross-Sectional Study

Oral contraceptive pills (OCP) are very popular in female athletes not only for contraceptive effects but also due to the possibility of cycle manipulation. Moreover, it is debatable whether the manipulation of the menstrual cycle has a beneficial effect on exercise performance. Therefore, the aim of this study was to investigate potential differences in knee-extensor and flexor strength performance of first division team sport athletes between phases of the oral contraceptive cycle. Sixteen female handball players (age: 23.3 ± 3.1 years; body mass: 67.0 ± 8.52 kg; body stature: 1.68 ± 0.05 m) using a monophasic OCP participated in strength performance tests, once during OCP consumption (CONS) and once during withdrawal (WITH). Tests were performed on a dynamometer to measure knee-extensor and flexor maximal voluntary isokinetic and isometric torque. Prior to each test, body mass was assessed, and venous blood samples were collected. Wilcoxon signed-rank test and magnitude-based inferences have been conducted to analyze differences between WITH and CONS. Significance was accepted at P < 0.05. No significant differences between oral contraceptive cycle phases of knee-extensor and flexor strength parameters and body mass have been indicated (all at P > 0.05). Follicle-stimulating hormone (FSH) (P = 0.001) and luteinizing hormone (P = 0.013) were significantly higher in WITH, whereby estradiol and progesterone showed no significant difference between phases (both at P > 0.05). These results support the notion that knee-extensor and flexor isokinetic and isometric strength performance does not differ between phases of oral contraceptive cycle in well-trained team sport athletes. OCP intake is suggested to cause a stable but downregulated hormone cycle, which has no effect on knee-extensor and flexor strength when comparing oral contraceptive cycle phases. Therefore, manipulation of the female cycle using OCP in order to achieve a higher knee-extensor and flexor strength performance does not seem to be justified; however, it is currently unclear if cycle manipulation might affect other physiological systems.

The Specificities of Elite Female Athletes: A Multidisciplinary Approach

Female athletes have garnered considerable attention in the last few years as more and more women participate in sports events. However, despite the well-known repercussions of female sex hormones, few studies have investigated the specificities of elite female athletes. In this review, we present the current but still limited data on how normal menstrual phases, altered menstrual phases, and hormonal contraception affect both physical and cognitive performances in these elite athletes. To examine the implicated mechanisms, as well as the potential performances and health risks in this population, we then take a broader multidisciplinary approach and report on the causal/reciprocal relationships between hormonal status and mental and physical health in young (18-40 years) healthy females, both trained and untrained. We thus cover the research on both physiological and psychological variables, as well as on the Athlete Biological Passport used for anti-doping purposes. We consider the fairly frequent discrepancies and summarize the current knowledge in this new field of interest. Last, we conclude with some practical guidelines for eliciting improvements in physical and cognitive performance while minimizing the health risks for female athletes.

Sex differences and considerations for female specific nutritional strategies: a narrative review

Although there is a plethora of information available regarding the impact of nutrition on exercise performance, many recommendations are based on male needs due to the dominance of male participation in the nutrition and exercise science literature. Female participation in sport and exercise is prevalent, making it vital for guidelines to address the sex-specific nutritional needs. Female hormonal levels, such as estrogen and progesterone, fluctuate throughout the mensural cycle and lifecycle requiring more attention for effective nutritional considerations. Sex-specific nutritional recommendations and guidelines for the active female and female athlete have been lacking to date and warrant further consideration. This review provides a practical overview of key physiological and nutritional considerations for the active female. Available literature regarding sex-specific nutrition and dietary supplement guidelines for women has been synthesized, offering evidenced-based practical information that can be incorporated into the daily lives of women to improve performance, body composition, and overall health.

Hormonal Contraceptive Use Does Not Affect Strength, Endurance, or Body Composition Adaptations to Combined Strength and Endurance Training in Women

ABSTRACT

Myllyaho, MM, Ihalainen, JK, Hackney, AC, Valtonen, M, Nummela, A, Vaara, E, Häkkinen, K, Kyröläinen, H, and Taipale, RS. Hormonal contraceptive use does not affect strength, endurance, or body composition adaptations to combined strength and endurance training in women. J Strength Cond Res 35(2): 449-457, 2021-This study examined the effects of a 10-week period of high-intensity combined strength and endurance training on strength, endurance, body composition, and serum hormone concentrations in physically active women using hormonal contraceptives (HCs, n = 9) compared with those who had never used hormonal contraceptives (NHCs, n = 9). Training consisted of 2 strength training sessions and 2 high-intensity running interval sessions per week. Maximal bilateral isometric leg press (Isom), maximal bilateral dynamic leg press (one repetition maximum [1RM]), countermovement jump (CMJ), a 3,000-m running test (3,000 m), body composition, and serum hormone levels were measured before and after training between days 1-5 of each subject's menstrual cycle. Both groups increased 1RM and CMJ: HC = 13.2% (p < 0.001) and 9.6% (p < 0.05), and NHC = 8.3% (p < 0.01) and 8.5% (p < 0.001). Hormonal contraceptive improved 3,000 m by 3.5% (p < 0.05) and NHC by 1% (n.s.). Never used hormonal contraceptive increased lean mass by 2.1% (p < 0.001), whereas body fat percentage decreased from 23.9 ± 6.7 to 22.4 ± 6.0 (-6.0%, p < 0.05). No significant changes were observed in body composition in HC. No significant between-group differences were observed in any of the performance variables. Luteinizing hormone concentrations decreased significantly (p < 0.05) over 10 weeks in NHC, whereas other hormone levels remained statistically unaltered in both groups. It seems that the present training is equally appropriate for improving strength, endurance, and body composition in women using HC as those not using HC without disrupting hypothalamic-pituitary-gonadal axis function.

Cardiorespiratory response to exercise in endurance-trained premenopausal and postmenopausal females

PURPOSE

To assess the influence of different hormonal profiles on the cardiorespiratory response to exercise in endurance-trained females.

METHODS

Forty-seven eumenorrheic females, 38 low-dose monophasic oral contraceptive (OC) users and 13 postmenopausal women, all of them endurance-trained, participated in this study. A DXA scan, blood sample tests and a maximal aerobic test were performed under similar low-sex hormone levels: early follicular phase for the eumenorrheic females; withdrawal phase for the OC group and at any time for postmenopausal women. Cardiorespiratory variables were measured at resting and throughout the maximal aerobic test (ventilatory threshold 1, 2 and peak values). Heart rate (HR) was continuously monitored with a 12-lead ECG. Blood pressure (BP) was measured with an auscultatory method and a calibrated mercury sphygmomanometer. Expired gases were measured breath-by-breath with the gas analyser Jaeger Oxycon Pro.

RESULTS

One-way ANCOVA reported a lower peak HR in postmenopausal women (172.4 ± 11.7 bpm) than in eumenorrheic females (180.9 ± 10.6 bpm) (p = 0.024). In addition, postmenopausal women exhibited lower VO₂ (39.1 ± 4.9 ml/kg/min) compared to eumenorrheic females (45.1 ± 4.4 ml/kg/min) in ventilatory threshold 2 (p = 0.009). Nonetheless, respiratory variables did not show differences between groups at peak values. Finally, no differences between OC users and eumenorrheic females' cardiorespiratory response were observed in endurance-trained females.

CONCLUSIONS

Cardiorespiratory system is impaired in postmenopausal women due to physiological changes caused by age and sex hormones' decrement. Although these alterations appear not to be fully compensated by exercise, endurance training could effectively mitigate them. In addition, monophasic OC pills appear not to impact cardiorespiratory response to an incremental running test in endurance-trained females.

Effect of administration of monophasic oral contraceptive on the body composition and aerobic and anaerobic capacities of female athletes

AIM

To examine the effects of administration of monophasic oral contraceptive (OC) on the body composition and aerobic and anaerobic capacities of female athletes.

METHODS

Ten female athletes (23.0 ± 4.1 years old) participated in this study. All the subjects were examined during the menstrual cycle (early follicular [EF], middle luteal [ML]) and OC cycle (inactive OC, and active OC phases). After the menstrual cycle measurements, all the subjects began taking OC. The athletes tested using a body composition, circumferences, the lactate curve test, the maximal oxygen consumption test, and the Wingate test during all phases.

RESULTS

Waist circumference was lower during the OC cycle than menstrual cycle (P < 0.05), and the other circumferences of parts were not different during the menstrual or OC cycles. However, there were no differences in body composition before and after taking OC. The phase of the menstrual or OC cycle did not affect maximal oxygen consumption, heart rate max or power output at a blood lactate concentration of 2 and 4 mmol/L between the menstrual and OC cycle phases. Although, the peak blood lactate level after the Wingate test was higher during the OC cycle (inactive OC phase, 13.0 ± 2.4 mmol/L; active OC phase, 12.4 ± 3.0 mmol/L) than during the menstrual cycle (EF phase, 11.9 ± 2.1 mmol/L; ML phase, 11.4 ± 2.1 mmol/L; P < 0.05), the peak and average power in the Wingate test did not change during the menstrual and OC cycle phases.

CONCLUSION

Administration of monophasic OC did not affect the body composition or aerobic and anaerobic capacities of female athletes.

Impact of Menstrual Blood Loss and Oral Contraceptive Use on Oxygen-carrying Capacity

PURPOSE

The effect of menstrual blood loss on oxygen-carrying capacity remains equivocal. The purpose of this study was to determine the effect of menstrual blood loss on hemoglobin mass in young, healthy women.

METHODS

Twenty-one women (age, 23 ± 6 yr; height, 168 ± 7 cm; weight, 66.1 ± 12.6 kg) with regular menstrual cycles, either using (n = 10) or not using oral contraceptives, participated in the study. Hemoglobin mass was assessed using carbon monoxide rebreathing on three separate occasions over the course of one menstrual cycle.

RESULTS

Visits for women not using oral contraceptives were performed in the early follicular phase (3 ± 1 d after the onset of menses), late follicular phase (1 ± 1 d after the surge of luteinizing hormone in urine), and luteal phase (9 ± 1 d after the late follicular visit). Visits for women using oral contraceptives were performed in the early follicular phase (3 ± 1 d after the onset of menses), late follicular phase (15 ± 3 d after the onset of menses), and luteal phase (9 ± 2 d after the late follicular visit). Hemoglobin mass was not affected by menstrual cycle phase (early follicular, 618 ± 61; late follicular, 610 ± 65; luteal, 607 ± 68 g; P = 0.52). Interestingly, when normalized to weight, hemoglobin mass was 12% higher in women using oral contraceptives in comparison to nonusers (10.0 ± 1.2 vs 8.9 ± 1.2 g·kg, P < 0.05).

CONCLUSION

Menstrual blood loss had no measurable effect on hemoglobin mass in eumenorrheic women. However, oral contraceptive use resulted in a greater oxygen-carrying capacity, potentially leading to a greater maximal oxygen uptake.

Advancement in female sports medicine and preventive medicine

Sport plays a major role in maintaining and improving physical function and health of women from adolescence to sexual maturity, through to menopause and old age, and it also plays a key role in social productivity and medicine from the perspective of preventive medicine. However, in routine clinical practice, there are many gynecological problems that affect the condition and performance of female athletes due to a lack of appropriate medical intervention, such as neglect of amenorrhea and menstruation-related symptoms. In addition, the number of athletes aiming to return to competition post-partum has been increasing in recent years, but there is little medical data on the well-being of female athletes during pregnancy and the post-partum period. I previously conducted clinical research on three separate topics, with the aim of clarifying the current issues unique to female athletes, mainly in terms of conditioning and injury prevention. The goal was that clinical research was to examine the situation of athletes with and without disabilities and provide feedback from the survey results to athletes and coaches. This paper divides the clinical studies conducted to date into three topics that will be explored herein: (i) research on the female athlete triad (Triad); (ii) research on oral contraceptives/low-dose estrogen-progestin; and (iii) research on pregnancy and post-partum period.

The Effects of Oral Contraceptives on Exercise Performance in Women: A Systematic Review and Meta-analysis

BACKGROUND

Oral contraceptive pills (OCPs) are double agents, which downregulate endogenous concentrations of oestradiol and progesterone whilst simultaneously providing daily supplementation of exogenous oestrogen and progestin during the OCP-taking days. This altered hormonal milieu differs significantly from that of eumenorrheic women and might impact exercise performance, due to changes in ovarian hormone-mediated physiological processes.

OBJECTIVE

To explore the effects of OCPs on exercise performance in women and to provide evidence-based performance recommendations to users.

METHODS

This review complied with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A between-group analysis was performed, wherein performance of OCP users was compared with naturally menstruating women, and a within-group analysis was conducted, wherein performance during OCP consumption was compared with OCP withdrawal. For the between-group analysis, women were phase matched in two ways: (1) OCP withdrawal versus the early follicular phase of the menstrual cycle and (2) OCP consumption versus all phases of the menstrual cycle except for the early follicular phase. Study quality was assessed using a modified Downs and Black Checklist and a strategy based on the recommendations of the Grading of Recommendations Assessment Development and Evaluation working group. All meta-analyses were conducted within a Bayesian framework to facilitate probabilistic interpretations.

RESULTS

42 studies and 590 participants were included. Most studies (83%) were graded as moderate, low or very low quality, with 17% achieving high quality. For the between-group meta-analysis comparing OCP users with naturally menstruating women, posterior estimates of the pooled effect were used to calculate the probability of at least a small effect (d ≥ 0.2). Across the two between-group comparison methods, the probability of a small effect on performance favouring habitual OCP users was effectually zero (p < 0.001). In contrast, the probability of a small effect on performance favouring naturally menstruating women was moderate under comparison method (1) (d ≥ 0.2; p = 0.40) and small under comparison method (2) (d ≥ 0.2; p = 0.19). Relatively large between-study variance was identified for both between-group comparisons ([Formula: see text]0.5 = 0.16 [95% credible interval (CrI) 0.01-0.44] and [Formula: see text]0.5 = 0.22 [95% CrI 0.06-0.45]). For the within-group analysis comparing OCP consumption with withdrawal, posterior estimates of the pooled effect size identified almost zero probability of a small effect on performance in either direction (d ≥ 0.2; p ≤ 0.001).

CONCLUSIONS

OCP use might result in slightly inferior exercise performance on average when compared to naturally menstruating women, although any group-level effect is most likely to be trivial. Practically, as effects tended to be trivial and variable across studies, the current evidence does not warrant general guidance on OCP use compared with non-use. Therefore, when exercise performance is a priority, an individualised approach might be more appropriate. The analysis also indicated that exercise performance was consistent across the OCP cycle.

Changes in Self-Reported Physical Fitness, Performance, and Side Effects Across the Phases of the Menstrual Cycle Among Competitive Endurance Athletes

PURPOSE

To investigate changes in self-reported physical fitness, performance, and side effects across the menstrual cycle (MC) phases among competitive endurance athletes and to describe their knowledge and communication with coaches about the MC.

METHODS

The responses of 140 participants (older than 18 y) competing in biathlon or cross-country skiing at the (inter)national level were analyzed. Data were collected via an online questionnaire addressing participants' competitive level, training volume, MC history, physical fitness, and performance during the MC, MC-related side effects, and knowledge and communication with coaches about the MC and its effects on training and performance.

RESULTS

About 50% and 71% of participants reported improved and reduced fitness, respectively, during specific MC phases, while 42% and 49% reported improved and reduced performance, respectively. Most athletes reported their worst fitness (47%) and performance (30%) and the highest number of side effects during bleeding (P < .01; compared with all other phases). The phase following bleeding was considered the best phase for perceived fitness (24%, P < .01) and performance (18%, P < .01). Only 8% of participants reported having sufficient knowledge about the MC in relation to training, and 27% of participants communicated about it with their coach.

CONCLUSIONS

A high proportion of athletes perceived distinct changes in fitness, performance, and side effects across the MC phases, with their worst perceived fitness and performance during the bleeding phase. Because most athletes indicate a lack of knowledge about the MC's effect on training and performance and few communicate with coaches on the topic, the authors recommend that more time be devoted to educating athletes and coaches.

Oral Contraceptive Use Influences On-Kinetic Adaptations to Sprint Interval Training in Recreationally-Active Women

INTRODUCTION

Oral contraceptive (OC) use influences peak exercise responses to training, however, the influence of OC on central and peripheral adaptations to exercise training are unknown. This study investigated the influence of OC use on changes in time-to-fatigue, pulmonary oxygen uptake, cardiac output, and heart rate on-kinetics, as well as tissue saturation index to 4 weeks of sprint interval training in recreationally active women.

METHODS

Women taking an oral contraceptive (OC; n = 25) or experiencing natural menstrual cycles (MC; n = 22) completed an incremental exercise test to volitional exhaustion followed by a square-wave step-transition protocol to moderate (90% of power output at ventilatory threshold) and high intensity (Δ50% of power output at ventilatory threshold) exercise on two separate occasions. Time-to-fatigue, pulmonary oxygen uptake on-kinetics, cardiac output, and heart rate on-kinetics, and tissue saturation index responses were assessed prior to, and following 12 sessions of sprint interval training (10 min × 1 min efforts at 100-120% PPO in a 1:2 work:rest ratio) completed over 4 weeks.

RESULTS

Time-to-fatigue increased in both groups following training (p < 0.001), with no difference between groups. All cardiovascular on-kinetic parameters improved to the same extent following training in both groups. Greater improvements in pulmonary oxygen up-take kinetics were seen at both intensities in the MC group (p < 0.05 from pre-training) but were blunted in the OC group (p > 0.05 from pre-training). In contrast, changes in tissue saturation index were greater in the OC group at both intensities (p < 0.05); with the MC group showing no changes at either intensity.

DISCUSSION

Oral contraceptive use may reduce central adaptations to sprint interval training in women without influencing improvements in exercise performance - potentially due to greater peripheral adaptation. This may be due to the influence of exogenous oestradiol and progestogen on cardiovascular function and skeletal muscle blood flow. Further investigation into female-specific influences on training adaptation and exercise performance is warranted.

Cardiorespiratory Responses to Endurance Exercise Over the Menstrual Cycle and With Oral Contraceptive Use

Barba-Moreno, L, Cupeiro, R, Romero-Parra, N, Janse de Jonge, XA, and Peinado, AB. Cardiorespiratory Responses to Endurance Exercise Over the Menstrual Cycle and With Oral Contraceptive Use. J Strength Cond Res XX(X): 000-000, 2019-Female steroid hormone fluctuations during the menstrual cycle and exogenous hormones from oral contraceptives may have potential effects on exercise performance. The aim of this study was to investigate the effects of these fluctuations on cardiorespiratory responses during steady-state exercise in women. Twenty-three healthy endurance-trained women performed 40 minutes of running at 75% of their maximal aerobic speed during different phases of the menstrual cycle (n = 15; early follicular phase, midfollicular phase, and luteal phase) or oral contraceptive cycle (n = 8; hormonal phase and nonhormonal phase). Ventilatory parameters and heart rate (HR) were measured. Data were analyzed using a mixed linear model. For the eumenorrheic group, significantly higher oxygen uptake (p = 0.049) and percentage of maximum oxygen uptake (p = 0.035) were observed during the midfollicular phase compared with the early follicular. Heart rate (p = 0.004), oxygen ventilatory equivalent (p = 0.042), carbon dioxide ventilatory equivalent (p = 0.017), and tidal volume (p = 0.024) increased during luteal phase in comparison with midfollicular. In oral contraceptive users, ventilation (p = 0.030), breathing frequency (p = 0.018), oxygen ventilatory equivalent (p = 0.032), and carbon dioxide ventilatory equivalent (p = 0.001) increased during the hormonal phase. No significant differences were found for the rest of the parameters or phases. Both the eumenorrheic group and oral contraceptive group showed a significant increase in some ventilatory parameters during luteal and hormonal phases, respectively, suggesting lower cardiorespiratory efficiency. However, the lack of clinical meaningfulness of these differences and the nondifferences of other physiological variables, indicate that the menstrual cycle had a small impact on submaximal exercise in the current study.

Combined Oral Contraceptives Increase High-Sensitivity C-Reactive Protein but Not Haptoglobin in Female Athletes

BACKGROUND

No studies have examined the effects of oral hormonal contraception on chronic low-grade inflammation as assessed by stratified levels of high-sensitivity C-reactive protein (hsCRP) in athletes. We explored the impact of combined oral contraceptives (OCs) on serum hsCRP, haptoglobin, triglycerides and cholesterol in white female athletes.

METHODS

Italian sportswomen (n = 205; mean age 24 ± 5.3 years; body mass index 21 ± 2.2 kg m^-2; sport activity 8.7 ± 3.65 h week^-1) were analyzed according to OC use.

RESULTS

Progressive hsCRP levels were evaluated in OC users (n = 53) compared to non-OC users (n = 152). Levels of hsCRP from 3.0 to <10.0 mg L^-1 (at high risk of future cardiovascular events) were found in 26.4 % (14/53) of OC users and only in 2.6 % (4/153) of non-OC users (OR = 13.3, 95 % CI 4.14-42.6, P < 0.001). Risky hsCRP levels ≥1.0 mg L^-1 were found in 62.3 % of OC users versus 13.2 % non-OC users (OR = 10.9, 95 % CI 5.26-22.5, P < 0.001). Protective hsCRP levels (<0.5 mg L^-1) were found in 17.0 % of OC users and in 64.5 % of non-OC users (OR = 0.11, 95 % CI 0.05-0.25, P < 0.001). OC use increased serum triglycerides (P < 0.001), total cholesterol (P = 0.027) and HDL cholesterol (P = 0.018), whereas haptoglobin was unaffected. Hours of exercise week^-1 had a mild inverse association with hsCRP (P = 0.048) in non-OC users only.

CONCLUSIONS

OC use markedly elevated chronic low-grade inflammation in athletes, which could predispose to a higher inflammatory response to physical stress and elevate cardiovascular risk. Physical activity without OC use seemed to favor low hsCRP. Further research is needed to extend our results and to elucidate the potential effects on athletic performance of chronically elevated hsCRP. Our findings would be useful for sport physicians interpreting blood tests in athletes.

Sex and nitric oxide bioavailability interact to modulate interstitial Po2 in healthy rat skeletal muscle

Premenopausal women express reduced blood pressure and risk of cardiovascular disease relative to age-matched men. This purportedly relates to elevated estrogen levels increasing nitric oxide synthase (NOS) activity and NO-mediated vasorelaxation. We tested the hypotheses that female rat skeletal muscle would: 1) evince a higher O₂ delivery-to-utilization ratio (Q̇o₂/V̇o₂) during contractions; and 2) express greater modulation of Q̇o₂/V̇o₂ with changes to NO bioavailability compared with male rats. The spinotrapezius muscle of Sprague-Dawley rats (females = 8, males = 8) was surgically exposed and electrically-stimulated (180 s, 1 Hz, 6 V). OxyphorG4 was injected into the muscle and phosphorescence quenching employed to determine the temporal profile of interstitial Po₂ (Po_2is, determined by Q̇o₂/V̇o₂). This was performed under three conditions: control (CON), 300 µM sodium nitroprusside (SNP; NO donor), and 1.5 mM N^ω-nitro-l-arginine methyl ester (l-NAME; NOS blockade) superfusion. No sex differences were found for the Po_2is kinetics parameters in CON or l-NAME ( P > 0.05), but females elicited a lower baseline following SNP (males 42 ± 3 vs. females 36 ± 2 mmHg, P < 0.05). Females had a lower ΔPo_2is during contractions following SNP (males 22 ± 3 vs. females 17 ± 2 mmHg, P < 0.05), but there were no sex differences for the temporal response to contractions ( P > 0.05). The total NO effect (SNP minus l-NAME) on Po_2is was not different between sexes. However, the spread across both conditions was shifted to a lower absolute range for females (reduced SNP baseline and greater reduction following l-NAME). These data support that females have a greater reliance on basal NO bioavailability and males have a greater responsiveness to exogenous NO and less responsiveness to reduced endogenous NO. NEW & NOTEWORTHY Interstitial Po₂ (Po_2is; determined by O₂ delivery-to-utilization matching) plays an important role for O₂ flux into skeletal muscle. We show that both sexes regulate Po_2is at similar levels at rest and during skeletal muscle contractions. However, modulating NO bioavailability exposes sex differences in this regulation with females potentially having a greater reliance on basal NO bioavailability and males having a greater responsiveness to exogenous NO and less responsiveness to reduced endogenous NO.

Oral Contraceptive Use Dampens Physiological Adaptations to Sprint Interval Training

PURPOSE

Oral contraceptive (OC) use reduces peak aerobic capacity (V˙O2peak); however, whether it also influences adaptations to training has yet to be determined. This study aimed to examine the influence of OC use on peak performance (peak power output [PPO]) and physiological adaptations (V˙O2peak and peak cardiac output [Q˙peak]) after sprint interval training (SIT) in recreationally active women.

METHODS

Women taking an OC (n = 25) or experiencing natural regular menstrual cycles (MC; n = 16) completed an incremental exercise test to assess V˙O2peak, PPO, and Q˙peak before, immediately after, and 4 wk after 12 sessions of SIT. The SIT consisted ten 1-min efforts at 100% to 120% PPO in a 1:2 work-rest ratio.

RESULTS

Though V˙O2peak increased in both groups after SIT (both P < 0.001), the MC group showed greater improvement (OC, +8.5%; MC, +13.0%; P = 0.010). Similarly, Q˙peak increased in both groups, with greater improvement in the MC group (OC, +4.0%; MC, +16.1%; P = 0.013). PPO increased in both groups (OC, +13.1%; MC, +13.8%; NS). All parameters decreased 4 wk after SIT cessation, but remained elevated from pretraining levels; the OC group showed more sustained training effects in V˙O2peak (OC, -4.0%; MC, -7.7%; P = 0.010).

CONCLUSION

SIT improved peak exercise responses in recreationally active women. However, OC use dampened V˙O2peak and Q˙peak adaptation. A follow-up period indicated that OC users had spared V˙O2peak adaptations, suggesting that OC use may influence the time course of physiological training adaptations. Therefore, OC use should be verified, controlled for, and considered when interpreting physiological adaptations to exercise training in women.

The effect of oral contraceptive use on salivary testosterone concentrations and athlete performance during international field hockey matches

OBJECTIVES

To investigate the effect of oral contraceptive (OC) use on salivary testosterone (sal-T) concentrations and performance-related statistics in international field hockey matches.

DESIGN

A cohort observational study with repeated measures.

METHODS

Twenty-three elite female athletes were monitored across four international field hockey matches over a nine-day period. Salivary T was assessed 45min before each match and several match performance statistics were collated; load (i.e. ratings of perceived exertion×playing time), video-derived positive actions (PA) and negative actions (NA), plus coach and player ratings of performance. The sal-T and match performance profiles of OC (n=7) and Non-OC (n=16) players were compared and predictive relationships tested.

RESULTS

Pre-match sal-T concentrations were 35% higher in the Non-OC than the OC group (p=0.001), representing a large effect size (ES) difference of 0.96. The OC and Non-OC groups did not differ on any performance statistic (p≥0.348) with ES differences from -0.22 to 0.11. Salivary T was positively related to the number of PA during match play (p=0.017). Additional linkage between sal-T and NA emerged, but with opposing slopes (p=0.008) in the OC (B=-1.783, p=0.030) and Non-OC (B=0.692, p=0.127) groups.

CONCLUSIONS

OC usage by elite women athletes was accompanied by lower sal-T concentrations, but the performance outputs of the OC and Non-OC groups were similar. This suggests that the T differences had no impact on match performance. On an individual (population-averaged) level, sal-T was associated with PA and NA during these matches, though the response curves predicting NA differed for OC and Non-OC athletes.

Oxidative Stress in Female Athletes Using Combined Oral Contraceptives

Background

Oxidative stress in female athletes is understudied. We investigated oxidative stress in sportswomen of different disciplines according to combined oral contraceptive (OC) use and lifestyle/alimentary habits.

Methods

Italian sportswomen (n = 144; mean age 23.4 ± 4.2 years; body mass index 21.2 ± 2.2 kg m⁻²; sport activity 9.2 ± 4.1 h week⁻¹) were analyzed; 48 % were volleyball players, 12.5 % soccer players, 10.4 % track-and-field sports, and followed by other disciplines’ athletes. Oxidative stress was evaluated by free oxygen radical test (FORT) assessing blood hydroperoxides and free oxygen radical defense (FORD) assay evaluating antioxidant capacity in OC users (n = 42) compared to non-OC users.

Results

Elevated oxidative stress levels (≥310 FORT units) were found in 92.9 % of OC users and in 23.5 % of non-OC users (crude OR = 42, 95 % CI 12–149, p < 0.001; adjusted OR = 60, 95 % CI 11–322, p < 0.001). Continuous values of hydroperoxides were twofold higher in OC users versus non-OC users (median 484 versus 270 FORT units, p < 0.001) and were inversely related to FORD units in OC users (p = 0.01). Hydroperoxides were not associated with weekly hours of exercise. In OC users, lifestyle/alimentary habits were not correlated to hydroperoxides. In non-OC users only, hydroperoxide values were positively correlated with weight and BMI and inversely correlated with chocolate and fish consumption.

Conclusions

The markedly elevated oxidative stress we revealed in OC-user athletes could be detrimental to physical activity and elevate cardiovascular risk (as thromboembolism). Further research is needed to extend our results, to clarify the biochemical pathways leading to increased hydroperoxides (mainly lipid peroxides) and reduced antioxidant defense, and to elucidate the potential effects on athletic performance. OC use should be considered when developing gender-focused strategies against oxidative stress.

Exercise, Training, and the Hypothalamic-Pituitary-Gonadal Axis in Men and Women

The hypothalamic-pituitary-gonadal (HPG) axis is essential for adequate responses to exercise and training both acutely and chronically. Both testosterone and estrogen play leading roles in neuromuscular adaptation to exercise in males and females. The purpose of this chapter is to illustrate the physiological and pathological changes that occur in the HPG axis secondary to exercise and training. In males, testosterone increases with acute bouts of exercise, but long-term effects are less clear, with evidence of lower testosterone in endurance athletes. Restricted energy availability may negatively affect hormone levels in male endurance athletes, but data regarding low energy availability and its impact on the HPG axis are limited in male athletes. Conversely, in females there is significant evidence that decreased energy availability inhibits the HPG axis, leading to menstrual irregularities and lower bone density. Hormonal changes secondary to acute bouts of exercise are more challenging to interpret in females due to menstrual variability, which traditionally has not been taken into account in many studies. However, some evidence supports an increase in testosterone and estradiol with acute exercise. More work is needed to elucidate the relationships among energy availability, basal hormonal fluctuations, and exercise, and their collective effects on the HPG axis.

Maximal fat oxidation, but not aerobic capacity, is affected by oral contraceptive use in young healthy women

PURPOSE

Synthetic ovarian hormones contained in oral contraceptives (OC) may alter the aerobic capacity and lipid metabolism in oral contraceptive users (OC+) compared with non-users (OC-). The aim of this study was thus to investigate the differences between OC- and OC+ (1) in cardiorespiratory parameters at the anaerobic threshold (AT) and at the maximal aerobic capacity and (2) in the exercise intensity (Lipoxmax) at which lipid oxidation rate is maximal (MLOR).

METHODS

Twenty-one healthy untrained women (22.0 ± 0.6 years old) who took OC (OC+; low-dose monophasic OC, n = 11) or not (OC-; n = 10) performed two experimental exercise sessions. In the first one, cardiorespiratory parameters at the AT and at the maximal aerobic capacity were assessed during a maximal incremental exercise session. In the second one, Lipoxmax and MLOR were measured during a submaximal incremental exercise session.

RESULTS

No significant difference was observed in cardiorespiratory parameters at the AT and at the maximal aerobic capacity between OC+ and OC- women. OC+ women showed higher MLOR (7.6 ± 1.9 vs 4.6 ± 1.0 mg min(-1) kg FFM(-1); p < 0.01) that was elicited by higher Lipoxmax (45.2 ± 5.2 vs 36.2 ± 4.1 % of VO2max; p < 0.001) compared to OC- women.

CONCLUSIONS

OC+ and OC- women did not differ in cardiorespiratory parameters at the AT and at the maximal aerobic capacity. However, OC+ women show higher MLOR and Lipoxmax compared with OC- women. The hormonal status appears to be an important MLOR and Lipoxmax determinant in untrained women.

Exercise per se masks oral contraceptive-induced postprandial lipid mobilization

Because of their hormonal content, oral contraceptives may alter lipolytic activity under resting or exercise conditions in women. The aim of the present study was to compare lipid mobilization in a postprandial state at rest and during exercise in oral contraceptive users (OC+) versus nonusers (OC–). The metabolic (glucose, glycerol, free fatty acids) and hormonal (insulin, atrial natriuretic peptide (ANP), growth hormone, insulin-like growth factor-1 (IGF-1), and catecholamines) concentrations were determined in 11 OC+ (monophasic low-dose oral contraceptives) and 10 OC– during a resting and an exercise session (45 min at 65% maximal oxygen consumption). Results were expressed as plasma concentrations and area under the concentration versus time curve values. ANP concentrations were higher in OC+ compared with OC– women at baseline (p = 0.04). Plasma concentrations of glycerol (p = 0.04), free fatty acids (p = 0.04), ANP (p = 0.02), and noradrenaline (p = 0.04) were higher in OC+ compared with OC– when both sessions were pooled. The plasma growth hormone, IGF-1, and adrenaline concentrations were not significantly different between the 2 groups. When the effect of exercise was isolated to overcome food intake and daytime variations (exercise per se using the area under the curve), no difference was observed between groups for all metabolic and hormonal variables. Overall, oral contraceptives increased lipid mobilization in the postprandial state, but this effect was blunted when lipolytic activity was stimulated by exercise per se. Oral contraceptive-induced greater lipolytic mobilization could be partly explained by greater ANP levels in OC users.

Running longer, running stronger: a brief review of endurance exercise and oestrogen

Athletic performance in endurance exercise is determined by an interplay among many physiological factors. Body fluid regulation, influenced by both hormonal and osmotic stimuli, is particularly important for maximising performance in endurance sports, as dehydration markedly decreases endurance. Oestrogen has a broad range of effects on the regulation of body fluid balance, as well as on aerobic capacity, metabolism, and other factors that impact endurance exercise performance, yet the role of oestrogen in endurance exercise performance has not been thoroughly examined. This review discusses the effects of oestrogen on compensatory hormonal and behavioural responses to dehydration, such as renin-angiotensin-aldosterone system activation and thirst, that restore body fluid balance and thereby affect exercise performance. Oestrogen-mediated effects and their potential consequences for endurance performance are also evaluated in the context of thermoregulation and aerobic capacity, as well as substrate utilisation during exercise. In addressing the role of oestrogen in endurance exercise, this review will examine human and animal models of endurance exercise and discuss similarities, differences, and limitations. Our aim is to integrate research from neuroscience, physiology, and exercise science to advance understanding of how oestrogen may impact exercise. Such understanding will have particularly important implications for female endurance athletes experiencing the hormonal fluctuations that occur during the reproductive cycle.

Oral contraceptives do not affect muscle strength and hop performance in active women

OBJECTIVE

The primary aim of this study was to compare muscle strength in the upper and lower limb, as well as hop performance during oral contraceptive (OC) use with non-OC use in the same woman. A secondary aim was to compare muscle strength and hop performance within 3 specific phases of an OC cycle, as well as during a menstrual cycle of the corresponding cycle days (non-OC cycle).

DESIGN

Crossover.

SETTING

Research laboratory.

PARTICIPANTS

Seventeen moderate to highly recreationally active women participated in the study.

INTERVENTION

Observational study with no intervention.

MAIN OUTCOME MEASURES

Maximal isokinetic muscle strength of knee extensors, isometric handgrip strength, and 1-leg hop test for distance were measured during 1 OC cycle and 1 non-OC cycle at 3 specific phases, respectively, using a crossover design.

RESULTS

No significant differences were found in terms of muscle strength and hop performance between the OC cycle and the non-OC cycle. Furthermore, no significant difference in muscle strength and hop performance could be demonstrated within the OC cycle or within the phases of the menstrual cycle except from maximal isokinetic muscle strength in the knee extensors detected between the early follicular phase and the luteal phase.

CONCLUSIONS

We found no support for any significant influence of OC use on muscle strength and hop performance in healthy moderately active women.

Oral contraceptive cycle phase does not affect 200-m swim time trial performance

The purpose of this study was to examine whether swimming performance was affected by acute hormonal fluctuation within a monophasic oral contraceptive (OC) cycle. Six competitive swimmers and water polo players completed a 200-m time trial at 3 time points of a single OC cycle: during the consumption phase (CONS), early (WITH1), and late in the withdrawal phase (WITH2). Split times and stroke rate were recorded during the time trial, and heart rate, blood lactate, glucose, and pH were measured after each performance test. Resting endogenous serum estradiol and progesterone concentrations were also assessed. No significant differences were observed between phases for body composition, 200-m swim time, mean stroke rate, peak heart rate, or blood glucose (p > 0.05). The mean peak blood lactate was significantly lower during WITH2 (9.9 ± 3.0 mmol·L(-1)) compared with that of CONS (12.5 ± 3.0 mmol·L(-1)) and mean pH higher during WITH2 (7.183 ± 0.111) compared with that of CONS (7.144 ± 0.092). Serum estradiol levels were significantly greater during WITH2 compared with that during WITH1 and CONS, but there was no difference in serum progesterone levels. These results demonstrate that for monophasic OC users, cycle phase does not impact the 200-m swimming performance. There was a reduction in blood lactate and an increase in pH during the withdrawal phase, possibly because of an increase in fluid retention, plasma volume, and cellular alkalosis. Therefore, female 200-m swimmers taking a monophasic OC need not be concerned by the phase of their cycle with regard to competition and optimizing performance. However, coaches and scientists should exercise caution when interpreting blood lactate results obtained from swimming tests and consider controlling for cycle phase for athletes taking an OC.

Exploratory study on oxygen consumption on-kinetics during treadmill walking in women with systemic lupus erythematosus

OBJECTIVE

To determine whether oxygen consumption (V o(2)) on-kinetics differed between groups of women with systemic lupus erythematosus (SLE) and sedentary but otherwise healthy controls.

DESIGN

Exploratory case-control study.

SETTING

Medical school exercise physiology laboratory.

PARTICIPANTS

Convenience samples of women with SLE (n=12) and sedentary but otherwise healthy controls (n=10).

INTERVENTION

None.

MAIN OUTCOME MEASURES

V o(2) on-kinetics indices including time to steady state, rate constant, mean response time (MRT), transition constant, and oxygen deficit measured during bouts of treadmill walking at intensities of 3 and 5 metabolic equivalents (METs).

RESULTS

Time to steady state and oxygen deficit were increased and rate constant was decreased in the women with SLE compared with controls. At the 5-MET energy demand, the transition constant was lower and MRT was longer in the women with SLE than in controls. For a similar relative energy expenditure that was slightly lower than the anaerobic threshold, the transition constant was higher in controls than in women with SLE.

CONCLUSION

V o(2) on-kinetics was prolonged in women with SLE. The prolongation was concomitant with an increase in oxygen deficit and may underlie performance fatigability in women with SLE.

Effect of low-dose combined oral contraceptive on aerobic capacity and anaerobic threshold level in active and sedentary young women

BACKGROUND

The purpose of this study was to evaluate the effect of long-term use of oral contraceptives (OC) containing 0.20 mg of ethinylestradiol (EE) combined with 0.15 mg of gestodene (GEST) on the peak aerobic capacity and at the anaerobic threshold (AT) level in active and sedentary young women.

STUDY DESIGN

Eighty-eight women (23+/-2.1 years old) were divided into four groups - active-OC (G1), active-NOC (G2), sedentary-OC (G3) and sedentary-NOC (G4) - and were submitted to a continuous ergospirometric incremental test on a cycloergometer with 20 to 25 W min(-1) increments. Data were analyzed by two-way ANOVA with Tukey post hoc test. Level of significance was set at 5%.

RESULTS

The OC use effect for the variables relative and absolute oxygen uptake VO(2) mL kg-(1) min(-1); VO(2), L min(-1), respectively), carbon dioxide output (VCO(2), L min(-1)), ventilation (VE, L min(-1)), heart rate (HR, bpm), respiratory exchange ratio (RER) and power output (W) data, as well as the interaction between OC use and exercise effect on the peak of test and at the AT level did not differ significantly between the active groups (G1 and G2) and the sedentary groups (G3 and G4). As to the exercise effect, for all variables studied, it was noted that the active groups presented higher values for the variables VO(2), VCO(2), VE and power output (p<.05) than the sedentary groups. The RER and HR were similar (p>.05) at the peak and at the AT level between G1 vs. G3 and G2 vs. G4.

CONCLUSIONS

Long-term use of OC containing EE 0.20 mg plus GEST 0.15 mg does not affect aerobic capacity at the peak and at the AT level of exercise tests.

Athletic performance and the oral contraceptive

Some reports suggest variation in physiological responses and athletic performance, for female athletes at specific phases of the menstrual cycle. However, inconsistent findings are common due to the inappropriate verification of menstrual cycle phase, small subject numbers, high intra- and interindividual variability in estrogen and progesterone concentration, and the pulsatile secretion of these hormones. Therefore, the oral contraceptive (OC) cycle may provide a more stable environment in which to evaluate the acute effect of reproductive hormones on physiological variables and exercise performance. To date, most of the OC research has compared differences between OC use and nonuse, and few researchers have examined within-cycle effects of the OC. It is also apparent that OC use is becoming far more prevalent in athletes; hence the effect of the different exogenous and endogenous hormonal profiles on athletic performance should be investigated. Research to date identifies potential for variation in aerobic performance, anaerobic capacity, anaerobic power and reactive strength throughout an OC cycle. The purpose of this review is to present and evaluate the current literature on the physiology of exercise and athletic performance during the OC cycle.

The influence of oral contraceptives on athletic performance in female athletes

It is now estimated that the prevalence of oral contraceptive use in athletic women matches that of women in the general population. The oral contraceptive pill (OCP) reduces cycle-length variability and provides a consistent 28-day cycle by controlling concentrations of endogenous sex hormones. The OCP is administered in three different forms that differ widely in chemical constitution and concomitant effects on the human body. As fluctuation in sex steroids are believed to be a possible causal factor in performance and exercise capacity, it is imperative to understand the effect of administering the various types of OCP on women. However, the research into oral contraceptives and exercise performance is not consistent. The type of OCP administered (monophasic, biphasic or triphasic), as well as the type and dose of estrogen and progestogen within, will have varying effects on exercise. To date, research in the area of oral contraceptives and exercise capacity is sparse and much has been plagued by poor research design, methodology and small sample size. It is clear from the research to date that more randomised clinical trials are urgently required to assess the array of OCP formulations currently available to women and their concomitant effect on health and exercise capacity. Therefore, the purpose of this article is to critically appraise the literature to date and to provide a current review of the physiological scientific knowledge base in relation to the OCP and exercise performance. In addition, methodological control, design and conduct will be considered with future areas of research highlighted.

Androgenicity of the progestin in oral contraceptives does not affect maximal leg strength

PURPOSE

This study was conducted to examine androgenicity of the progestin in oral contraceptive pills and its effect on maximal leg strength in females.

METHODS

Twelve participants who were using a monophasic pill containing 30 microg ethinylestradiol plus either 150 microg levonorgestrel (LEV) or 250 microg norgestimate (NOR) for at least the last 6 months were recruited (mean+/-SEM; LEV: age, 19.8+/-0.3 years; stature, 1.67+/-0.17 m; mass, 65.9+/-1.9 kg; NOR: age, 20.6+/-0.2 years; stature, 1.65+/-0.17 m; mass, 64.6+/-2.4 kg). Three maximal isokinetic extension and flexion tests were performed on three occasions (Days 3-6, 11-14 and 18-21 of the pill cycle) to assess peak extension and peak flexion torque (in Newton meters).

RESULTS

No significant (p>.05) differences were found in the LEV and NOR groups in peak extension torque (F=0.719; p=.416) or peak flexion torque (F=0.291, p=.601) throughout the pill cycle and between groups.

CONCLUSION

In this small study, the androgenicity of the progestin in the contraceptive pill had no significant association with maximal strength in these female athletes.

No correlation between circulating ACE activity and $$ {\user2{V}}{\mathbf{O}}_{{{\mathbf{2}}_{{{\mathbf{max}}}} }} $$ or mechanical efficiency in women

The insertion (I) variant of the angiotensin-1 converting enzyme (ACE) I/D genetic polymorphism is associated with lower circulating and tissue ACE activity. Some studies have also suggested associations of ACE I/D genotype with endurance phenotypes. This study assessed the relationships between circulating ACE activity, ACE I/D genotype, mechanical efficiency and the maximal rate of oxygen uptake in sedentary individuals. Sixty-two untrained women were tested for mechanical efficiency during submaximal cycle ergometry (delta and gross efficiencies during exercise between 40 and 80 W) and the maximal rate of oxygen uptake during incremental treadmill running. Respiratory variables were measured using indirect calorimetry. Venous blood was obtained for direct assay of circulating ACE activity, allowing for the assessment of correlations between two continuous variables, rather than a categorical analysis of endurance phenotype by genotype alone. ACE I/D genotype was also determined, and was strongly associated with circulating ACE activity (P < 0.0005). Neither circulating ACE activity (27.4 +/- 8.4 nM His-Leu-ml(-1)) nor ACE genotype showed a statistically significant association with any of the endurance phenotypes measured. The weak correlations observed included r = -0.122 (P = 0.229) for the relationship between delta efficiency (23.9 +/- 2.5%) and circulating ACE activity and r = 0.134 (P > 0.6) for the relationship between maximal aerobic power (149.1 +/- 22.9 ml kg(-2/3) min(-1)) and circulating ACE activity. The data do not support a role for systemic ACE activity in the regulation of endurance performance in sedentary individuals, extending this observation to a large female cohort.

The menstrual cycle and sport performance

The female sex steroid hormones estrogen and progesterone have potential effects on exercise capacity and performance through numerous mechanisms, such as substrate metabolism, cardiorespiratory function, thermoregulation, psychologic factors, and injuries. Consequently, hormone level changes may theoretically lead to either improved or decreased performance at various times throughout the menstrual cycle. Numerous methodological issues and a paucity of studies have precluded evidence-based conclusions in almost every area of research in this field. In addition, there appears to be a great degree of inter- and intraindividual variability in these hormonal responses. Using oral contraceptives may be advantageous for female athletes who are negatively affected by their menstrual cycle, as they may provide a stable yet controllable hormonal milieu for training and competition.

Medication and supplement use by athletes

Athletes are affected in various ways by medications and supplements. Physicians caring for athletes need to be aware of medicines that athletes are taking and how they may interact with performance, exercise, environment, and other medicines. Athletes may attempt to gain a performance advantage with the use of a variety of dietary supplements and performance enhancers. Physicians must be knowledgeable of these so that athletes are properly educated about potential benefits and risks and physical effects. This article first reviews common medicines that athletes use and their potential efficacy and interactions with exercise and environment, then reviews dietary supplements and the data on their efficacy for performance enhancement. Finally, current and future doping issues are discussed.