Effects of Training on Running Cost and Aerobic Capacity in Individuals with Obesity.

This study investigated running cost (CRun), peak oxygen consumption (V̇ O2peak), and ventilatory threshold (VT1) responses to exercise programs for individuals with obesity. Ninety-four individuals (38.2±7.7 years; 33.4±2.9 kg/m²) were assigned into strength (n=24), endurance (n=26), combined (n=22), and physical activity (control, n=22) groups for 22 weeks, plus diet recommendation. The V̇ O2peak, VT1, and CRun were assessed through a maximal incremental step test. The change of V̇ O2peak in combined (9.9%) differed from the other groups, with lower values in women than men (0.7% vs. 6.2%). The VT1 change in combined (16.4%) differed from the strength (4.9%) and physical activity (1.2%) groups, with the change in endurance (12.7%) also being higher than the physical activity group. Only men in the combined group increased absolute V̇ O2peak, while both sexes increased VT1 in the endurance and combined groups. No effects for groups and sex were significant for CRun in moderate (VT1) running zones, despite CRun changes in VT1 zones correlated with the alterations of V̇ O2peak and VT1 (r²=0.29-0.59). Therefore, moderate aerobic exercise stimulus is suitable for VT1 improvement in individuals with obesity, with the increase in CRun associated to the chances of increasing V̇ O2peak in men and when combining strength with aerobic exercises.

The moderating role of macronutrient intake in relation to body composition and genotoxicity: A study with gym users.

In a cross-sectional study of gymnasium users (both sexes, ages = 41.9 ± 14.8 years), we examined the moderating role of macronutrient intake in relation to body composition and genotoxicity. A questionnaire was administered to evaluate characteristics of the participants. To assess macronutrient consumption, we used 24-h food recalls on three non-consecutive days. Body composition (body fat percentage and muscle mass) was evaluated with a bioimpedance scale. Genotoxicity was assessed with the buccal micronucleus cytome assay. Multiple linear regression models were applied, adjusting for age; sex; tobacco and alcohol consumption; and (with regard to exercise habits) frequency, training time, intensity, and types. Micronucleus frequency was directly associated with body fat and inversely associated with muscle mass. Our study shows that carbohydrate and fat intakes affect body fat percentage and micronucleus frequency in gymnasium users.

The real bacterial filtration efficiency to evaluate the effective protection of facemasks used for the prevention of respiratory diseases.

The real protection offered by facemasks to control the transmission of respiratory viruses is still undetermined. Most of the manufacturing regulations, as well as scientific studies, have focused on studying the filtration capacity of the fabrics from which they are made, ignoring the air that escapes through the facial misalignments, and which depends on the respiratory frequencies and volumes. The objective of this work was to define a Real Bacterial Filtration Efficiency for each type of facemask, considering the bacterial filtration efficiency of the manufacturers and the air that passes through them. Nine different facemasks were tested on a mannequin with three gas analyzers (measuring inlet, outlet, and leak volumes) inside a polymethylmethacrylate box. In addition, the differential pressure was measured to determine the resistance offered by the facemasks during the inhalation and exhalation processes. Air was introduced with a manual syringe for 180 s simulating inhalations and exhalations at rest, light, moderate and vigorous activities (10, 60, 80 and 120 L/min, respectively). Statistical analysis showed that practically half of the air entering to the system is not filtered by the facemasks in all intensities (p < 0.001, ηp2 = 0.971). They also showed that the hygienic facemasks filter more than 70% of the air, and their filtration does not depend on the simulated intensity, while the rest of the facemasks show an evidently different response, influenced by the amount of air mobilized. Therefore, the Real Bacterial Filtration Efficiency can be calculated as a modulation of the Bacterial Filtration Efficiencies that depends on the type of facemask. The real filtration capacity of the facemasks has been overestimated during last years since the filtration of the fabrics is not the real filtration when the facemask is worn.

Effect of Menstrual Cycle Phase on the Recovery Process of High-Intensity Interval Exercise-A Cross-Sectional Observational Study.

Although the study of the menstrual cycle influence on endurance exercise has recently increased, there is a lack of literature studying its influence on females' cardiorespiratory recovery. Thus, the aim of the present work was to assess menstrual cycle influence on post-exercise recovery following a high intensity interval exercise in trained females. Thirteen eumenorrheic endurance-trained females performed an interval running protocol in three menstrual cycle phases: early follicular phase (EFP), late follicular phase (LFP), and mid-luteal phase (MLP). The protocol consisted of 8 × 3-min bouts at 85% of their maximal aerobic speed (vVO2peak) with a 90-s rest between bouts and a final 5-min active recovery at 30% vVO2peak. All variables were averaged every 15 s, obtaining 19 moments during recovery (time factor). To analyze the effects of the menstrual cycle on the final active cardiorespiratory recovery, an ANOVA for repeated measures was performed. ANOVA showed an effect on menstrual cycle phase on ventilation (EFP: 1.27 ± 0.35; LFP: 1.19 ± 0.36; MLP: 1.27 ± 0.37), breathing frequency (EFP: 35.14 ± 7.14; LFP: 36.32 ± 7.11; MLP: 37.62 ± 7.23), and carbon dioxide production (EFP: 1120.46 ± 137.62; LFP: 1079.50 ± 129.57; MLP: 1148.78 ± 107.91). Regarding the interaction results (phase x time), ventilation is higher at many of the recovery times during the MLP, with less frequent differences between EFP and LFP (F = 1.586; p = 0.019), while breathing reserve is lower at many of the recovery times during MLP, with less time differences between EFP and LFP (F = 1.643; p = 0.013). It seems that the menstrual cycle affects post-exercise recovery specially during the MLP, rising ventilation and lowering breathing reserve, giving rise to an impaired ventilatory efficiency.

Serum iron availability, but not iron stores, is lower in naturally menstruating than in oral contraceptive athletes.

This study measured serum markers of iron status in naturally menstruating and oral contraceptive (OC) athletes during the main hormonal milieus of these two profiles to identify potential differences confounding the diagnosis of iron deficiency in female athletes. Resting blood samples were collected from 36 naturally menstruating athletes during the early-follicular phase (EFP), mid- late-follicular phase (MLFP) and mid-luteal phase (MLP) of the menstrual cycle. Simultaneously, blood samples were collected from 24 OC athletes during the withdrawal and active-pill phase of the OC cycle. Serum iron, ferritin, transferrin, transferrin saturation (TSAT), C-reactive protein (CRP), interleukin-6 and sex hormones were analyzed. Naturally menstruating athletes showed lower levels of TSAT, iron and transferrin than OC athletes when comparing the bleeding phase of both profiles (p<0.05) as well as when comparing all analyzed phases of the menstrual cycle to the active pill phase of the OC cycle (p<0.05). Interestingly, only lower transferrin was found during MLFP and MLP compared to the withdrawal phase of the OC cycle (p>0.05), with all other iron markers showing no differences (p>0.05). Intracycle variations were also found within both types of cycle, presenting reduced TSAT and iron during menstrual bleeding phases (p<0.05). In conclusion, in OC athletes, serum iron availability, but not serum ferritin, seems higher than in naturally menstruating ones. However, such differences are lost when comparing the MLFP and MLP of the menstrual cycle with the withdrawal phase of the OC cycle. This should be considered in the assessment of iron status in female athletes.Highlights Naturally menstruating athletes present lower TSAT, iron and transferrin in all analyzed phases of the menstrual cycle compared to OC athletes during their active pill phase. However, both the mid-late follicular and mid-luteal phases of the menstrual cycle do not differ from the withdrawal phase of the oral contraceptive cycle.Intracycle variations are found for TSAT and iron in both naturally menstruating and oral contraceptive athletes, which are mainly driven by a reduction in TSAT and iron during menstrual bleeding phases.As serum iron availability changes significantly as a function of the athlete's hormonal status, it should be considered in the assessment of the athlete's iron status as well as standardise the phase of the menstrual cycle in which to assess iron markers to avoid misdiagnosis or misleading results.In contrast, the assessment of iron stores through serum ferritin is substantially stable and the athlete's hormonal status does not seem to be of relevance for this purpose.

Validity and reliability of the International fItness scale (IFIS) in preschool children.

Objectives: Examine the validity and reliability of parent-reported International FItness Scale (IFIS) in preschoolers. Method: A cross-sectional study of 3051 Spanish preschoolers (3-5 years). Fitness was measured by PREFIT battery and reported by parents using an adapted version of the IFIS. Waist circumference was evaluated, and the waist-to-height ratio (WHtR) was calculated. Seventy-six parents of randomly selected schoolchildren completed the IFIS twice for a reliability assessment. Results: ANCOVA, adjusted for sex, age and WHtR, showed that preschoolers who were scored by their parents as having average-to-very good fitness had better levels of measured physical fitness than those preschoolers who were classified as having "very poor/poor" fitness levels (18.1laps to 22.1laps vs 15.6laps for cardiorespiratory fitness; 6.6 kg to 7.5 kg vs 5.3 kg for muscular fitness-handgrip-; 71.7 cm to 76.4 cm vs 62.0 cm for muscular fitness-standing long jump-; 17.2s to 16.2s vs 18.2s for speed/agility; and 11.2s to 15.6s vs 8.7s for balance; p < 0.001). The weighted kappa for concordance between parent-reported fitness levels and objective assessment was poor (κ ≤ 0.18 for all fitness measures). Overall, the mean values of the abdominal adiposity indicators were significantly lower in high-level fitness categories reported by parents than in low-level fitness categories (p < 0.05). The test-retest reliability ranged from 0.46 to 0.62. Conclusions: The reliability of the parent-reported IFIS are acceptable, but the concordance between parents reported and objectively measures fitness levels is poor, suggesting that parents' responses may not be able to correctly classify preschoolers according to their fitness level.HighlightsThe convergent validity and reliability (test-retest) values of the IFIS parent scale are moderately acceptable for assessing physical fitness in children aged 3-5 years.However, the results of concordance show that criterion validity is poor suggesting that parents' responses may not be able to correctly classify preschoolers according to their fitness level.Considering that the fitness level at these ages is fairly homogeneous, it seems difficult for parents to discriminate between the fitness levels of their children. Therefore, it seems necessary to recalibrate the scale in future work.

Menstrual cycle affects iron homeostasis and hepcidin following interval running exercise in endurance-trained women.

PURPOSE: Menstrual cycle phase affects resting hepcidin levels, but such effects on the hepcidin response to exercise are still unclear. Thus, we investigated the hepcidin response to running during three different menstrual cycle phases. METHODS: Twenty-one endurance-trained eumenorrheic women performed three identical interval running protocols during the early-follicular phase (EFP), late-follicular phase (LFP), and mid-luteal phase (MLP). The protocol consisted of 8 × 3 min bouts at 85% of the maximal aerobic speed, with 90-s recovery. Blood samples were collected pre-exercise and at 0 h, 3 h and 24 h post-exercise. RESULTS: Data presented as mean ± SD. Ferritin were lower in the EFP than the LFP (34.82 ± 16.44 vs 40.90 ± 23.91 ng/ml, p = 0.003), while iron and transferrin saturation were lower during the EFP (58.04 ± 19.70 µg/dl, 14.71 ± 5.47%) compared to the LFP (88.67 ± 36.38 µg/dl, 22.22 ± 9.54%; p < 0.001) and the MLP (80.20 ± 42.05 µg/dl, 19.87 ± 10.37%; p = 0.024 and p = 0.045, respectively). Hepcidin was not affected by menstrual cycle (p = 0.052) or menstrual cycle*time interaction (p = 0.075). However, when comparing hepcidin at 3 h post-exercise, a moderate and meaningful effect size showed that hepcidin was higher in the LFP compared to the EFP (3.01 ± 4.16 vs 1.26 ± 1.25 nMol/l; d = 0.57, CI = 0.07-1.08). No effect of time on hepcidin during the EFP was found either (p = 0.426). CONCLUSION: The decrease in iron, ferritin and TSAT levels during the EFP may mislead the determination of iron status in eumenorrheic athletes. However, although the hepcidin response to exercise appears to be reduced in the EFP, it shows no clear differences between the phases of the menstrual cycle (clinicaltrials.gov: NCT04458662).

Effects of Circuit Resistance Training on Body Composition, Strength, and Cardiorespiratory Fitness in Middle-Aged and Older Women: A Systematic Review and Meta-Analysis.

A systematic review with meta-analysis was conducted to evaluate the effects of circuit resistance training (CRT) on cardiorespiratory fitness, strength, and body composition in middle-aged and older women. Sixteen studies were included in the meta-analysis. The CRT interventions led to a significant decrease in weight, body mass index, and fat mass along with an increase in muscle mass. Significant differences were found in the fat mass and a trend to develop muscle mass when compared with the control group. CRT led to a significant increase in VO2max, walking endurance, and time to exhaustion; likewise, significant differences were observed when compared with the control group. CRT had a moderate and large favorable effect on arm, trunk, and lower limb strength. Furthermore, the increases in strength observed in the CRT were significantly greater than the changes observed in the control group. In middle-aged and older women, CRT improved cardiorespiratory fitness and strength and optimized body composition.

Patterns of Active Commuting to School in Spanish Preschool Children and Its Associations with Socio-Economic Factors: The PREFIT Project.

The aims of this study were to describe patterns of active commuting to school (ACS) of preschool children, and to analyse the relationship between ACS and family socio-economic factors. A total of 2636 families of preschoolers (3-to-5 years old) were asked to complete a questionnaire at home about the mode of commuting to school of their children and marital status, educational level, and profession of both father and mother. Chi-square analyses were applied to compare ACS between school grades and gender of the children. To analyse the association of ACS with socio-economic factors, logistic regression analyses were performed. Almost 50% of participants reported ACS of their offspring, with a higher rate in 3rd preprimary grade (5 years old) than in 1st and 2nd preprimary grades (3- and 4-years old. All, p < 0.05). Those preschool children who had parents with lower educational level and no managerial work had higher odds to ACS than those who had parents with higher educational level and managerial work (all, p ≤ 0.001). Around half of the Spanish preschool children included in this study commuted actively to school and families with lower educational levels or worse employment situation were related to active commuting to school.

Effect of Different Types of Face Masks on the Ventilatory and Cardiovascular Response to Maximal-Intensity Exercise.

The development of new models of face masks makes it necessary to compare their impact on exercise. Therefore, the aim of this work was to compare the cardiopulmonary response to a maximal incremental test, perceived ventilation, exertion, and comfort using FFP2 or Emotion masks in young female athletes. Thirteen healthy sportswomen (22.08 ± 1.75 years) performed a spirometry, and a graded exercise test on a treadmill, with a JAEGER® Vyntus CPX gas analyzer using an ergospirometry mask (ErgoMask) or wearing the FFP2 or the Emotion mask below the ErgoMask, randomized on 3 consecutive days. Also, menstrual cycle status was monitored to avoid possible intrasubject alterations. The results showed lower values for the ErgoMask+FFP2, compared to ErgoMask or ErgoMask+Emotion, in forced vital capacity (3.8 ± 0.2, 4.5 ± 0.2 and 4.1 ± 0.1 l, respectively); forced expiratory volume in 1 s (3.3 ± 0.2, 3.7 ± 0.2 and 3.5 ± 0.1 l); ventilation (40.9 ± 1.5, 50.6 ± 1.5 and 46.9 ± 1.2 l/min); breathing frequency (32.7 ± 1.1, 37.4 ± 1.1 and 35.3 ± 1.4 bpm); VE/VO2 (30.5 ± 0.7, 34.6 ± 0.9 and 33.6 ± 0.7); VE/VCO2 (32.2 ± 0.6, 36.2 ± 0.9 and 34.4 ± 0.7) and time to exhaustion (492.4 ± 9.7, 521.7 ± 8.6 and 520.1 ± 9.5 s) and higher values in inspiratory time (0.99 ± 0.04, 0.82 ± 0.03 and 0.88 ± 0.03 s). In conclusion, in young healthy female athletes, the Emotion showed better preservation of cardiopulmonary responses than the FFP2.

Liver and kidney function markers among gym users: the role of dietary supplement usage.

Dietary supplements have been increasingly used by gym users and are often consumed without the guidance of a health professional. Moreover, the indiscriminate supplements use can have adverse health effects, such as changes in liver and kidney function. The aim of this study was to verify the association between dietary supplements intake with alterations in the liver and kidney function among gym users. A cross-sectional study was conducted with 594 gym users (mean age 37 (sd 14) years, 55·2 % women) from a city in southern Brazil. A questionnaire was used to evaluate the use of dietary supplements. The markers of the liver (alanine aminotransferase, aspartate aminotransferase (AST), alkaline phosphatase, γ-glutamyltransferase) and renal (creatinine and urea) function were also evaluated on a subsample of the study population. Data were analysed by binary logistic regression, adjusted for sex, age and education. The prevalence of dietary supplement intake was 36·0 %. Individuals who intake dietary supplements showed a higher prevalence to present slight alterations in the AST enzyme and in the urea after adjustments for potential confounders. In conclusion, the use of dietary supplement was associated with slight alterations in AST enzyme and in the urea among gym users. These findings show the importance of using supplements correctly, especially with guidance from professionals trained to avoid possible risks to health.

Effects of Whole-Body Vibration Training on Body Composition, Cardiometabolic Risk, and Strength in the Population Who Are Overweight and Obese: A Systematic Review With Meta-analysis.

OBJECTIVES: To assess the effects of whole-body vibration training (WBVT) on body composition, metabolic and cardiovascular risk variables, and lower limb strength in participants who are overweight/obese. DATA SOURCES: A systematic review with meta-analysis was conducted in 3 databases (PubMed-MEDLINE, Web of Science, and Cochrane Library) from inception through to January 26, 2020. STUDY SELECTION: Studies analyzing the effect of WBVT on body composition variables, metabolic profile, blood pressure, heart rate, and lower limb strength in the population who are overweight/obese, with interventions of a minimum length of 2 weeks were included. DATA EXTRACTION: After applying the inclusion and exclusion criteria, 23 studies involving 884 participants who were obese/overweight (experimental group: 543; weight=79.9 kg; body mass index (BMI) =31.3 kg/m2, obesity class I according to World Health Organization) were used in the quantitative analysis. The sex of the participants involved in the studies were as follows: (1) 17 studies included only female participants; (2) 1 study included only boys, and (3) 5 studies included both sexes. Meta-analysis, subgroup analysis, and meta-regression methods were used to calculate the mean difference and standardized mean difference (SMD; ± 95% confidence intervals [CIs]) as well as to analyze the effects of pre-post intervention WBVT and differences from control groups. DATA SYNTHESIS: WBVT led to a significant decrease in fat mass (-1.07 kg, not clinically significant). In addition, WBVT reduced systolic blood pressure (-7.01 mmHg, clinically significant), diastolic blood pressure (-1.83 mmHg), and heart rate (-2.23 bpm), as well as increased the lower extremity strength (SMD=0.63; range, 0.40-0.86). On the other hand, WBVT did not modify the weight, BMI, muscle mass, cholesterol, triglycerides, or glucose. CONCLUSIONS: WBVT could be an effective training modality to reduce blood pressure (clinically relevant) and resting heart rate. In addition, WBVT led to improved lower limb strength. However, these findings were not consistent with significant improvements on other variables associated with metabolic syndrome (body composition, cholesterol, triglycerides, glucose).

Methodological Approach of the Iron and Muscular Damage: Female Metabolism and Menstrual Cycle during Exercise Project (IronFEMME Study).

Background: The increase in exercise levels in the last few years among professional and recreational female athletes has led to an increased scientific interest about sports health and performance in the female athlete population. The purpose of the IronFEMME Study described in this protocol article is to determine the influence of different hormonal profiles on iron metabolism in response to endurance exercise, and the main markers of muscle damage in response to resistance exercise; both in eumenorrheic, oral contraceptive (OC) users and postmenopausal well-trained women. Methods: This project is an observational controlled randomized counterbalanced study. One hundered and four (104) active and healthy women were selected to participate in the IronFEMME Study, 57 of which were eumenorrheic, 31 OC users and 16 postmenopausal. The project consisted of two sections carried out at the same time: iron metabolism (study I) and muscle damage (study II). For the study I, the exercise protocol consisted of an interval running test (eight bouts of 3 min at 85% of the maximal aerobic speed), whereas the study II protocol was an eccentric-based resistance exercise protocol (10 sets of 10 repetitions of plate-loaded barbell parallel back squats at 60% of their one repetition maximum (1RM) with 2 min of recovery between sets). In both studies, eumenorrheic participants were evaluated at three specific moments of the menstrual cycle: early-follicular phase, late-follicular phase and mid-luteal phase; OC users performed the trial at two moments: withdrawal phase and active pill phase. Lastly, postmenopausal women were only tested once, since their hormonal status does not fluctuate. The three-step method was used to verify the menstrual cycle phase: calendar counting, blood test confirmation, and urine-based ovulation kits. Blood samples were obtained to measure sex hormones, iron metabolism parameters, and muscle damage related markers. Discussion: IronFEMME Study has been designed to increase the knowledge regarding the influence of sex hormones on some aspects of the exercise-related female physiology. Iron metabolism and exercise-induced muscle damage will be studied considering the different reproductive status present throughout well-trained females' lifespan.

Impact of COVID-19 Confinement on Physical Activity and Sedentary Behaviour in Spanish University Students: Role of Gender.

During the COVID-19 pandemic, entire populations were instructed to live in home-confinement to prevent the expansion of the disease. Spain was one of the countries with the strictest conditions, as outdoor physical activity was banned for nearly two months. This study aimed to analyse the changes in physical activity and sedentary behaviours in Spanish university students before and during the confinement by COVID-19 with special focus on gender. We also analysed enjoyment, the tools used and motivation and impediments for doing physical activity. An online questionnaire, which included the International Physical Activity Questionnaire Short Form and certain "ad hoc" questions, was designed. Students were recruited by distributing an invitation through the administrative channels of 16 universities and a total of 13,754 valid surveys were collected. Overall, university students reduced moderate (-29.5%) and vigorous (-18.3%) physical activity during the confinement and increased sedentary time (+52.7%). However, they spent more time on high intensity interval training (HIIT) (+18.2%) and mind-body activities (e.g., yoga) (+80.0%). Adaptation to the confinement, in terms of physical activity, was handled better by women than by men. These results will help design strategies for each gender to promote physical activity and reduce sedentary behaviour during confinement periods.

Body Composition Changes after a Weight Loss Intervention: A 3-Year Follow-Up Study.

Studies comparing different types of exercise-based interventions have not shown a consistent effect of training on long-term weight maintenance. The aim of this study was to compare the effects of exercise modalities combined with diet intervention on body composition immediately after intervention and at 3 years' follow-up in overweight and obese adults. Two-hundred thirty-nine people (107 men) participated in a 6-month diet and exercise-based intervention, split into four randomly assigned groups: strength group (S), endurance group (E), combined strength and endurance group (SE), and control group (C). The body composition measurements took place on the first week before the start of training and after 22 weeks of training. In addition, a third measurement took place 3 years after the intervention period. A significant interaction effect (group × time) (p = 0.017) was observed for the fat mass percentage. It significantly decreased by 5.48 ± 0.65%, 5.30 ± 0.65%, 7.04 ± 0.72%, and 4.86 ± 0.65% at post-intervention for S, E, SE, and C, respectively. Three years after the intervention, the fat mass percentage returned to values similar to the baseline, except for the combined strength and endurance group, where it remained lower than the value at pre-intervention (p < 0.05). However, no significant interaction was discovered for the rest of the studied outcomes, neither at post-intervention nor 3 years later. The combined strength and endurance group was the only group that achieved lower levels of fat mass (%) at both post-intervention and 3 years after intervention, in comparison with the other groups.

Indirect Markers of Muscle Damage Throughout the Menstrual Cycle.

CONTEXT: The indirect markers of muscle damage have been previously studied in females. However, inconclusive results have been found, possibly explained by the heterogeneity regarding monitoring and verification of menstrual-cycle phase. PURPOSE: To determine whether the fluctuations in sex hormones during the menstrual cycle influence muscle damage. METHODS: A total of 19 well-trained eumenorrheic women (age 28.6 [5.9] y; height 163.4 [6.1] cm; weight 59.6 [5.8] kg body mass) performed an eccentric-based resistance protocol consisting of 10 × 10 back squats at 60% of their 1-repetition maximum on the early follicular phase (EFP), late follicular phase, and midluteal phase of the menstrual cycle. Range of motion, muscle soreness, countermovement jump, and limb circumferences were evaluated prior to 24 and 48 hours postexercise. Perceived exertion was evaluated after each set. RESULTS: Differences in sex hormones indicated that tests were adequately performed in the different menstrual-cycle phases. Prior to exercise, muscle soreness was higher in the EFP (4.7 [7.7]) than in the late follicular phase (1.1 [3.2]; P = .045). No other variables showed significant differences between phases. Time-point differences (baseline, 24, and 48 h) were observed in knee range of motion (P = .02), muscle soreness, countermovement jump, and between sets for perceived exertion (P < .001). CONCLUSION: Although the protocol elicited muscle damage, hormonal fluctuations over the menstrual cycle did not seem to affect indirect markers of muscle damage, except for perceived muscle soreness. Muscle soreness was perceived to be more severe before exercise performed in EFP, when estrogen concentrations are relatively low. This may impair women's predisposition to perform strenuous exercise during EFP.

Hepcidin response to interval running exercise is not affected by oral contraceptive phase in endurance-trained women.

The use of oral contraceptives (OCs) by female athletes may lead to improved iron status, possibly through the regulation of hepcidin by sex hormones. The present work investigates the response of hepcidin and interleukin-6 (IL-6) to an interval exercise in both phases of the OC cycle. Sixteen endurance-trained OC users (age 25.3 ± 4.7 years; height 162.4 ± 5.7 cm; body mass 56.0 ± 5.7 kg; body fat percentage 24.8 ± 6.0%; peak oxygen consumption [VO2peak ]: 47.4 ± 5.5 mL min-1 kg-1 ) followed an identical interval running protocol during the withdrawal and active pill phases of the OC cycle. This protocol consisted of 8 × 3 minutes bouts at 85% VO2peak speed with 90 seconds recovery intervals. Blood samples were collected pre-exercise, and at 0 hour, 3 hours, and 24 hours post-exercise. Pre-exercise 17ß-estradiol was lower (P = .001) during the active pill than the withdrawal phase (7.91 ± 1.81 vs 29.36 ± 6.45 pg/mL [mean ± SEM]). No differences were seen between the OC phases with respect to hepcidin or IL-6 concentrations, whether taking all time points together or separately. However, within the withdrawal phase, hepcidin concentrations were higher at 3 hours post-exercise (3.33 ± 0.95 nmol/L) than at pre-exercise (1.04 ± 0.20 nmol/L; P = .005) and 0 hour post-exercise (1.41 ± 0.38 nmol/L; P = .045). Within both OC phases, IL-6 was higher at 0 hour post-exercise than at any other time point (P < .05). Similar trends in hepcidin and IL-6 concentrations were seen at the different time points during both OC phases. OC use led to low 17ß-estradiol concentrations during the active pill phase but did not affect hepcidin. This does not, however, rule out estradiol affecting hepcidin levels.

Exercise-Induced Muscle Damage During the Menstrual Cycle: A Systematic Review and Meta-Analysis.

ABSTRACT: Romero-Parra, N, Cupeiro, R, Alfaro-Magallanes, VM, Rael, B, Rubio-Arias, JA, Peinado, AB, and Benito, PJ, IronFEMME Study Group. Exercise-induced muscle damage during the menstrual cycle: A systematic review and meta-analysis. J Strength Cond Res 35(2): 549-561, 2021-A strenuous bout of exercise could trigger damage of muscle tissue, and it is not clear how sex hormone fluctuations occurring during the menstrual cycle (MC) affect this response. The aims of this study were to systematically search and assess studies that have evaluated exercise-induced muscle damage (EIMD) in eumenorrheic women over the MC and to perform a meta-analysis to quantify which MC phases display the muscle damage response. The guidelines of the Preferred Reported Items for Systematic Reviews and Meta-Analysis were followed. A total of 19 articles were analyzed in the quantitative synthesis. Included studies examined EIMD in at least one phase of the following MC phases: early follicular phase (EFP), late follicular phase (LFP), or midluteal phase (MLP). The meta-analysis demonstrated differences between MC phases for delayed onset muscle soreness (DOMS) and strength loss (p < 0.05), whereas no differences were observed between MC phases for creatine kinase. The maximum mean differences between pre-excercise and post-exercise for DOMS were EFP: 6.57 (4.42, 8.71), LFP: 5.37 (2.10, 8.63), and MLP: 3.08 (2.22, 3.95), whereas for strength loss were EFP: -3.46 (-4.95, -1.98), LFP: -1.63 (-2.36, -0.89), and MLP: -0.72 (-1.07, -0.36) (p < 0.001). In conclusion, this meta-analysis suggests that hormone fluctuations throughout the MC affect EIMD in terms of DOMS and strength loss. Lower training loads or longer recovery periods could be considered in the EFP, when sex hormone concentrations are lower and women may be more vulnerable to muscle damage, whereas strength conditioning loads could be enhanced in the MLP.

Menopause Delays the Typical Recovery of Pre-Exercise Hepcidin Levels after High-Intensity Interval Running Exercise in Endurance-Trained Women.

Menopause commonly presents the gradual accumulation of iron in the body over the years, which is a risk factor for diseases such as cancer, osteoporosis, or cardiovascular diseases. Running exercise is known to acutely increase hepcidin levels, which reduces iron absorption and recycling. As this fact has not been studied in postmenopausal women, this study investigated the hepcidin response to running exercise in this population. Thirteen endurance-trained postmenopausal women (age: 51.5 ± 3.89 years; height: 161.8 ± 4.9 cm; body mass: 55.9 ± 3.6 kg; body fat: 24.7 ± 4.2%; peak oxygen consumption: 42.4 ± 4.0 mL·min-1·kg-1) performed a high-intensity interval running protocol, which consisted of 8 × 3 min bouts at 85% of the maximal aerobic speed with 90-second recovery. Blood samples were collected pre-exercise, 0, 3, and 24 hours post-exercise. As expected, hepcidin exhibited higher values at 3 hours post-exercise (3.69 ± 3.38 nmol/L), but also at 24 hours post-exercise (3.25 ± 3.61 nmol/L), in comparison with pre-exercise (1.77 ± 1.74 nmol/L; p = 0.023 and p = 0.020, respectively) and 0 hour post-exercise (2.05 ± 2.00 nmol/L; p = 0.021 and p = 0.032, respectively) concentrations. These differences were preceded by a significant increment of interleukin-6 at 0 hour post-exercise (3.41 ± 1.60 pg/mL) compared to pre-exercise (1.65 ± 0.48 pg/m, p = 0.003), 3 hours (1.50 ± 0.00 pg/mL, p = 0.002) and 24 hours post-exercise (1.52 ± 0.07 pg/mL, p = 0.001). Hepcidin peaked at 3 hours post-exercise as the literature described for premenopausal women but does not seem to be fully recovered to pre-exercise levels within 24 hours post-exercise, as it would be expected. This suggests a slower recovery of basal hepcidin levels in postmenopausal women, suggesting interesting applications in order to modify iron homeostasis as appropriate, such as the prevention of iron accumulation or proper timing of iron supplementation.