The aim of the study was to analyse the cardiorespiratory response to exercise during an oral contraceptive (OC) cycle in endurance-trained women.
Sixteen low-dose monophasic OC pill (OCP) users ...performed an interval-running protocol. The protocol consisted of eight 3 min bouts at 85% of participants' maximal aerobic speed (vV̇
o
2peak
) with a 90s recovery at 30% vV̇
o
2peak
in two OC phases: a withdrawal phase (WP) and an active pill phase (APP). The non-parametric Wilcoxon test was applied to analyse differences (p < 0.05) in performance variables between OC cycle phases.
Throughout the high-intensity intervals, higher ventilation (WP 80.90 ± 11.49 L/min, APP 83.10 ± 13.33 L/min; p < 0.001) and relative perceived exertion (WP 14.51 ± 2.58, APP 15.11 ± 3.11; p = 0.001) during the APP were found, whereas carbon dioxide production (WP 2040.92 ± 262.93 mL/min, APP 2010.25 ± 305.68 mL/min; p = 0.003) was higher in the WP. During the active recovery intervals, ventilation (WP 65.78 ± 9.90 L/min, APP 67.88 ± 12.66 L/min; p < 0.001) was higher in the APP, while heart rate (WP 159.93 ± 10.26 bpm, APP 159.74 ± 12.83 bpm; p = 0.029) was higher in the WP.
An increase in ventilation occurs during the APP, which is accompanied by higher perceived exertion. Therefore, coaches and athletes should be aware of these variations, especially perceived exertion, in regard to women's training programmes, in order to improve their performance, wellness and adherence to physical activity.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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;
= 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;
= 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 ferritin has been proposed as a predictor of hepcidin concentrations in response to exercise. However, this fact has not been studied in physically-active women. Therefore, the main objective ...of this study was to analyse the hepcidin response at different ferritin status before and after running exercise in physically active females. Fifteen eumenorrheic women performed a 40-min running protocol at 75% of VO2peak speed in different menstrual cycle phases (early-follicular phase, mid-follicular phase and luteal phase). Blood samples were collected pre-exercise, 0h post-exercise and 3h post-exercise. For statistics, participants were divided into two groups according to their pre-exercise ferritin levels (<20 and ≥20 μg/L). Through menstrual cycle, hepcidin was lower in both early follicular phase (p=0.024; 64.81±22.48 ng/ml) and mid-follicular phase (p=0.007; 64.68±23.91 ng/ml) for <20 μg/L ferritin group, in comparison with ≥20 μg/L group (81.17±27.89 and 79.54±22.72 ng/ml, respectively). Hepcidin showed no differences between both ferritin groups in either pre-exercise, 0h post-exercise and 3h post-exercise. Additionally, no association between pre-exercise ferritin and hepcidin levels 3h post-exercise (r=-0.091; p=0.554) was found. Menstrual cycle phase appears to influence hepcidin levels depending on ferritin reserves. In particular, physically-active females with depleted ferritin reserves seems to present lower hepcidin levels during the early-follicular phase and mid-follicular phase. However, no association between ferritin and hepcidin levels was found in this study. Hence, ferritin levels alone may not be a good predictor of hepcidin response to exercise in this population. Multiple factors such as sexual hormones, training loads and menstrual bleeding must be taken into account.
Iron is necessary for adequate deliver oxygen to the tissues since it is an essential component of the haemoglobin. However, iron deficiency remains a common problem among athletes, particularly for ...women experiencing the menstrual bleeding every month. The iron losses through menstrual blood loss during the early follicular phase (or menses) and an inadequate dietary intake of iron are two important factors contributing to this disease. Furthermore, the large hormonal changes that women experience along the menstrual cycle, especially in oestrogen and progesterone may influence on the optimization of iron absorption. Iron absorption is mainly mediated by hepcidin hormone, which seems to be affected by several stimulus and factors such as oestrogen and progesterone concentrations. Moreover, the regular practice of exercise is another important modulator of this hormone. Therefore, premenopausal active females are the most susceptible population to develop an iron deficiency or iron deficiency anemia, affecting their health and performance due to the less iron availability within the body and consequently a reduction of haemoglobin which compromise the oxygen transport. To date, most studies have not explored the acute post-exercise hepcidin response taking endogenous and exogenous sexual hormones influence into account. This narrative review will focus on how iron homeostasis is modulated by different factors mainly influenced by exercise and female sexual hormones.
To investigate the efficacy and feasibility of three different 8 h time-restricted eating (TRE) schedules (i.e., early, late, and self-selected) compared to each other and to a usual-care (UC) ...intervention on visceral adipose tissue (VAT) and cardiometabolic health in men and women.
Anticipated 208 adults (50% women) aged 30-60 years, with overweight/obesity (25 ≤ BMI<40 kg/m
) and with mild metabolic impairments will be recruited for this parallel-group, multicenter randomized controlled trial. Participants will be randomly allocated (1:1:1:1) to one of four groups for 12 weeks: UC, early TRE, late TRE or self-selected TRE. The UC group will maintain their habitual eating window and receive, as well as the TRE groups, healthy lifestyle education for weight management. The early TRE group will start eating not later than 10:00, and the late TRE group not before 13:00. The self-selected TRE group will select an 8 h eating window before the intervention and maintain it over the intervention. The primary outcome is changes in VAT, whereas secondary outcomes include body composition and cardiometabolic risk factors.
This study will determine whether the timing of the eating window during TRE impacts its efficacy on VAT, body composition and cardiometabolic risk factors and provide insights about its feasibility.
Exercise reduces adiposity, but its influence on bone marrow fat fraction (BMFF) is unknown; nor is it known whether a reduction in liver fat content mediates this reduction.CONTEXTExercise reduces ...adiposity, but its influence on bone marrow fat fraction (BMFF) is unknown; nor is it known whether a reduction in liver fat content mediates this reduction.(i) To determine whether incorporating exercise into a lifestyle program reduces the lumbar spine (LS)-BMFF, and (ii), to investigate whether changes in liver fat mediate any such effect.OBJECTIVES(i) To determine whether incorporating exercise into a lifestyle program reduces the lumbar spine (LS)-BMFF, and (ii), to investigate whether changes in liver fat mediate any such effect.Ancillary analysis of a two-arm, parallel, non-randomized clinical trial.DESIGNAncillary analysis of a two-arm, parallel, non-randomized clinical trial.Primary care centres in Vitoria-Gasteiz (Spain).SETTINGPrimary care centres in Vitoria-Gasteiz (Spain).A total of 116 children with overweight/obesity were assigned to a 22-week family-based lifestyle program (control group n=57) or the same program plus an exercise intervention (exercise group n=59.PARTICIPANTSA total of 116 children with overweight/obesity were assigned to a 22-week family-based lifestyle program (control group n=57) or the same program plus an exercise intervention (exercise group n=59.The compared interventions consisted of a family-based lifestyle program (two 90-minute sessions/month) and the same program plus supervised exercise (three 90-minute sessions/week).INTERVENTIONSThe compared interventions consisted of a family-based lifestyle program (two 90-minute sessions/month) and the same program plus supervised exercise (three 90-minute sessions/week).The primary outcome examined was the change in LS-BMFF between baseline and 22 weeks, as estimated by MRI. The effect of changes in hepatic fat on LS-BMFF were also recorded.MAIN OUTCOMES AND MEASURESThe primary outcome examined was the change in LS-BMFF between baseline and 22 weeks, as estimated by MRI. The effect of changes in hepatic fat on LS-BMFF were also recorded.Mean weight loss difference between groups was 1.4±0.5 kg favour of the exercise group. Only the children in the exercise group experienced a reduction in LS-BMFF (effect size Cohen d -0.42, CI: -0.86, -0.01). Importantly, 40.9% of the reductions in LS-BMFF were mediated by changes in percentage hepatic fat (indirect effect: β=-0.104, 95%CI=-0.213, -0.019). The impact of changes in hepatic fat on LS-BMFF was independent of weight loss.RESULTSMean weight loss difference between groups was 1.4±0.5 kg favour of the exercise group. Only the children in the exercise group experienced a reduction in LS-BMFF (effect size Cohen d -0.42, CI: -0.86, -0.01). Importantly, 40.9% of the reductions in LS-BMFF were mediated by changes in percentage hepatic fat (indirect effect: β=-0.104, 95%CI=-0.213, -0.019). The impact of changes in hepatic fat on LS-BMFF was independent of weight loss.The addition of exercise to a family-based lifestyle program designed to reduce cardiometabolic risk improves bone health by reducing LS-BMFF in children with overweight or obesity. This beneficial effect on bone marrow appears to be mediated by reductions in liver fat.CONCLUSIONS AND RELEVANCEThe addition of exercise to a family-based lifestyle program designed to reduce cardiometabolic risk improves bone health by reducing LS-BMFF in children with overweight or obesity. This beneficial effect on bone marrow appears to be mediated by reductions in liver fat.
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