Effect of Menstrual Cycle Phase on Fuel Oxidation Post HIT in Women Reproductive Age: A Pilot Study

Women of childbearing age have variations in substrate oxidation rates that can lead to overweight, type II diabetes, and other conditions that may be associated with metabolic inflexibility and the variations in estrogen concentrations observed during the monthly ovarian cycle. Purpose: This study aimed to verify and compare the influence of eight treadmill high-intensity interval training (HIT) sessions on carbohydrate and lipid oxidation rates (CHOox and LIPox, respectively) and intensities of ventilatory anaerobic thresholds (VATs) of women in different phases of the monthly ovarian cycle. Methods: Eleven irregularly active women performed incremental treadmill exercise testing followed by submaximal work-rate running for 45 min to determine VATs, VO2peak, peak velocity (Vpeak), and substrate oxidation rates, before and after a training period, in different phases of their monthly ovarian cycle (follicular phase group, FL, n = 6; luteal phase group, LT, n = 5). The training period consisted of eight HIT sessions, composed each one of eight sets of 60 s running at 100%Vpeak interspersed by 75 s recovery every 48 h. Results: Our results showed no significant differences in VATs intensities between groups. The comparison between groups showed significant differences in relative energy derived from CHO pre- and post-training of −61.42% and −59.26%, respectively, and LIP pre- and post-training of 27.46% and 34.41%, respectively. The relative energy derived from CHO after the training period was 18.89% and 25.50% higher for FL and LT, respectively; consequently, the relative energy derived from LIPox after the training period was 8,45% and 3.46% lower for FL and LT, respectively. Over the training period, Vpeak was ~13.5 km/h, which produced the relative intensities of ~89%VO2peak e ~93%HRpeak for both groups. Conclusion: The monthly ovarian cycle phases promote significant changes in substrate oxidation rates leading to a decrease in CHOox. High-intensity interval training can minimize the differences observed and constitute an alternative intervention

Six HIT Sessions Improve Cardiorespiratory Fitness and Metabolic Flexibility in Insulin Resistant and Insulin Sensitive Adolescents with Obesity

To evaluate the effect of high-intensity interval training (HIT) on the cardiorespiratory performance and substrate oxidation pattern in insulin-resistant and insulin-sensitive obese adolescents. Methods: We recruited 25 obese adolescents in three schools, and trained them in six HIT sessions, comprising of six series at 100% and recovery at 50% peak velocity (Vpeak). For the evaluation, the participants were divided into two groups: insulin-resistant (IR, n = 12; HOMA index ≥3.16) and insulin-sensitive (IS, n = 13). All participants underwent cardiopulmonary and indirect calorimetry testing. We compared the effects of HIT before and after the intervention among the two groups. The data were analyzed using Student’s t and Mann–Whitney (intergroup comparisons) and Student’s t and Wilcoxon (pre- and post-training comparisons) tests; and Cohen’s d (influence of HIT). Results: There was a significant post-training increase in Vpeak, oxygen consumption (VO2), velocity (V), and heart rate (HR) at the exertion intensity at the first ventilatory anaerobic threshold (VAT1) in both groups (p < 0.05; d < 0.02). The exercise promoted changes in substrate oxidation rates of the groups, with an increase in carbohydrate oxidation (CHOox) for both IR (p = 0.064) and IS (p = 0.034). Conclusion: Six HIT sessions improved cardiorespiratory performance in both groups and increased CHOox in insulin-sensitive obese adolescents, suggesting its utility for increasing physical fitness and controlling glycemia in these population groups

Training Mode Comparisons on Cardiorespiratory, Body Composition and Metabolic Profile Adaptations in Reproductive Age Women: A Systemic Review and Meta-Analysis

Purpose: This study aimed to compare the effects of high-intensity interval training (HIT), sprint interval training (SIT) and moderate-intensity continuous training (MICT) on cardiorespiratory fitness (CRF), weight (kg), body fat mass (%), plasma glucose (fasting) and lipid levels in reproductive-age women. Method: The search was conducted in Pubmed, Cochrane Library, Virtual Health Library and Scielo. The meta-analyses were conducted using Review Manager software for random-effects models. The results were presented as standardized mean differences and 95%CI, which were calculated to determine the effect size of HIT/SIT and MICT interventions. Results: Eleven articles meet the inclusion criteria. The analyses demonstrated that all exercise modes improved body composition and metabolic profile, but nevertheless, MICT was significantly better at improving CRF (mL·min−1·kg−1) compared with HIT (2.45 mL·min−1·kg−1 (95% CI: 1.15 to 3.75 mL·min−1·kg−1); p < 0.05; I2 = 0%) and with SIT (0.98 mL·min−1·kg−1 (95% CI: −0.98 to 2.93 mL·min−1·kg−1); p = 0.33; I2 = 53%). Conclusion: Both HIT and SIT have the potential to be used as a training modality in reproductive-age women, with similar effects to MICT on body composition/metabolic markers but inferior effects on CRF, suggesting that HIT/SIT may be considered a “time-efficient component″ of weight management programs. However, the variability in the secondary outcome measures, coupled with the small sample sizes in studies, limits this finding

Training Mode Comparisons on Cardiorespiratory, Body Composition and Metabolic Profile Adaptations in Reproductive Age Women: A Systemic Review and Meta-Analysis

Purpose: This study aimed to compare the effects of high-intensity interval training (HIT), sprint interval training (SIT) and moderate-intensity continuous training (MICT) on cardiorespiratory fitness (CRF), weight (kg), body fat mass (%), plasma glucose (fasting) and lipid levels in reproductive-age women. Method: The search was conducted in Pubmed, Cochrane Library, Virtual Health Library and Scielo. The meta-analyses were conducted using Review Manager software for random-effects models. The results were presented as standardized mean differences and 95%CI, which were calculated to determine the effect size of HIT/SIT and MICT interventions. Results: Eleven articles meet the inclusion criteria. The analyses demonstrated that all exercise modes improved body composition and metabolic profile, but nevertheless, MICT was significantly better at improving CRF (mL·min−1·kg−1) compared with HIT (2.45 mL·min−1·kg−1 (95% CI: 1.15 to 3.75 mL·min−1·kg−1); p −1·kg−1 (95% CI: −0.98 to 2.93 mL·min−1·kg−1); p = 0.33; I2 = 53%). Conclusion: Both HIT and SIT have the potential to be used as a training modality in reproductive-age women, with similar effects to MICT on body composition/metabolic markers but inferior effects on CRF, suggesting that HIT/SIT may be considered a “time-efficient component″ of weight management programs. However, the variability in the secondary outcome measures, coupled with the small sample sizes in studies, limits this finding

Respiratory Muscle Strength in Brazilian Adolescents: Impact of Body Composition

(1) Introduction: Studies on respiratory muscle strength (RMS) in adolescents are controversial. Few studies so far have investigated respiratory muscle strength in Brazilian adolescents and the impact of body composition on it. (2) Objective: to evaluate the respiratory muscle strength of Brazilian adolescents and compare this with nationally and internationally predicted normality values. (3) Method: A cross-sectional study (CAEE: 34634414.5.0000.5479) was carried out with 98 adolescents, where both sexes were divided into four groups: eutrophic (n = 44); overweight (n = 15), obese (n = 25), and severely obese (n = 14). All were submitted to an anthropometric assessment, body composition analysis and manovacuometry. To interpret the results, Analysis of Variance (ANOVA) with Turkey’s post hoc test was used. The Kruskal–Wallis test and Friedman’s post hoc test were used to compare the observed vs. proposed results. A p-value < 0.05 was considered statistically significant. (4) Results: There were no differences among the groups for maximal inspiratory (MIP) and expiratory (MEP) pressures. However, when considering the total sample, we could say that RMS was higher among boys, and there were no significant differences in RMS in relation to the maturational stage. The values obtained for MIP were lower than those suggested for the national equation and higher than those proposed for the international equation. Similarly, the values obtained for MEP were lower than those suggested for the national and international equation. (5) Conclusions: RMS was similar in adolescents with different body compositions and different maturation stages. Adiposity did not interfere with RMS in adolescents. Boys had higher MIP and MEP values compared to girls. Therefore, the reference values proposed by the equations do not consistently match RMS in the adolescents studied. This context reinforces the need for new studies that are related to RMS to establish normality values and propose equations that represent the youth population