The menopause transition is associated with increased cardiovascular disease (CVD) risk. Cardiorespiratory fitness (CRF) is inversely associated with CVD risk in healthy populations. CRF thus represents a responsive target for physical activity (PA) interventions in menopausal populations. The aims were: (1) to investigate the impact of PA interventions on CRF and CVD risk factors, respectively, in perimenopausal and menopausal women, and (2) to examine the association between changes in CRF and CVD risk factors following PA interventions.

Five databases (PubMed, EMBASE, Web of Science, CENTRAL, SPORTDiscus) were searched from inception to December 2023 for randomised controlled trials of PA interventions in menopausal females with non-active controls. The primary outcome was CRF, presented as VO_2max. The Cochrane Risk of Bias Tool was used to assess bias. Heterogeneity was observed using I². Effect measures were presented as Mean Difference (MD) with 95% Confidence Interval (CI). Meta-regression was conducted to examine the relationship between changes in VO_2max and reduction in CVD risk.

Seventy-eight studies with 5332 participants were included in meta-analysis. For VO_2max, there was a favourable effect of exercise versus control (3.51 mL/kg/min, 95% CI 2.75 to 4.27, 1968 participants, 30 trials). Considerable heterogeneity was observed. Meta-regression indicated a small, significant inverse association between changes in VO_2max and changes in systolic blood pressure in sensitivity analysis.

All types of PA improved CRF. Moreover, improvements in CRF through PA intervention may be associated with concomitant reductions in systolic blood pressure, which is a major risk for CVD. Many outcomes had unexplained heterogeneity and unclear risk of bias due to lack of transparent reporting. Future research should investigate age and PA intensity as moderator variables. Future RCTs should focus on transparent reporting.

Team sports often involve intermittent sprints. During these activities the Phosphocreatine-ATP buffer (ATP-PCr) signifies the major anaerobic energy substrate. While the effects of ketogenic diets (KD) on carbohydrate and fat metabolism during endurance exercise are widely reported, we explored keto-adaptation in ATP-PCr metabolism during intermittent sprint exercise.

Following a within-subject repeated measures design, 15 recreationally active participants (7 men, 8 women, aged 25.1±6.4 years) performed cycle ergometer intermittent sprints (6×10 s sprints, 2 min recovery) with VO₂ and blood lactate measurements for energy system calculations. These laboratory tests were performed in alternate weeks; First, twice at baseline on their habitual diet (HD) (35% CHO, 45% fat, 20% protein) and thereafter over a 6-week KD (7% CHO, 66% fat, 28% protein).

Repeated measures ANOVA’s and Bonferroni tests revealed ATP-PCr derived energy increased significantly from HD to KD week 6 (+22.0±43.15 J; P=0.019; ES=0.47). From HD to KD week 2, anaerobic glycolytic contribution lowered (− 14.4±28.16 J; P=0.031; ES=− 0.10) and peak blood [lactate] reduced significantly (− 2.92±0.851 mmol; P=0.004; ES=− 0.73). There was no statistically significant within-subject change in mean sprint power (P=0.356).

The 6-week KD did not compromise intermittent sprint performance. The findings suggest that the ATP-PCr energy pathway may be a novel site of metabolic keto-adaptation. This, combined with the lowered blood [lactate] we observed, presents desirable metabolic adaptations for intermittent sprint sport athletes.

The slow component of O₂ uptake (VO₂SC) is attenuated when brief periods of recovery are initiated at exercise onset but the impact of introducing intermittent recovery periods after the primary increase in VO₂ on the VO₂SC are unknown.

This study examined the effect of brief bouts of recovery initiated after the primary rise in VO₂ on the amplitude of the VO₂SC.

Seven healthy men [30±10 years, 179±8 cm, 89.2±8.2 kg (±SD)] performed 6 bouts of cycling exercise; 2 bouts of continuous exercise (CONT) and 4 bouts of intermittent exercise (INT, HINT) with work-recovery intervals of 10 s and 3 s. CONT and INT trials consisted of step-transitions from 20 W to a work rate (WR) corresponding to 50% of the difference between VO_2peak and gas exchange threshold (Δ50). The WR for HINT was calculated to match the total work performed in the CONT condition.

The VO₂SC, indicated by ΔVO_{2(6–3 min)}, was eliminated INT (–81±201 mL/min) compared to CONT (597±164 mL/min) and HINT (409±212 mL/min) although there were no differences between the phase II VO₂ kinetic parameters.

Introducing 3 s of recovery every 10 s following 3 min of heavy intensity exercise eliminated the VO₂SC in INT but had no effect on HINT. These findings demonstrate that introducing brief intermittent exercise-recovery periods during heavy intensity exercise lowers exercise intensity domain; however, work-matched intermittent heavy intensity exercise results in similar dynamics to CONT.

Standard heat acclimation (HA) protocols (low-moderate intensity over a continuous 7–14 days) restore performance and thermoregulation but lack specificity and practicality for intermittent sports athletes. This study compared different pedal resistances in a 3-week intermittent sprint-based HA protocol.

Fourteen physically active adults were assigned to a sprint pedal resistance training group (TG): 0.075 kg/kg (7.5TG, 6 males, 1 female) or 0.085 kg/kg (8.5TG, 5 males, 2 females). Participants completed baseline incremental time to exhaustion test (TTE), continued with own training for 3 weeks before post-control TTE, then carried out 6×15 s cycle sprints with 30 s recovery followed by 30 min low intensity cycling thrice weekly for 3 weeks before completing post-HA TTE test. Testing and HA were completed at 38 °C and 30% relative humidity.

Both groups improved TTE from baseline to post-HA (7.5TG: 9.6%±10.8%, 8.5TG: 7.4%±3.1%) and post-control to post-HA (7.5TG: 11.0%±11.7%, 8.5TG: 6.7%±3.9%). Maximal power improved from baseline to post-HA (7.5TG: 293±40 W vs. 321±46 W, 8.5TG: 318±90 W vs. 339±96 W), while only 7.5TG improved maximal power from post-control to post-HA (289±42 W vs. 321±46 W). From baseline to post-HA and post-control to post-HA, only 7.5TG increased time till maximum skin temperature (460±76 s vs. 509±75 s, 461±72 s vs. 509±75 s, respectively) and minimum core-skin gradient (461±71 s vs. 510±74 s, 455±75 s vs. 510±74 s, respectively), while exercising core temperature remained unchanged in both groups. Both groups increased sweat rate (7.5TG: 7.0±3.4 mg/cm²/min vs. 9.6±4.1 mg/cm²/min, 8.5TG: 5.7±3.6 mg/cm²/min vs. 8.3±4.3 mg/cm²/min). Only 7.5TG delayed the onset of blood lactate accumulation from baseline to post-HA (259±126 s vs. 354±86 s).

Intermittent sprint-based HA improves TTE performance and sweat rate while a lighter sprint pedal resistance offers, greater thermal adaptation and fatigue tolerance.

Resistance training can improve performance in power and speed sports. This study aimed to compare the effect of 8 weeks of high-intensity interval resistance training (HIIRT) compared to traditional resistance training (RT) on the performance and physiological indicators of young female rowers.

Sixteen young female rowers who had more than 3 years of professional rowing experience were randomly divided into two groups: RT and HIIRT (n=8 in each group). Resistance training for two groups was performed in the form of RT and HIIRT for 8 weeks, three sessions per week, with additional training (three rowing sessions+one session of ergometer+two sessions of running and central stability training). Functional tests and physiological adaptations were measured before and after the RT and HIIRT programs.

The statistical analysis of the data showed that the 2000-m rowing ergometer performance improved significantly in both groups (P<0.0001). The magnitude of this performance increase was greater in the HIIRT group. Maximum oxygen consumption (VO_2max) in the HIIRT group revealed a significant difference before and after 8 weeks of training (P=0.002). Changes in the respiratory exchange rate (RER) were significantly affected by both RT and HIIRT (P<0.01). However, changes in lactate levels were not significant in either training group (P>0.05).

According to the results of the present study, it seems that HIIRT is more effective than traditional RT exercises in enhancing the physiological characteristics and performance of young female rowers.

Recovery within and between rounds is crucial to combat sports performance. We sought to determine whether sprint interval training (SIT) improves recovery dynamics and aerobic performance.

Eleven male kickboxing athletes (26±5 years; body mass index 25±3 kg/m²) were recruited. Participants were tested three times for VO_2peak/time to exhaustion and critical power; baseline, 3 weeks control, 3 weeks of SIT (8×10 s lower body sprints followed by a maximum of 10 min recovery before completing 8×10 s upper body sprints). During SIT session 1 and 9 continuous gas analysis was performed.

There was a significant reduction in recovery time between lower and upper body sprints with training (session 1: 441±150 s; session 9: 268±10 s; P<0.01; d=2.77) and change in oxygen off-kinetics amplitude (session1: 3.0±0.7 L/min, session 9: 3.6±1.0 L/min; P<0.05; d=−1.77), VO₂ end (session 1: 0.59±0.19 L/min, session 9: 0.81±0.21 L/min; P<0.05, d=−0.90), time constant (session 1: 81±21 s; session 9: 60±11 s; P<0.05; d=1.03). Following training there was a significant improvement in critical power (P<0.05; η²_p=0.72) time to exhaustion (P<0.05; η²_p=0.30) but not VO_2peak (P>0.05).

SIT improves recovery time associated and aerobic performance associated with improved oxygen off-kinetics. Therefore, training needs to focus on improving oxygen off-kinetics to enhance combat performance.

Post-exercise hypotension (PEH) following prolonged dynamic exercise is induced by an increase in systemic vascular conductance via skeletal muscle vasodilation, which may occur not only in the arteries but also in the veins, and the vasodilated regions may contribute to greater venous pooling in the exercised limbs. However, the contribution of venous distention to PEH is unclear. Therefore, we aimed to evaluate venous compliance in previously exercised muscles in a preliminary study.

Seven participants performed a single 60-min session of upright cycle ergometry at 60% of heart rate reserve. Calf venous compliance was measured using venous congestion plethysmography before and 45 min following exercise in Trial 1. Stroke volume and femoral arterial blood flow were determined using ultrasonography at the same time points in Trial 2. Heart rate and blood pressure were monitored during both trials.

Mean arterial pressure significantly decreased between the start and ~30 min following the end of exercise (82 ± 6 mmHg vs. 76 ± 6 mmHg, respectively, in Trial 1; 79 ± 6 mmHg vs. 74 ± 5 mmHg, respectively, in Trial 2; P<0.05). Pre- and post-exercise stroke volume did not significantly differ. Blood flow and vascular conductance in the femoral artery significantly increased from 641 ± 84 mL/min and 8.13 ± 0.79 mL/min/mmHg pre-exercise to 773 ±  121 mL/min and 10.55 ± 1.00 mL/min/mmHg post-exercise, respectively (P<0.05). Pre- and post-exercise calf venous compliance did not significantly differ.

Our findings demonstrate that vasodilation in the active limb increases during exercise, but the resulting PEH does not affect venous compliance.