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PurposeThe long-term implications of premature birth on autonomic nervous system (ANS) function are unclear. Heart rate recovery (HRR) following maximal exercise is a simple tool to evaluate ANS function and is a strong predictor of cardiovascular disease. Our objective was to determine whether HRR is impaired in young adults born preterm (PYA).MethodsIndividuals born between 1989 and 1991 were recruited from the Newborn Lung Project, a prospectively followed cohort of subjects born preterm weighing < 1500 g with an average gestational age of 28 weeks. Age-matched term-born controls were recruited from the local population. HRR was measured for 2 min following maximal exercise testing on an upright cycle ergometer in normoxia and hypoxia, and maximal aerobic capacity (VO2max) was measured.ResultsPreterms had lower VO2max than controls (34.88 ± 5.24 v 46.15 ± 10.21 ml/kg/min, respectively, p < 0.05), and exhibited slower HRR compared to controls after 1 and 2 min of recovery in normoxia (absolute drop of 20 ± 4 v 31 ± 10 and 41 ± 7 v 54 ± 11 beats per minute (bpm), respectively, p < 0.01) and hypoxia (19 ± 5 v 26 ± 8 and 39 ± 7 v 49 ± 13 bpm, respectively, p < 0.05). After adjusting for VO2max, HRR remained slower in preterms at 1 and 2 min of recovery in normoxia (21 ± 2 v 30 ± 2 and 42 ± 3 v 52 ± 3 bpm, respectively, p < 0.05), but not hypoxia (19 ± 3 v 25 ± 2 and 40 ± 4 v 47 ± 3 bpm, respectively, p > 0.05).ConclusionsAutonomic dysfunction as seen in this study has been associated with increased rates of cardiovascular disease in non-preterm populations, suggesting further study of the mechanisms of autonomic dysfunction after preterm birth.

Background Studies assessing sub-maximal aerobic capacity in non-cirrhotic chronic hepatitis B (CHB) patients are scarce. This study aimed to evaluate sub-maximal aerobic capacity in CHB patients compared to apparently healthy participants (control-group (CG)). Methods A 6-min walk test (6MWT) was performed. The 6-min walk distance (6MWD) was recorded, along with heart-rate (HR), oxy-hemoglobin saturation (SpO 2), blood-pressure, and dyspnea ( ie ; visual analogue scale) at rest (Rest) and at the end (End) of the 6MWT. Additionally, the 6-min walk work (6MWW), and \"estimated cardiorespiratory and muscular chain age\" were calculated. Signs of physical intolerance were determined including abnormal 6MWD ( ie ; 6MWD < lower limit of normal), chronotropic insufficiency (ie ; HREnd < 60% of maximal predicted HR (MPHR)), high dyspnea ( ie ; dyspneaEnd > 5), and desaturation ( ie ; drop in SpO 2 > 5 points). Results Compared to the CG (n=28), the CHB-group (n=26) exhibited significantly lower 6MWD by 61 meters (8%), lower 6MWW by 10%, and lower HR End by 21% (when expressed in bpm) and 17% (when expressed in %MPHR). The CHB-group, compared to the CG, included higher percentages of participants with chronotropic insufficiency and abnormal 6MWD (23.08% vs. 3.57%, and 34.61% vs. 3.57%, respectively). The CHB-group was 8.1 and 14.3 times more likely to have chronotropic insufficiency and abnormal 6MWD than the CG, respectively. CHB accelerated the aging of the \"cardiorespiratory and muscular chain\" by 11 years. Conclusion Non-cirrhotic CHB may contribute to reduced submaximal aerobic capacity and acceleration of \"cardiorespiratory and muscular chain\" aging.

The circulating fibroblast growth factor 23 (FGF23) is a potential therapeutic target for cardiorenal syndrome. However, current evidence on the determinants, particularly the modifiable factors of circulating FGF23 levels that increase independently of the kidney function, remains limited. In this study, we aimed to investigate the association between physical performance measures and circulating FGF23 levels in middle-aged and older adults with normal kidney function. This cross-sectional study assessed circulating FGF23 levels and physical performance parameters, including the handgrip strength, knee extension strength, maximal gait speed, the 30-second chair stand test (30s-CST), sit-and-reach test, and aerobic exercise capacity in 158 participants. Multiple regression analyses were performed to evaluate the independent associations between circulating FGF23 levels and physical performance measures after adjusting for potential confounders including age, sex, the presence of lifestyle-related disease, serum phosphate and phosphate-regulating hormone, estimated glomerular filtration rate, and urinary albumin-to-creatinine ratio. Higher circulating FGF23 levels were associated with lower handgrip strength, knee extension strength, maximal gait speed, 30s-CST score, and aerobic exercise capacity. These associations remained significant after adjusting for confounders, except for the association with handgrip strength and aerobic exercise capacity, which was attenuated when renal function variables were included. However, when all physical performance parameters were included in a model, knee extension strength and aerobic exercise capacity were identified as independent determinants of circulating FGF23 levels. Physical performance, particularly knee extension strength, and to a lesser extent aerobic exercise capacity, was independently or partially associated with circulating FGF23 levels in individuals with normal kidney function. Maintaining physical performance may help regulate circulating FGF23 levels, highlighting a potential role in preventing its elevation.

Ginseng, a popular herbal supplement among athletes, is believed to enhance exercise capacity and performance. This study investigated the short-term effects of Panax ginseng extract (PG) on aerobic capacity, lipid profile, and cytokines. In a 14-day randomized, double-blind trial, male participants took 500 mg of PG daily. Two experiments were conducted: one in 10 km races (n = 31) and another in a laboratory-controlled aerobic capacity test (n = 20). Blood lipid and cytokine profile, ventilation, oxygen consumption, hemodynamic and fatigue parameters, and race time were evaluated. PG supplementation led to reduced total blood lipid levels, particularly in triacylglycerides (10 km races −7.5 mg/dL (95% CI −42 to 28); sub-maximal aerobic test −14.2 mg/dL (95% CI −52 to 23)), while post-exercise blood IL-10 levels were increased (10 km 34.0 pg/mL (95% CI −2.1 to 70.1); sub-maximal aerobic test 4.1 pg/mL (95% CI −2.8 to 11.0)), and oxygen consumption decreased during the sub-maximal aerobic test (VO2: −1.4 mL/min/kg (95% CI −5.8 to −0.6)). No significant differences were noted in race time, hemodynamic, or fatigue parameters. Overall, PG supplementation for 2 weeks showed benefits in blood lipid profile and energy consumption during exercise among recreational athletes. This suggests a potential role for PG in enhancing exercise performance and metabolic health in this population.

The \"moderate-to-high-risk\" surgical patient is typically older, frail, malnourished, suffering from multiple comorbidities and presenting with unhealthy life style such as smoking, hazardous drinking and sedentarity. Poor aerobic fitness, sarcopenia and \"toxic\" behaviors are modifiable risk factors for major postoperative complications. The physiological challenge of lung cancer surgery has been likened to running a marathon. Therefore, preoperative patient optimization or \" prehabilitation \" should become a key component of improved recovery pathways to enhance general health and physiological reserve prior to surgery. During the short preoperative period, the patients are more receptive and motivated to adhere to behavioral interventions (e.g., smoking cessation, weaning from alcohol, balanced food intake and active mobilization) and to follow a structured exercise training program. Sufficient protein intake should be ensured (1.5-2 g/kg/day) and nutritional defects should be corrected to restore muscle mass and strength. Currently, there is strong evidence supporting the effectiveness of various modalities of physical training (endurance training and/or respiratory muscle training) to enhance aerobic fitness and to mitigate the risk of pulmonary complications while reducing the hospital length of stay. Multimodal interventions should be individualized to the patient's condition. These bundle of care are more effective than single or sequential intervention owing to synergistic benefits of education, nutritional support and physical training. An effective prehabilitation program is necessarily patient-centred and coordinated among health care professionals (nurses, primary care physician, physiotherapists, nutritionists) to help the patient regain some control over the disease process and improve the physiological reserve to sustain surgical stress.

Introduction and Objectives: Aerobic capacity and muscular strength are two important physical components that influence the performance of middle-distance runners. High-intensity interval Training (HIIT) and unification training have been recognized as effective methods for improving these parameters. However, scientific evidence comprehensively examining the effects of these two methods on middle-distance runners is limited. Therefore, this study aimed to systematically evaluate the impact of HIIT and unification training on the aerobic capacity and muscle strength of middle-distance runners. Methodology: This study was a systematic review that followed the PRISMA guidelines. Data were obtained from PubMed, Scopus, and Google Scholar databases with inclusion criteria including experimental studies published in the last 10 years. A total of 20 articles were selected and analyzed qualitatively. The main parameters evaluated were changes in aerobic capacity (VO₂max) and muscle strength (dynamic and isometric) in middle-distance runners. Results: This review found that HIIT significantly improved aerobic capacity through cardiovascular adaptation and oxygen efficiency. Unification training, which combines aerobic and strength components, showed significant improvements in muscle strength, especially in the lower limb muscles. Several studies have shown that combining HIIT and unification training synergistically affects both parameters. Conclusion: HIIT and unification training improves aerobic capacity and muscular strength in middle-distance runners. The combination of both methods provided more optimal results. The practical implication is that coaches and athletes can adopt an integrated training approach to optimize performance. Further research is needed to explore the most effective exercise duration and intensity.

Highlights The ketogenic diet is widely recognized for its weight loss effects, and this study provides evidence of its effect on muscle, including muscle mass, strength, aerobic metabolic capacity, and endurance. The ketogenic diet does not have adverse effects on muscle mass or muscle strength. The ketogenic diet enhances fat oxidation and reduces respiratory exchange ratio during treadmill tests, indicating a shift in muscle energy metabolism. Background The ketogenic diet (KD) has gained popularity as an efficient approach to weight loss and body fat loss. Concerns about reducing muscle mass and performance have been rising during weight loss, as muscle mass and functionality are crucial for health. However, the effects of the KD on muscles not only for athletes or trainers but also for adults with less physical exercise are still controversial. Methods We conducted a thorough search of databases including Embase, PubMed, Cochrane Library, and Web of Science up to July 19, 2025. Three aspects of muscle assessment were conducted, including muscle mass, power and strength, aerobic metabolic capacity, and endurance. We included randomized and non-randomized controlled studies that compared the KD with other dietary interventions. Studies without control groups were excluded. A random-effects model would be utilized when significant differences in populations and interventions across studies were of concern. The GRADE system was employed to assess evidence quality, while evidence reliability was gauged via sensitivity analysis. Results A total of 33 studies were analyzed, revealing no significant differences between the KD and other diets in muscle mass (WMD: 0.06, 95%CI: -1.97 to 2.09, p  = 0.95), muscle power (countermovement jump: SMD: -0.06, 95%CI: -0.49 to 0.38, p  = 0.80) and strength (squat: SMD: -0.19, 95%CI: -0.53 to 0.15, p  = 0.27; bench press: SMD: -0.15, 95%CI: -0.49 to 0.18, p  = 0.37). However, a significant decrease in fat-free mass (WMD: -0.48, 95%CI: -0.73 to -0.23, p  < 0.001) and fat mass (WMD: -1.31, 95%CI: -2.06 to -0.57, p  < 0.001) was observed in the KD group compared with the control group. The KD also improved fat oxidation (WMD: 0.13, 95%CI: 0.08 to 0.17, p  < 0.001) and reduced respiratory exchange ratio (WMD: -0.07, 95%CI: -0.11 to -0.03, p  < 0.001) during an exercise test. The VO 2max and VO 2max relative to body weight, treadmill time to exhaustion, and rating of perceived exertion were not significantly affected by KD. Conclusions Among adult populations, KD can increase fat oxidation to modify muscle metabolism, while no significant reduction in muscle mass or strength was observed. Additional well-designed randomized controlled trials are warranted to definitively determine the effects of ketogenic diets on muscle parameters.

The aim of the study was to investigate test reliability of the Yo-Yo intermittent recovery test level 1 (YYIR1) in 36 high-level youth soccer players, aged between 13 and 18 years. Players were divided into three age groups (U15, U17 and U19) and completed three YYIR1 in three consecutive weeks. Pairwise comparisons were used to investigate test reliability (for distances and heart rate responses) using technical error (TE), coefficient of variation (CV), intra-class correlation (ICC) and limits of agreement (LOA) with Bland-Altman plots. The mean YYIR1 distances for the U15, U17 and U19 groups were 2024 ± 470 m, 2404 ± 347 m and 2547 ± 337 m, respectively. The results revealed that the TEs varied between 74 and 172 m, CVs between 3.0 and 7.5%, and ICCs between 0.87 and 0.95 across all age groups for the YYIR1 distance. For heart rate responses, the TEs varied between 1 and 6 bpm, CVs between 0.7 and 4.8%, and ICCs between 0.73 and 0.97. The small ratio LOA revealed that any two YYIR1 performances in one week will not differ by more than 9 to 28% due to measurement error. In summary, the YYIR1 performance and the physiological responses have proven to be highly reliable in a sample of Belgian high-level youth soccer players, aged between 13 and 18 years. The demonstrated high level of intermittent endurance capacity in all age groups may be used for comparison of other prospective young soccer players.

Although the relationship between protein-bound uremic toxins (PBUTs) and cardiac structure and cardiac mortality in chronic kidney disease (CKD) has been studied in the past, the association between cardiac dysfunction and PBUTs has not yet been studied. We therefore evaluated the association between impaired peak cardiac performance and the serum free and total concentrations of potentially cardiotoxic PBUTs. In a cross-sectional study of 56 male CKD patients (stages 2–5 (pre-dialysis)) who were asymptomatic with no known cardiac diseases or diabetes we measured peak cardiac power (CPOmax), aerobic exercise capacity (VO2max), and echocardiographic parameters of cardiac morphology and evaluated their association with PBUTs. The serum total and free concentrations of indoxyl sulfate (IXS), p-cresyl sulfate (PCS), p-cresyl glucuronide, indole acetic acid, and hippuric acid showed significant negative correlation with CPOmax and VO2max. IXS and PCS were independently associated with CPOmax and VO2max even after controlling for eGFR. No correlation between left ventricular mass index (LVMI) and PBUTs was seen. The present study for the first time has demonstrated the association between subclinical cardiac dysfunction in CKD and serum levels of a panel of PBUTs. Further studies are required to evaluate the mechanism of cardiotoxicity of the individual uremic toxins.

Please see the corrected Table 2 here: thumbnail Download: * PPT PowerPoint slide * PNG larger image * TIFF original image Figures Citation: Loe H, Rognmo Ø, Saltin B, Wisløff U (2013) Correction: Aerobic Capacity Reference Data in 3816 Healthy Men and Women 20–90 Years. No competing interests declared.