The "Aging Effect" of BMI on Cardiorespiratory Fitness: A New Insight on Functional Evaluation in Obesity

Cardiorespiratory fitness (CRF) is a strong predictor of morbidity and mortality in patients with obesity. This study investigates the CRF range and its clinical determinants in patients with obesity. Moreover, a practical proposal for CRF interpretation is provided. In this study, 542 patients (69% females) with BMI ≥ 30 kg/m2 performed an incremental cardiopulmonary exercise test (CPET). Patients had a median (IQR) age of 47.0 (6.2) years with a mean BMI of 41.7 ± 6.7 kg/m2. Normal values curves of VO2peak/kg showed a median (IQR) of 20.3 (37.6) mL/min/kg. The lower-quartile threshold of VO2peak/kg was at 17.9 mL/min/kg. Analysis of covariance revealed that VO2peak/kg inversely correlates with age and BMI with a significant age × BMI interaction effect (all p < 0.0001); as BMI class increases, CRF decreases, but a smaller age-related decline in VO2peak/kg is observed. A multivariate logistic regression demonstrated that belonging to the lower quartile of VO2peak/kg was independently determined by age (OR 2.549, 95% CI 1.205-5.392, p < 0.0001) and BMI (OR 5.864, 95% CI 2.920-11.778, p < 0.0001) but not by comorbidities. At very high BMI, the effect of age on functional capacity is lower, suggesting that BMI acts as an "aging factor" on CRF. Age and BMI, but not comorbidities, are independent determinants of low VO2peak/kg.

Cardiopulmonary exercise testing predicts prognosis in amyloid cardiomyopathy: a systematic review and meta-analysis

BACKGROUND

The clinical value of cardiopulmonary exercise testing (CPET) in cardiac amyloidosis (CA) is uncertain. Due to the growing prevalence of the disease and the current availability of disease-modifying drugs, prognostic stratification is becoming fundamental to optimizing the cost-effectiveness of treatment, patient phenotyping, follow-up, and management. Peak VO₂ and VE/VCO₂ slope are currently the most studied CPET variables in clinical settings, and both demonstrate substantial, independent prognostic value in several cardiovascular diseases. We aim to study the association of peak VO₂ and VE/VCO₂ slope with prognosis in patients with CA.

METHODS AND RESULTS

We performed a systematic review and searched for clinical studies performing CPET for prognostication in patients with transthyretin-CA and light-chain-CA. Studies reporting hazard ratio (HR) for mortality and peak VO₂ or VE/VCO₂ slope were further selected for quantitative analysis. HRs were pooled using a random-effect model. Five studies were selected for qualitative and three for quantitative analysis. A total of 233 patients were included in the meta-analysis. Mean peak VO₂ resulted consistently depressed, and VE/VCO₂ slope was increased. Our pooled analysis showed peak VO₂ (pooled HR 0.89, 95% CI 0.84-0.94) and VE/VCO₂ slope (pooled HR 1.04, 95% CI 1.01-1.07) were significantly associated with the risk of death in CA patients, with no significant statistical heterogeneity for both analyses.

CONCLUSIONS

CPET is a valuable tool for prognostic stratification in CA, identifying patients at increased risk of death. Large prospective clinical trials are needed to confirm this exploratory finding.

Is the Verification Phase a Suitable Criterion for the Determination of Maximum Oxygen Uptake in Patients with Heart Failure and Reduced Ejection Fraction? A Validation Study

The verification phase (VP) has been proposed as an alternative to the traditional criteria used for the determination of the maximum oxygen uptake (VO2 max) in several populations. Nonetheless, its validity in patients with heart failure with reduced ejection fraction (HFrEF) remains unclear. Therefore, the aim of this study was to analyse whether the VP is a safe and suitable method to determine the VO2 max in patients with HFrEF. Adult male and female patients with HFrEF performed a ramp-incremental phase (IP), followed by a submaximal constant VP (i.e., 95% of the maximal workload during the IP) on a cycle ergometer. A 5-min active recovery period (i.e., 10 W) was performed between the two exercise phases. Group (i.e., median values) and individual comparisons were performed. VO2 max was confirmed when there was a difference of ≤ 3% in peak oxygen uptake (VO2 peak) values between the two exercise phases. Twenty-one patients (13 males) were finally included. There were no adverse events during the VP. Group comparisons showed no differences in the absolute and relative VO2 peak values between both exercise phases (p = 0.557 and p = 0.400, respectively). The results did not change when only male or female patients were included. In contrast, individual comparisons showed that the VO2 max was confirmed in 11 patients (52.4%) and not confirmed in 10 (47.6%). The submaximal VP is a safe and suitable method for the determination of the VO2 max in patients with HFrEF. In addition, an individual approach should be used because group comparisons could mask individual differences.

The impact of statin therapy and aerobic exercise training on skeletal muscle and whole-body aerobic capacity

Background

Statin use is widely recognized for improving cardiovascular health, but questions remain on how statin use influences skeletal muscle, particularly mitochondrial function.

Study objective design and participants

The influence of statin therapy and exercise (EX) on aerobic capacity was determined. In Study1, skeletal muscle aerobic capacity was measured before and after 80 mg atorvastatin therapy. In Study2, aerobic capacity (skeletal muscle and whole body) was measured before and after a 12-week exercise randomized control trial in older adults (age = 67 ± 5 yrs.), a subset of which were on chronic low-moderate intensity statin therapy.

Main outcome measures

Muscle oxidative capacity was determined from the phosphocreatine recovery rate constant (kPCr) using ³¹P Magnetic Resonance Spectroscopy. Whole body peak oxygen uptake (VO₂ peak) was measured during a graded exercise test with indirect calorimetry.

Results

High dose statin therapy resulted in a 12% reduction in muscle oxidative capacity (pre = 1.34 ± 0.34 min^-1, post = 1.17 ± 0.25 min^-1, p = 0.004). Similarly, chronic low-moderate dose statin therapy was associated with lower muscle oxidative capacity at baseline (1.50 ± 0.35 min^-1) compared to non-statin users (1.88 ± 0.047 min^-1, p = 0.019). Following EX, muscle oxidative capacity increased by 35-40% (statin: Pre: 1.39 ± 0.44 vs. Post: 1.88 ± 0.47 min^-1, no statin Pre: 1.86 ± 0.58 vs. Post: 2.58 ± 0.85 min^-1) compared to control groups (Pre: 1.74 ± 0.27 vs Post: 1.75 ± 0.49 min^-1, p = 0.001). VO₂ peak increased by 11% for EX groups (Pre: 18.8 ± 2.8 vs. Post: 20.8 ± 3.0 ml·kg^-1·min^-1) following training compared to a small decline in controls (Pre: 21.8 ± 3.7 vs. Post: 20.8 ± 3.04 ml·kg^-1·min^-1, p = 0.001).

Conclusions

Statin therapy resulted in reduced muscle oxidative capacity. Aerobic exercise improved skeletal muscle oxidative capacity and whole-body aerobic capacity during statin therapy.

Comparing Idiopathic Chronic Fatigue and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) in Males: Response to Two-Day Cardiopulmonary Exercise Testing Protocol

(1) Introduction: Multiple studies have shown that peak oxygen consumption is reduced in the majority of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS )patients, using the gold standard for measuring exercise intolerance: cardiopulmonary exercise testing (CPET). A 2-day CPET protocol has shown different results on day 2 in ME/CFS patients compared to sedentary controls. No comparison is known between ME/CFS and idiopathic chronic fatigue (ICF) for 2-day CPET protocols. We compared ME/CFS patients with patients with chronic fatigue who did not fulfill the ME/CFS criteria in a male population and hypothesized a different pattern of response would be present during the 2nd day CPET. (2) Methods: We compared 25 male patients with ICF who had completed a 2-day CPET protocol to an age-/gender-matched group of 26 male ME/CFS patients. Measures of oxygen consumption (VO₂), heart rate (HR), systolic and diastolic blood pressure, workload (Work), and respiratory exchange ratio (RER) were collected at maximal (peak) and ventilatory threshold (VT) intensities. (3) Results: Baseline characteristics for both groups were similar for age, body mass index (BMI), body surface area, (BSA), and disease duration. A significant difference was present in the number of patients with fibromyalgia (seven ME/CFS patients vs. zero ICF patients). Heart rate at rest and the RER did not differ significantly between CPET 1 and CPET 2. All other CPET parameters at the ventilatory threshold and maximum exercise differed significantly (p-value between 0.002 and <0.0001). ME/CFS patients showed a deterioration of performance on CPET2 as reflected by VO₂ and workload at peak exercise and ventilatory threshold, whereas ICF patients showed improved performance on CPET2 with no significant change in peak workload. (4) Conclusion: This study confirms that male ME/CFS patients have a reduction in exercise capacity in response to a second-day CPET. These results are similar to published results in male ME/CFS populations. Patients diagnosed with ICF show a different response on day 2, more similar to sedentary and healthy controls.

Female Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome or Idiopathic Chronic Fatigue: Comparison of Responses to a Two-Day Cardiopulmonary Exercise Testing Protocol

Introduction: Multiple studies have shown that peak oxygen consumption is reduced in the majority of ME/CFS patients, using the golden standard for measuring exercise intolerance: cardiopulmonary exercise testing (CPET). A 2-day CPET protocol has shown different results on day 2 in ME/CFS patients compared to sedentary controls. No comparison is known between ME/CFS and idiopathic chronic fatigue (ICF) for 2-day CPET protocols. We compared ME/CFS patients with patients with chronic fatigue who did not fulfil the ME/CFS criteria in a male population and hypothesized a different pattern of response would be present during the 2nd day CPET. Methods: Fifty-one female patients with ICF completed a 2-day CPET protocol and were compared to an age/sex-matched group of 50 female ME/CFS patients. Measures of oxygen consumption (VO₂), heart rate (HR), systolic and diastolic blood pressure, workload (Work), and respiratory exchange ratio (RER) were collected at maximal (peak) and ventilatory threshold (VT) intensities. Results: Baseline characteristics for both groups were similar for age, BMI, BSA, and disease duration. A significance difference was present in the number of patients with fibromyalgia (seven ME/CFS patients vs zero ICF patients). Heart rate at rest and the RER did not differ significantly between CPET 1 and CPET 2. All other CPET parameters at the ventilatory threshold and maximum exercise differed significantly (p-value between 0.002 and <0.0001). ME/CFS patients showed a deterioration of performance on CPET2 as reflected by VO₂ and workload at peak exercise and ventilatory threshold, whereas ICF patients showed improved performance on CPET2 with no significant change in peak workload. Conclusion: This study confirms that female ME/CFS patients have a reduction in exercise capacity in response to a second day CPET. These results are similar to published results in female ME/CFS populations. Patients diagnosed with ICF show a different response on day 2, more similar to sedentary and healthy controls.

Blood Volume, Hemoglobin Mass, and Peak Oxygen Uptake in Older Adults: The Generation 100 Study

Purpose: To investigate the association between blood volume, hemoglobin mass (Hb_mass), and peak oxygen uptake (VO_2peak) in healthy older adults.

Methods: Fifty fit or unfit participants from the prospective randomized Generation 100 Study (n = 1,566) were included (age- and sex-specific VO_2peak above or below average values). Blood, plasma, and erythrocyte volume and Hb_mass were tested using the carbon monoxide rebreathing method within 1 week after VO_2peak testing.

Results: Mean age, BMI, Hb_mass, blood volume, and VO_2peak were 73.0 ± 2.1 years, 24.8 ± 3.3 kg·m², 10.0 ± 1.7 g·kg⁻¹, 76.4 ± 11.8 mL·kg⁻¹, and 33.5 ± 8.4 mL·kg⁻¹·min⁻¹. VO_2peak in fit and unfit participants and women and men were 38.6 ± 6.5 and 25.8 ± 3.8 mL·kg⁻¹·min⁻¹, 30.7 ± 7.6 mL·kg⁻¹·min⁻¹, and 35.5 ± 8.5 mL·kg⁻¹·min⁻¹, respectively. Women were shorter (Δ14 cm), leaner (Δ13 kg), and with less muscle mass (Δ9%) than men (P < 0.05). Relative erythrocyte volume and Hb_mass were lower in women, and blood and erythrocyte volume and Hb_mass were higher in the fit participants (P < 0.05). Hb_mass and erythrocyte volume explained 40 and 37%, respectively, of the variability in VO_2peak, with a limited effect of physical-activity adjustment (40 and 38%, respectively). Blood and plasma volume explained 15 and 25%, respectively, of VO_2peak variability, and the association was strengthened adjusting for physical activity (25 and 31%, respectively), indicating a training-dependent adaptation in plasma but not erythrocyte volume (p ≤ 0.006).

Conclusions: Blood and plasma volumes were moderately associated with VO_2peak in healthy older men and women, and the association was strengthened after adjustment for physical activity. Hb_mass and erythrocyte volume were strongly associated with VO_2peak but unrelated to physical activity.

Response of Mitochondrial Respiration in Adipose Tissue and Muscle to 8 Weeks of Endurance Exercise in Obese Subjects

CONTEXT

Exercise training improves glycemic control and increases mitochondrial content and respiration capacity in skeletal muscle. Rodent studies suggest that training increases mitochondrial respiration in adipose tissue.

OBJECTIVE

To assess the effects of endurance training on respiratory capacities of human skeletal muscle and abdominal subcutaneous adipose tissue and to study the correlation with improvement in insulin sensitivity.

DESIGN

Using high-resolution respirometry, we analyzed biopsies from 25 sedentary (VO2 peak 25.1 ± 4.0 VO2 mL/[kg*min]) subjects (16 female, 9 male; 29.8 ± 8.4 years) with obesity (body mass index [BMI] 31.5 ± 4.3 kg/m2), who did not have diabetes. They performed a supervised endurance training over 8 weeks (3 × 1 hour/week at 80% VO2 peak).

RESULTS

Based on change in insulin sensitivity after intervention (using the Matsuda insulin sensitivity index [ISIMats]), subjects were grouped in subgroups as responders (>15% increase in ISIMats) and low-responders. The response in ISIMats was correlated to a reduction of subcutaneous and visceral adipose tissue volume. Both groups exhibited similar increases in fitness, respiratory capacity, and abundance of mitochondrial enzymes in skeletal muscle fibers. Respiratory capacities in subcutaneous adipose tissue were not altered by the intervention. Compared with muscle fibers, adipose tissue respiration showed a preference for β-oxidation and complex II substrates. Respiratory capacities were higher in adipose tissue from female participants.

CONCLUSION

Our data show that the improvement of peripheral insulin sensitivity after endurance training is not directly related to an increase in mitochondrial respiratory capacities in skeletal muscle and occurs without an increase in the respiratory capacity of subcutaneous adipose tissue.

Interrelationship of physical exercise, perceptual discrimination and academic achievement variables in high school students

BACKGROUND

Many studies results suggest how can we improve the academic performance for our kids. The purposes of this study were to examine how physical activity could affect both academic achievement and fluid intelligence in adolescence.

STUDY DESIGN

We measured the three variables (physical, cognitive, academic) and try to find the correlations between them.

METHODS

A total of 167 adolescents (mean age = 16.34 years SD = 1.2) from Morocco are participating in this study. The cardiorespiratory fitness was measured with the20 m endurance shuttle-run test. We also assessed the Resistance capacity with 500m sprint test. The academic achievement was assessed by school grades. The fluid intelligence was assessed by using Raven's Standard Progressive Matrices. We examined the correlation between all variables.

RESULTS

This study indicates that the academic achievement was positively associated with the Fluid Intelligence and also with the Resistance Capacity and not with Cardiorespiratory Fitness (VO2peak).

CONCLUSIONS

We can conclude that the professionals and researchers in sports and education have to promote physical activity at the school age for a public health purpose.

Two-Day Cardiopulmonary Exercise Testing in Females with a Severe Grade of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Comparison with Patients with Mild and Moderate Disease

Introduction: Effort intolerance along with a prolonged recovery from exercise and post-exertional exacerbation of symptoms are characteristic features of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The gold standard to measure the degree of physical activity intolerance is cardiopulmonary exercise testing (CPET). Multiple studies have shown that peak oxygen consumption is reduced in the majority of ME/CFS patients, and that a 2-day CPET protocol further discriminates between ME/CFS patients and sedentary controls. Limited information is present on ME/CFS patients with a severe form of the disease. Therefore, the aim of this study was to compare the effects of a 2-day CPET protocol in female ME/CFS patients with a severe grade of the disease to mildly and moderately affected ME/CFS patients. Methods and results: We studied 82 female patients who had undergone a 2-day CPET protocol. Measures of oxygen consumption (VO₂), heart rate (HR) and workload both at peak exercise and at the ventilatory threshold (VT) were collected. ME/CFS disease severity was graded according to the International Consensus Criteria. Thirty-one patients were clinically graded as having mild disease, 31 with moderate and 20 with severe disease. Baseline characteristics did not differ between the 3 groups. Within each severity group, all analyzed CPET parameters (peak VO₂, VO₂ at VT, peak workload and the workload at VT) decreased significantly from day-1 to day-2 (p-Value between 0.003 and <0.0001). The magnitude of the change in CPET parameters from day-1 to day-2 was similar between mild, moderate, and severe groups, except for the difference in peak workload between mild and severe patients (p = 0.019). The peak workload decreases from day-1 to day-2 was largest in the severe ME/CFS group (−19 (11) %). Conclusion: This relatively large 2-day CPET protocol study confirms previous findings of the reduction of various exercise variables in ME/CFS patients on day-2 testing. This is the first study to demonstrate that disease severity negatively influences exercise capacity in female ME/CFS patients. Finally, this study shows that the deterioration in peak workload from day-1 to day-2 is largest in the severe ME/CFS patient group.

The Relationship of VO2 Peak and the Blood Lactate Transition Threshold with Metabolic Syndrome and Its Component Disorders

Background: Improvements in cardiorespiratory fitness attenuate the risk for metabolic syndrome (MetS). However, the determinants of cardiorespiratory fitness measurements such as oxygen consumption (VO₂) peak and anaerobic threshold (AT) have not been investigated in persons with MetS. Therefore, the main aim of this study was to compare VO₂ peak and AT between subjects with and without MetS and to investigate determinants of cardiorespiratory fitness and its effects on the odds for MetS and its individual components. Methods: Thirty-one males with MetS and 24 healthy male participants each performed a VO₂ peak and a blood lactate transition threshold test. Waist circumference, body mass index (BMI), blood pressure, fasting plasma triglyceride, total cholesterol, high-density lipoprotein cholesterol, glucose, and insulin levels were measured. Separate multivariable linear regression models were developed in which VO₂ peak, AT, and the components of MetS were used as the dependent variables, while a multivariable logistic regression model was used for MetS. Results: The VO₂ peak [median (interquartile range)] was lower in subjects with MetS compared with controls [27.9 (23.0-31.0) vs. 35.0 (32.0-45.0) mL·min^-1·kg^-1; P < 0.0001]. Multivariable regression analysis demonstrated that there was a bidirectional association between MetS and VO₂ peak that was mediated by waist circumference and blood pressure. The VO₂ peak was a strong negative determinant of waist circumference (β = -0.36, P < 0.0001), but not of BMI (β = -0.13, P = 0.21). Conclusions: A higher VO₂ peak is associated with a lower odds ratio for MetS, which is related to greater cardiorespiratory fitness in a cyclical relationship that is mediated by blood pressure and waist circumference. A higher VO₂ peak is specifically associated with lower waist circumference, and vice versa, possibly by effects on visceral fat.

Multi-Stage Fitness Test Performance, V ˙ O2 Peak and Adiposity: Effect on Risk Factors for Cardio-Metabolic Disease in Adolescents

The role of physical activity in determining the metabolic health of adolescents is poorly understood, particularly concerning the effect on low-grade chronic inflammation (chronic elevation of pro-inflammatory cytokines IL-1β, IL-6, TNF-α and acute phase protein CRP, which is implicated in the etiology of atherosclerosis) and anti-inflammatory mediators such as IL-10. Furthermore, there is limited information on the mediating effects of performance on the multi-stage fitness test (MSFT), V˙O₂ peak and adiposity on risk factors for cardio-metabolic disease in adolescents.

Purpose: To examine the effect of performance on the MSFT, V˙O₂ peak and adiposity on risk factors for cardio-metabolic diseases in adolescents.

Methods: Following ethical approval, 121 adolescents (11.3 ± 0.8 year) completed the study. Risk factors for cardio-metabolic disease (circulating inflammatory cytokines, blood glucose and plasma insulin concentrations) was assessed using a fasted capillary blood sample. Participants were separated into quartiles based upon distance ran during the MSFT, the blood lactate response to submaximal exercise, V˙O₂ peak (determined during an uphill graded treadmill test), and adiposity (determined as the sum of four skinfolds). The blood lactate response to submaximal exercise and V0₂ peak were measured in a sub-group of participants. Data were analyzed using two-way between-subjects ANCOVA and multiple linear regression.

Results: Participants with the lowest performance on the MSFT had higher blood concentrations of IL-6 (3.25 ± 0.25 pg mL^-1) and IL-1β (4.78 ± 0.54 pg mL^-1) and lower concentrations of IL-10 (1.80 ± 0.27 pg mL^-1) when compared with all other quartiles (all p < 0.05). Yet, when categorized into V˙O₂ peak quartiles, no differences existed in any of the inflammatory mediators (all p > 0.05). Performance on the MSFT was the only predictor of IL-6 (β = -0.291, p = 0.031), IL-1β (β = -0.405, p = 0.005), IL-10 (β = 0.325, p = 0.021) and fasted blood glucose (β = -0.545, p < 0.001) concentrations. Adiposity was the only predictor of plasma insulin concentration (β = 0.515, p < 0.001) and blood pressure (diastolic: β = 0.259, p = 0.042; mean arterial pressure: β = 0.322, p = 0.011).

Conclusion: Enhanced performance on the MSFT, but not V˙O₂ peak, was associated with a favorable inflammatory profile in adolescents; whilst adiposity adversely affected plasma insulin, diastolic and mean arterial blood pressure. These findings demonstrate that enhancing performance on the MSFT and maintaining a healthy body composition are a potential therapeutic intervention for the attenuation of risk factors for cardio-metabolic diseases in adolescents.

Impact of preoperative exercise therapy on surgical outcomes in lung cancer patients with or without COPD: a systematic review and meta-analysis

Objectives

This meta-analysis aimed to demonstrate the impact of preoperative exercise therapy on surgical outcomes in patients with lung cancer and COPD. Pulmonary function and muscle capacity were investigated to explore their potential links with outcome improvements after exercise.

Methods

Articles were searched from PubMed, Embase, and the Cochrane Library with criteria of lung cancer patients with or without COPD, undergoing resection, and receiving preoperative exercise training. Key outcomes were analyzed using meta-analysis.

Results

Seven studies containing 404 participants were included. Patients receiving preoperative exercise training had a lower incidence of postoperative pulmonary complications (PPCs; OR 0.44, 95% CI 0.27-0.71) and shorter length of hospital stay (standardized mean difference -4.23 days, 95% CI -6.14 to -2.32 days). Exceptionally, pneumonia incidence remained unchanged. Patients with COPD could not obviously benefit from exercise training to reduce PPCs (OR 0.44, 95% CI 0.18-1.08), but still might achieve faster recovery. No significant difference in pulmonary function was observed between the two groups. However, 6MWD and VO₂ peak were significantly improved after exercise training.

Conclusion

Preoperative exercise training may reduce PPCs for lung cancer patients. However, for patients with COPD undergoing lung cancer resection, the role of exercise is uncertain, due to limited data, which calls for more prospective trials on this topic. Rehabilitation exercise strengthens muscle capacity, but does not improve impaired pulmonary function, which emphasizes the possible mechanism of the protocol design.

Neither Hematocrit Normalization nor Exercise Training Restores Oxygen Consumption to Normal Levels in Hemodialysis Patients

Patients treated with hemodialysis develop severely reduced functional capacity, which can be partially ameliorated by correcting anemia and through exercise training. In this study, we determined perturbations of an erythroid-stimulating agent and exercise training to examine if and where limitation to oxygen transport exists in patients on hemodialysis. Twenty-seven patients on hemodialysis completed a crossover study consisting of two exercise training phases at two hematocrit (Hct) values: 30% (anemic) and 42% (physiologic; normalized by treatment with erythroid-stimulating agent). To determine primary outcome measures of peak power and oxygen consumption (VO₂) and secondary measures related to components of oxygen transport and utilization, all patients underwent numerous tests at five time points: baseline, untrained at Hct of 30%, after training at Hct of 30%, untrained at Hct of 42%, and after training at Hct of 42%. Hct normalization, exercise training, or the combination thereof significantly improved peak power and VO₂ relative to values in the untrained anemic phase. Hct normalization increased peak arterial oxygen and arteriovenous oxygen difference, whereas exercise training improved cardiac output, citrate synthase activity, and peak tissue diffusing capacity. However, although the increase in arterial oxygen observed in the combination phase reached a value similar to that in healthy sedentary controls, the increase in peak arteriovenous oxygen difference did not. Muscle biopsy specimens showed markedly thickened endothelium and electron-dense interstitial deposits. In conclusion, exercise and Hct normalization had positive effects but failed to normalize exercise capacity in patients on hemodialysis. This effect may be caused by abnormalities identified within skeletal muscle.

Effects of high intensity training and continuous endurance training on aerobic capacity and body composition in recreationally active runners

The aim of the study was to examine the effects of two different training programs (high-intensity-training vs. continuous endurance training) on aerobic power and body composition in recreationally active men and women and to test whether or not participants were able to complete a half marathon after the intervention period. Thirty-four recreational endurance runners were randomly assigned either to a Weekend-Group (WE, n = 17) or an After-Work- Group (AW, n = 17) for a 12 week-intervention period. WE weekly completed 2 h 30 min of continuous endurance running composed of 2 sessions on the weekend. In contrast, AW performed 4 30 min sessions of high intensity training and an additional 30 min endurance run weekly, always after work. During an exhaustive treadmill test aerobic power was measured and heart rate was continuously recorded. Body composition was assessed using bio-impedance. Following the intervention period all subjects took part in a half-marathon. AW significantly improved peak oxygen uptake (VO2 peak) from 36.8 ± 4.5 to 43.6 ± 6.5 [mL.min(-1).kg(-1)], velocity at lactate threshold (VLT) from 9.7 ± 2.2 to 11.7 ± 1.8 [km.h(-1)] and visceral fat from 5.6 ± 2.2 to 4.7 ± 1.9 In WE VO2 peak signifi-cantly increased from 38.8 ± 5.0 to 41.5 ± 6.0 [mL.min(-1).kg(-1)], VLT from 9.9 ± 1.3 to 11.2 ± 1.7 [km.h(-1)] and visceral fat was reduced from 5.7 ± 2.1 to 5.4 ± 1.9 (p < 0.01). Only the improvements of VO2 peak were significantly greater in AW compared with WE (pre/post group interaction: F=15.4, p = 0.01, η(2) = 0.36). Both groups completed a half marathon with no significant differences in performance (p = 0.63). Short, intensive endurance training sessions of about 30 min are effective in improving aerobic fitness in recreationally active runners. Key pointsContinuous endurance training and high intensity training lead to significant improvements of aerobic capacity and body compositionBoth training methods enable recreationally active runners to finish a half-marathonHigh intensity training is favorable to improve VO2 peak.

Association between sarcopenia-related phenotypes and aerobic capacity indexes of older women

The purpose of the present study was to examine the association between fat-free mass (FFM), quadriceps strength and sarcopenia with aerobic fitness indexes of elderly women. A total of 189 volunteers (66.7 ± 5.46 years) underwent aerobic capacity measurement through a symptom-limited cardiopulmonary exercise test to determine their individual ventilatory thresholds (VT) and peak oxygen uptake (VO2 peak). Quadriceps muscle strength was assessed using an isokinetic dynamometer. Also, dual energy X-ray absorptiometry was used to assess FFM and cutoff values were used to classify subjects as sarcopenic or nonsarcopenic. Correlations, student t-test and analysis of variance were used to examine the data. Both FFM and quadriceps strength variables were positively and significantly correlated with the measured aerobic capacity indexes. These results were observed for peak exercise as well as for ventilatory thresholds. Individuals classified as sarcopenic presented significantly lower muscle strength and (VO2 peak) when compared to nonsarcopenic. It can be concluded that FFM and quadriceps strength are significantly related to aerobic capacity indexes in older women, and that besides presenting lower quadriceps strength, women classified as sarcopenic have lower peak oxygen consumption. Taken together, the present results indicate that both FFM and strength play a role in the age-related decline of aerobic capacity. Key pointsMaximal aerobic capacity, generally expressed as peak oxygen consumption (VO2 peak), declines with advancing age and this process is associated with an increased risk for cardiovascular diseases.Also, the aging process is associated with a progressive loss of muscle mass and strength and this phenomenon has been referred to as Sarcopenia. Sarcopenia has been described in both elderly men and women and has been linked to multiple negative clinical outcomes.The present study provide evidence that muscle-related phenotypes are associated with aerobic capacity of older individuals, thus suggesting that sarcopenia explains in part the decline in aerobic fitness observed with advancing age.