Maximal Exercise Capacity Research Articles

Impacts of Respiratory Muscle Training on Respiratory Functions, Maximal Exercise Capacity, Functional Performance, and Quality of Life in School-Aged Children with Postoperative Congenital Diaphragmatic Hernia.

Objectives Congenital diaphragmatic hernia (CDH) is a birth defect affecting the respiratory functions, functional performance, and quality of life (QOL) in school-aged children. Rarely have studies been conducted to evaluate the impacts of respiratory muscle training on school-aged children with postoperative CDH. The current study was designed to evaluate the impacts of respiratory muscle training on respiratory function, maximal exercise capacity, functional performance, and QOL in these children. Methods This study is a randomized control study. 40 children with CDH (age: 9-11 years) were assigned randomly into two groups. The first group conducted an incentive spirometer exercise combined with inspiratory muscle training (study group, n = 20), whereas the second group conducted only incentive spirometer exercise (control group, n = 20), thrice weekly for twelve consecutive weeks. Respiratory functions, maximal exercise capacity, functional performance, and pediatric quality of life inventory (PedsQL) were assessed before and after the treatment program. Results. Regarding the posttreatment analysis, the study group showed significant improvements in all outcome measures (FVC%, p < 0.001; FEV1%, p = 0.002; VO2max, p = 0.008; VE/VCO2 slope, p = 0.002; 6-MWT, p < 0.001; and PedsQL, p < 0.001), whereas the control group did not show significant changes (p > 0.05). Conclusion Respiratory muscle training may improve respiratory functions, maximal exercise capacities, functional performance, and QOL in children with postoperative CDH. Clinical commendations have to be considered to include respiratory muscle training in pulmonary rehabilitation programs in children with a history of CDH.

Moderate Exercise in Spontaneously Hypertensive Rats Is Unable to Activate the Expression of Genes Linked to Mitochondrial Dynamics and Biogenesis in Cardiomyocytes.

Hypertension (HTN) is a public health concern and a major preventable cause of cardiovascular disease (CVD). When uncontrolled, HTN may lead to adverse cardiac remodeling, left ventricular hypertrophy, and ultimately, heart failure. Regular aerobic exercise training exhibits blood pressure protective effects, improves myocardial function, and may reverse pathologic cardiac hypertrophy. These beneficial effects depend at least partially on improved mitochondrial function, decreased oxidative stress, endothelial dysfunction, and apoptotic cell death, which supports the general recommendation of moderate exercise in CVD patients. However, most of these mechanisms have been described on healthy individuals; the effect of moderate exercise on HTN subjects at a cellular level remain largely unknown. We hypothesized that hypertension in adult spontaneously hypertensive rats (SHRs) reduces the mitochondrial response to moderate exercise in the myocardium.Methods: Eight-month-old SHRs and their normotensive control—Wistar-Kyoto rats (WKYR)—were randomly assigned to moderate exercise on a treadmill five times per week with a running speed set at 10 m/min and 15° inclination. The duration of each session was 45 min with a relative intensity of 70–85% of the maximum O2 consumption for a total of 8 weeks. A control group of untrained animals was maintained in their cages with short sessions of 10 min at 10 m/min two times per week to maintain them accustomed to the treadmill. After completing the exercise protocol, we assessed maximum exercise capacity and echocardiographic parameters. Animals were euthanized, and heart and muscle tissue were harvested for protein determinations and gene expression analysis. Measurements were compared using a nonparametric ANOVA (Kruskal-Wallis), with post-hoc Dunn's test.Results: At baseline, SHR presented myocardial remodeling evidenced by left ventricular hypertrophy (interventricular septum 2.08 ± 0.07 vs. 1.62 ± 0.08 mm, p < 0.001), enlarged left atria (0.62 ± 0.1 mm vs. 0.52 ± 0.1, p = 0.04), and impaired diastolic function (E/A ratio 2.43 ± 0.1 vs. 1.56 ± 0.2) when compared to WKYR. Moderate exercise did not induce changes in ventricular remodeling but improved diastolic filling pattern (E/A ratio 2.43 ± 0.1 in untrained SHR vs. 1.89 ± 0.16 trained SHR, p < 0.01). Histological analysis revealed increased myocyte transversal section area, increased Myh7 (myosin heavy chain 7) expression, and collagen fiber accumulation in SHR-control hearts. While the exercise protocol did not modify cardiac size, there was a significant reduction of cardiomyocyte size in the SHR-exercise group. Conversely, titin expression increased only WYK-exercise animals but remained unchanged in the SHR-exercise group. Mitochondrial response to exercise also diverged between SHR and WYKR: while moderate exercise showed an apparent increase in mRNA levels of Ppargc1α, Opa1, Mfn2, Mff, and Drp1 in WYKR, mitochondrial dynamics proteins remained unchanged in response to exercise in SHR. This finding was further confirmed by decreased levels of MFN2 and OPA1 in SHR at baseline and increased OPA1 processing in response to exercise in heart. In summary, aerobic exercise improves diastolic parameters in SHR but fails to activate the cardiomyocyte mitochondrial adaptive response observed in healthy individuals. This finding may explain the discrepancies on the effect of exercise in clinical settings and evidence of the need to further refine our understanding of the molecular response to physical activity in HTN subjects.

Comparative study of physiologic characteristics between the newly compiled Bafa Wubu of tai chi and 24 form simplified tai chi

BackgroundThe newly compiled Bafa Wubu of Tai Chi (Eight Methods and Five Footworks) is a fitness routine that has been developed in accordance with the appeal of the General Administration of Sport of China and promoted both in China and abroad. This paper aims to compare the differences in energy consumption and related parameters between the two types of Tai Chi.MethodsA total of 60 healthy participants were recruited; 37 males (aged 37.4 ± 10.4 years) and 23 females (aged 31.9 ± 12.8 years). The maximal exercise capacity of participants was measured at baseline. Then, they received Tai Chi training for 12-week and their energy metabolism was measured dynamically.ResultsA set of the Bafa Wubu of Tai Chi requires approximately 3 min, while a set of 24 form simplified Tai Chi approximately 5 min and 40 s. The average oxygen uptake/kg (VO2/kg, 10.8 ± 2.52 ml/kg/min vs. 12.9 ± 2.59 ml/kg/min, P = 0.000), the highest VO2/kg (19.3 ± 6.03 ml/kg/min vs. 24.1 ± 7.50 ml/kg/min, p = 0.000, the average metabolic equivalent (METs,2.3 ± 0.16 METs vs. 3.2 ± 0.14 METs, p = 0.000), the highest oxygen pulse (VO2/HR, 11.1 ± 0.99 ml vs. 13.9 ± 0.93 ml, p = 0.000) and rate of perceived exertion (RPE, 10.7 ± 0.70 vs. 1.3 ± 0.62, p = 0.000) gained immediately after Bafa Wubu of Tai Chi exercise were significantly lower than those in 24 form simplified Tai Chi; heart rate recovery (HRR,1.5 ± 0.41 vs. 1.3 ± 0.45, p = 0.008) at 1 min after the practice was significantly higher than after the 24 form simplified Tai Chi. Meanwhile, the average heart rate (HR, 104.1 ± 11.41 bpm vs. 105.7 ± 9.68 bpm, p = 0.696) and the highest respiratory quotient (RQ, 1.0 ± 0.06 vs. 0.9 ± 0.09, p = 0.643) were not significantly different. The intensity of Tai Chi was described as the highest oxygen uptake of the participants when they performed the Tai Chi divided by their individual maximal oxygen uptake. Tai Chi intensity during Bafa Wubu of Tai Chi (50% ± 11.7% vs. 64% ± 12.5%) was significantly lower than during 24 form simplified Tai Chi.ConclusionThe newly compiled Bafa Wubu of Tai Chi is characterized by lower energy consumption than 24 form simplified Tai Chi.Trial registrationEthics Committee of Sports Science Experiment, Beijing Sport University- 2018010H. Registered 19 June 2018

Exercise interventions in solid organ transplant candidates: A systematic review.

Exercise training may be recommended to solid organ transplant (SOT) candidates to improve fitness and tolerance before surgery. We aimed to determine the acceptance, safety, and effectiveness of exercise interventions in SOT candidates. Online databases were searched. Studies of any design were included. Outcomes of interest were acceptance, safety, exercise capacity, and health-related quality of life. Twenty-three articles were included. Acceptance ranged from 16% to 100%. In the fifteen studies that assessed adverse events, none mentioned any adverse events occurring during the study. Five out of seven studies reported an increase in maximal exercise capacity post-exercise in the intervention group (range of mean change: 0.45 to 2.9mL/kg). Eight out of fourteen studies reported an increase in 6-minute walking distance in the intervention group after the training period (range of mean change: 40-105m). Two articles showed an improvement in the mental composite scores as well as in the physical composite scores post-exercise in the intervention group. There was a lack of significant findings among most randomized controlled trials. Exercise training is acceptable and safe for selective SOT candidates. The effects of exercise training on exercise capacity and quality of life in SOT candidates are unclear.

Genetic loss of AMPK-glycogen binding destabilises AMPK and disrupts metabolism

ObjectiveGlycogen is a major energy reserve in liver and skeletal muscle. The master metabolic regulator AMP-activated protein kinase (AMPK) associates with glycogen via its regulatory β subunit carbohydrate-binding module (CBM). However, the physiological role of AMPK-glycogen binding in energy homeostasis has not been investigated in vivo. This study aimed to determine the physiological consequences of disrupting AMPK-glycogen interactions. MethodsGlycogen binding was disrupted in mice via whole-body knock-in (KI) mutation of either the AMPK β1 (W100A) or β2 (W98A) isoform CBM. Systematic whole-body, tissue and molecular phenotyping was performed in KI and respective wild-type (WT) mice. ResultsWhile β1 W100A KI did not affect whole-body metabolism or exercise capacity, β2 W98A KI mice displayed increased adiposity and impairments in whole-body glucose handling and maximal exercise capacity relative to WT. These KI mutations resulted in reduced total AMPK protein and kinase activity in liver and skeletal muscle of β1 W100A and β2 W98A, respectively, versus WT mice. β1 W100A mice also displayed loss of fasting-induced liver AMPK total and α-specific kinase activation relative to WT. Destabilisation of AMPK was associated with increased fat deposition in β1 W100A liver and β2 W98A skeletal muscle versus WT. ConclusionsThese results demonstrate that glycogen binding plays critical roles in stabilising AMPK and maintaining cellular, tissue and whole-body energy homeostasis.

63Effects of exercise-based cardiac rehabilitation and detraining on exercise capacity and cardiac function in patients with atrial fibrillation: a randomized controlled trial with 1-year follow-up

Abstract Introduction We aimed to determine whether maximal exercise capacity, left ventricular function, and quality of life (QoL) scores are sustained in patients with atrial fibrillation (AF) after termination of training following exercise-based cardiac rehabilitation (ECR). Methods In a prospective study, 58 patients with AF (age, 62 ± 7 years) were randomized into an exercise training group for 12 months (ECR, n = 13), a group with 6-month detraining after a 6-month exercise training (DT, n = 15), and a medical treatment only group (MT, n = 30). For exercise training, cycling on a bicycle ergometer was performed in the DT and ECR groups 3 times a week for 6 and 12 months, respectively. Each session started with a 10-minute warm-up at 60%–70% of the maximal heart rate (HRpeak), followed by four 4-minute intervals at 80%–90% of the HRpeak, with 3 minutes of active recovery at 60%–70% of the HRpeak between intervals, ending with a 5-minute cool-down period. Peak exercise oxygen consumption (Vo2), left ventricular function, plasma lipid level, N-terminal pro B-type natriuretic peptide level, and QoL score were measured at baseline, after 6 months of training, and after additional 6 months of continuous training or detraining follow-up assessments. Results Six months of exercise training increased the peak Vo2 (ECR: 28.2 ± 7.0 ml/[kg·min] and DT: 28.0 ± 8.3 ml/[kg·min] vs. MT: 23.0 ± 5.2 ml/[kg·min], p= 0.047) and QoL scores (36-Item Short-form Health Survey) and decreased the total cholesterol level (ECR: 146.8 ± 43.8 mg/dl and DT: 140.6 ± 22.4 vs. MT: 182 ± 44.2 mg/dl, p = 0.008). Detraining resulted in an increase in QoL score and a decrease in total cholesterol level (ECR: 142.8 ± 21.4 mg/dl and DT: 151.8 ± 39.8 vs. MT: 176.8 ± 34.2 mg/dl, p = 0.017). However, the exercise training-induced increase in peak Vo2 reverted to the baseline level after detraining (ECR: 27.1 ± 5.1 ml/kg/min vs. DT: 24.4 ± 7.2 ml/[kg·min] and MT: 21.5 ± 4.86 ml/[kg·min], p = 0.017). The resting left ventricular systolic and diastolic functions were not significantly different, with no inter-group difference after 6 months of training and 6 months of continuous training or detraining. Conclusions As the QoL scores are maintained despite peak Vo2 being lowered by detraining after an exercise training period in patients with AF, physicians should encourage patients’ participation in a continuous exercise program to sustain the improvement in both the QoL score and peak Vo2 with exercise training. Further studies with larger sample sizes are needed to observe the long-term effects of exercise training and detraining.

P305 Evaluation of maximum exercise capacity and its relationship to lung volumes and capacities and body composition of children with cystic fibrosis

P305 Evaluation of maximum exercise capacity and its relationship to lung volumes and capacities and body composition of children with cystic fibrosis

Ischemic Preconditioning Enhances Aerobic Adaptations to Sprint-Interval Training in Athletes Without Altering Systemic Hypoxic Signaling and Immune Function.

Optimizing traditional training methods to elicit greater adaptations is paramount for athletes. Ischemic preconditioning (IPC) can improve maximal exercise capacity and up-regulate signaling pathways involved in physiological training adaptations. However, data on the chronic use of IPC are scarce and its impact on high-intensity training is still unknown. We investigated the benefits of adding IPC to sprint-interval training (SIT) on performance and physiological adaptations of endurance athletes. In a randomized controlled trial, athletes included eight SIT sessions in their training routine for 4 weeks, preceded by IPC (3 × 5 min ischemia/5 min reperfusion cycles at 220 mmHg, n = 11) or a placebo (20 mmHg, n = 9). Athletes were tested pre-, mid-, and post-training on a 30 s Wingate test, 5-km time trial (TT), and maximal incremental step test. Arterial O2 saturation, heart rate, rate of perceived exertion, and quadriceps muscle oxygenation changes in total hemoglobin (Δ[THb]), deoxyhemoglobin (Δ[HHb]), and tissue saturation index (ΔTSI) were measured during exercise. Blood samples were taken pre- and post-training to determine blood markers of hypoxic response, lipid-lipoprotein profile, and immune function. Differences within and between groups were analyzed using Cohen's effect size (ES). Compared to PLA, IPC improved time to complete the TT (Mid vs. Post: −1.6%, Cohen's ES ± 90% confidence limits −0.24, −0.40;−0.07) and increased power output (Mid vs. Post: 4.0%, ES 0.20, 0.06;0.35), Δ[THb] (Mid vs. Post: 73.6%, ES 0.70, −0.15;1.54, Pre vs. Post: 68.5%, ES 0.69, −0.05;1.43), Δ[HHb] (Pre vs. Post: 12.7%, ES 0.24, −0.11;0.59) and heart rate (Pre vs. Post: 1.4%, ES 0.21, −0.13;0.55, Mid vs. Post: 1.6%, ES 0.25, −0.09;0.60). IPC also attenuated the fatigue index in the Wingate test (Mid vs. Post: −8.4%, ES −0.37, −0.79;0.05). VO2peak and maximal aerobic power remained unchanged in both groups. Changes in blood markers of the hypoxic response, vasodilation, and angiogenesis remained within the normal clinical range in both groups. We concluded that IPC combined with SIT induces greater adaptations in cycling endurance performance that may be related to muscle perfusion and metabolic changes. The absence of elevated markers of immune function suggests that chronic IPC is devoid of deleterious effects in athletes, and is thus a safe and potent ergogenic tool.

Exercise Capacity and Activities of Daily Living are Related in Patients With Chronic Obstructive Pulmonary Disease

IntroductionThe knowledge of the relationship between exercise capacity and activities of daily living (ADLs) is important to minimize the negative outcomes in ADLs resulting from reduced exercise capacity in patients with chronic obstructive pulmonary disease (COPD). There is a limited study about the association between exercise capacity and ADLs in patients with COPD. This study aimed to investigate the relationship between maximal exercise capacity and ADLs in patients with GOLD stage II–III COPD. MethodsTwenty-seven clinically stable GOLD stage II–III COPD patients were included (mean age=58.59±9.63 years and mean FEV1=50.6±13.7%) in this cross-sectional study. Maximal and submaximal exercise capacity were evaluated using an incremental shuttle walk test (ISWT) and 6-min walk test (6MWT), respectively. Activities of daily living were assessed using Glittre-ADL test. ResultsThe ISWT distance was significantly correlated with Glittre-ADL test time (r=−0.517, p=0.006). There was also a negative correlation between 6MWT distance and Glittre-ADL test time (r=−0.506, p=0.007). ConclusionA moderate relationship was found between maximal exercise capacity and general activities of daily living performance. The reduction in exercise capacity increases the negative influences in ADLs and strengthens our beliefs that exercise interventions in pulmonary rehabilitation could influence activities of daily living positively.

Muscle oxygenation during hypoxic exercise in humans: Effect of high‐affinity hemoglobin

BackgroundIn humans, maximal exercise capacity is reduced during hypoxic environmental conditions. In response to hypoxia, the hemoglobin binding affinity is decreased, promoting oxygen off‐loading at the tissue level and causing a right‐shift of the oxyhemoglobin dissociation curve (ODC). However, comparative biology demonstrates many species (e.g. Bar‐headed geese), who are adapted to hypoxia instead have high‐affinity hemoglobin (left‐shifted ODC). Therefore we studied unique human participants with hemoglobinopathies that result in high affinity hemoglobin (HAH) to investigate the role of oxygen affinity in exercise performance and tissue oxygenation during hypoxic conditions.MethodsHAH participants (n=5, 1M/4F, Age= 34±11 yr, P50=16±1 mmHg) and matched control participants (n=12, 5M/7F, age=39±12 yr, and P50=26±1 mmHg) completed two incremental exercise tests to exhaustion on a cycle ergometer under two conditions: 1) room air (FiO2= 0.21, NORM), and 2) normobaric hypoxia gas mixture (FiO2= 0.15, HYP), separated by a 45 minute break. The vastus lateralis (VL) muscle was studied using frequency‐domain near infrared spectroscopy (NIRS) to measure concentrations of oxygenated ([OxyHb+Mb]), deoxygenated ([DeoxyHb+Mb]) hemoglobin and myoglobin, and tissue saturation (StO2). Data were analyzed using a three‐way (Inspirate [HYP, NORM], Hb type [Normal, HAH], exercise intensity [Rest, 40, 60, 80, 100% normoxic PPO]) univariate analysis of variance.ResultsHAH had an attenuated decline in exercise tolerance (peak power output at maximal exertion) in HYP compared to controls (HAH: 2.9±6.4% decline vs CTL: 11.7±5.4% decline, P&lt;0.05). There was a significant effect of Hb type on [DeoxyHb+Mb] (P=0.048) suggesting less O2 offloading in HAH compared to controls in the VL at rest and throughout graded exercise in both NORM and HYP. There were no significant effects of inspirate or exercise intensity on [DeoxyHb+Mb], and no significant differences in [OxyHb+Mb] between HAH and controls. There was a significant effect of Hb type on StO2 in NORM controls (P&lt;0.01) However, during hypoxic exercise StO2 was the same in both HAH and controls except at end exercise (HAH 64.1±6.4% vs CTL: 62.1±4.2%, P&lt;0.05).ConclusionHAH individuals have less oxygen off‐loading at rest and during exercise but higher tissue saturation during exercise in NORM compared to controls. Our results suggest that the similar levels of exercise capacity in hypoxia for HAH are due, at least in part, to maintenance of microvascular extraction similar to that during normoxic exercise. Future studies utilizing direct measurements of skeletal muscle blood flow during exercise are needed to understand integrative exercise in HAH patients.Support or Funding InformationThis work was funded by NIH R‐35‐HL139854 and the Mayo Foundation.Muscle oxygenation during graded exercise tests in normoxia and hypoxia. Data are presented as means ± standard error. Abbreviations: [OxyHb+Mb], concentration of oxygenated hemoglobin+myoglobin; [DeoxyHb+MB], concentration of deoxygenated hemoglobin+ myoglobin; PPO, peak power output. † denotes significant main effect of Hb types across all workloads. * denotes significant difference from CTL at same %PPO.Figure 1

Endothelial shear stress in the common carotid artery during boxing training in prehypertension

PURPOSEEndothelial function is highly regulated by the friction between blood flow and the endothelium. Endothelial shear stress (ESS) is defined as the dragging force generated by this interaction and it has been reported that low ESS affects nitric oxide bioavailability which in turn might increase blood pressure. Exercise programs are one of the best suited approaches to treat high blood pressure, however, there are no studies describing changes on ESS in the common carotid artery during upper‐body exercise, such as boxing training. Therefore, the purpose of this study was to quantify ESS in the common carotid artery during 60% and 95% of the maximal boxing exercise capacity in normotensive and pre‐hypertensive subjects.METHODSA total of 5 healthy normotensive and 5 pre‐hypertensive subjects matched by age, gender, height, and weight were recruited for this study. All 10 subjects performed two boxing exercise tests. The first was a graded maximal boxing test to estimate their maximal oxygen uptake (VO2max). The second one, performed 48 hours after the first evaluation, was a 2‐workload steady‐state boxing test at 60%VO2max and at 95%VO2max for 3 minutes each. A high‐definition Doppler ultrasound recorded common carotid artery diameters and blood flow velocities throughout each steady‐state condition. ESS was estimated using Womersley’s approximation.RESULTSThere was a significant increase in antegrade ESS with higher workloads in both groups (p &lt; 0.05 for all). No difference were found in anterograde ESS at baseline (Normotensive: 33.9±13.9 dynes/cm2, Pre‐HTA: 34.7±5.5 dynes/cm2; p = 0.936), at 60%VO2max (Normotensive: 51.3±19.1 dynes/cm2, Pre‐HTA: 49.6±7.6 dynes/cm2; p = 0.894, and at 95%VO2max (Normotensive: 72.9±30.9 dynes/cm2, Pre‐HTA: 85.2±12.5 dynes/cm2; p = 0.560) between both groups. Meanwhile, no retrograde blood flow was present at baseline for either groups, but it was identified at 60%VO2max (Normotensive: 8.1±0.7 dynes/cm2, Pre‐HTA: 7.8±7.8 dynes/cm2; p = 0.971) and 95%VO2max (Normotensive: 22.5±18.9 dynes/cm2, Pre‐HTA: 20.8±5.6 dynes/cm2; p = 0.891).CONCLUSIONESS increases in an exercise‐intensity manner during boxing training in normotensive and prehypertensive population. Boxing training might be beneficial in high blood pressure prevention due to increments on ESS.

Right Ventricular Function Coupling to the Pulmonary Circulation Predicts Exercise Tolerance in Patients with Heart Failure and Reduced Ejection Fraction. Insight from the Evaluation of Resynchronization Therapy for Heart Failure (EARTH) Trial

Exercise tolerance has important prognostic value in patients with heart failure and reduced ejection fraction (HFrEF). The relationship between right ventricular function and its coupling to pulmonary circulation (RV-PA) and cardiopulmonary exercise tests (CPET) is not fully understood. We aimed to evaluate the value of RV echocardiographic parameters, including RV-PA, to predict exercise tolerance in HFrEF patients. We performed a sub-analysis of EARTH, which enrolled HFrEF patients undergoing defibrillator implantation. At baseline, an echocardiogram and various CPET [peak VO2; minute ventilation/carbon dioxide production slope (VE/VCO2); 6-minute walk distance (6MWD) and submaximal exercise duration (SED)] were performed. The primary outcome was the correlation of RV-PA (using TAPSE/sPAP, tricuspid annular plane systolic excursion on pulmonary artery systolic pressure ratio (T/P)) with peak VO2. Secondary outcomes include correlation between various RV parameters such as size [diameter at inlet and end-diastolic area in apical 4-chamber], RV function [TAPSE; right ventricular fractional area change (RV-FAC); RV myocardial performance index (RV-MPI)], sPAP and tricuspid regurgitation grade (TRG); and CPET variables. Univariate and multivariate linear regression models were used on patients for which both TAPSE and sPAP were available. 205 patients were enrolled in EARTH, with 100 having data on both TAPSE and sPAP (Men: 70.0%; NYHA class II: 55.0%; mean LVEF 26.5±7.8%). T/P was the only parameter found to be predictive of peak VO2 (β=6.8, p<0.01), together with BMI for 6MWD (β=72.4, p=0.04). ROC analysis for T/P value predictive of peak VO2 ≤14mL/kg/min showed sensitivity and specificity of 0.63 and 0.62 respectively, and area under the curve (AUC) of 0.66 (p<0.01) for an optimal threshold ≤0.45. T/P and RV-MPI were both predictors (β=-18.0, p<0.01; β=18.5, p<0.01 respectively) of VE/VCO2 slope, while only TRG and BMI predicted SED (β=-3.2, p=0.03). In HFrEF patients, RV-PA coupling (using TAPSE/sPAP) is a powerful predictor of maximal and submaximal exercise capacity and has a greater predictive value than the usual parameters including age, sex and LVEF.

Pulmonary Rehabilitation in Patients with Pulmonary Sarcoidosis: Impact on Exercise Capacity and Fatigue

Background: There is limited evidence regarding the impact of multidisciplinary pulmonary rehabilitation (PR) on exercise capacity and fatigue in patients with pulmonary sarcoidosis. The aim of this study was to evaluate the impact on exercise capacity and fatigue following PR, and to examine whether baseline fatigue was related to change in peak oxygen uptake (ΔV̇O_2peak). Methods: Forty-one patients with pulmonary sarcoidosis attending a 4-week inpatient PR program were recruited to this pre-post study. Both maximal exercise capacity, defined as V̇O_2peak and measured with a cardiopulmonary exercise test, and fatigue, assessed with the Fatigue Assessment Scale (score 10–50 points), were measured before and after PR. Results: There was a statistically significant improvement in V̇O_2peak (1.2 ± 2.3 mL/kg/min, p = 0.002), and fatigue decreased significantly (–1.7 ± 3.9 points, p = 0.009) following PR. Unadjusted linear regression analyses demonstrated that age (B = –0.076, p = 0.017) and baseline fatigue (B = 0.196, p = 0.001) were predictors for change in V̇O_2peak, while in adjusted analyses (age, sex, baseline V̇O_2peak, baseline fatigue, and diffusion capacity of the lung for carbon monoxide), only baseline fatigue predicted change in V̇O_2peak following PR (B = 0.165, p = 0.026). Conclusion: A 4-week multidisciplinary PR program improves maximal exercise capacity and reduces fatigue in patients with pulmonary sarcoidosis. Baseline fatigue only partly predicted change in V̇O_2peak following PR.

RIGHT VENTRICULAR FUNCTION COUPLING TO THE PULMONARY CIRCULATION PREDICTS EXERCISE TOLERANCE IN PATIENTS WITH HEART FAILURE AND REDUCED EJECTION FRACTION: INSIGHT FROM THE EVALUATION OF RESYNCHRONIZATION THERAPY FOR HEART FAILURE (EARTH) TRIAL

Purpose Exercise tolerance has important prognostic value in patients with heart failure and reduced ejection fraction (HFrEF). The relationship between right ventricular function and its coupling to pulmonary circulation (RV-PA) and cardiopulmonary exercise tests (CPET) is not fully understood. We aimed to evaluate the value of RV echocardiographic parameters, including RV-PA, to predict exercise tolerance in HFrEF patients. Methods We performed a sub-analysis of EARTH, which enrolled HFrEF patients undergoing defibrillator implantation. At baseline, an echocardiogram and various CPET [peak VO2; minute ventilation/carbon dioxide production slope (VE/VCO2); 6-minute walk distance (6MWD) and submaximal exercise duration (SED)] were performed. The primary outcome was the correlation of RV-PA (using TAPSE/sPAP, tricuspid annular plane systolic excursion on pulmonary artery systolic pressure ratio (T/P)) with peak VO2. Secondary outcomes include correlation between various RV parameters such as size [diameter at inlet and end-diastolic area in apical 4-chamber], RV function [TAPSE; right ventricular fractional area change (RV-FAC); RV myocardial performance index (RV-MPI)], sPAP and tricuspid regurgitation grade (TRG); and CPET variables. Univariate and multivariate linear regression models were used on patients for which both TAPSE and sPAP were available. Results 205 patients were enrolled in EARTH, with 100 having data on both TAPSE and sPAP (Men: 70.0%; NYHA class II: 55.0%; mean LVEF 26.5±7.8%). T/P was the only parameter found to be predictive of peak VO2 (β=6.8, p Conclusion In HFrEF patients, RV-PA coupling (using TAPSE/sPAP) is a powerful predictor of maximal and submaximal exercise capacity and has a greater predictive value than the usual parameters including age, sex and LVEF.

Relationship of left atrial expansion index to exercise tolerance, pretest probability of restenosis, and positive predictive value of treadmill test in coronary artery disease.

Whether left atrial (LA) expansion index is associated with coronary restenosis, and exercise capacity (EC) reduction in coronary artery disease has not been established. This study analyzed 342 consecutive patients who had received a coronary stent implant. A treadmill exercise test (TET) was administered in all participants. The LA expansion indices were measured immediately before and after TET. Maximal EC measured on a breath-by-breath basis by a metabolic cart with gas analyzers and recorded as metabolic equivalent task. All patients with positive TET results received angiography, and those with restenosis received complete revascularization by either percutaneous coronary intervention (PCI) or bypass surgery. The LA expansion index and EC before and 1month after PCI were then compared. Out of 342 patients, 74 had positive TET results, and 54 had restenosis in angiography. Low LA expansion index was associated with poor EC. In patients with LA expansion index>200%, only 5% had restenosis with 38.5% positive predictive value (PPV) of TET. In patients with LA expansion index<100%, however, 64.3% had restenosis with 94.7% PPV of TET. Restenosis induced low pre-TET LA expansion index and further decline during TET. The LA expansion index significantly (P .001) improved from 133±64% before PCI to184±86% after PCI, and the improvement corresponded with EC recovery. A 10% reduction in LA expansion index was associated with a 15% increase in pretest probability of restenosis. The LA expansion index is associated with EC, pretest probability of restenosis, and PPV of TET. Revascularization improves both EC and LA expansion index.

Influence of high affinity haemoglobin on the response to normoxic and hypoxic exercise.

Theoretical models suggest there is no benefit of high affinity haemoglobin to preserve maximal oxygen uptake in acute hypoxia but the comparative biology literature has many examples of species that are evolutionarily adapted to hypoxia and have high affinity haemoglobin. We studied humans with high affinity haemoglobin and compensatory polycythaemia. These subjects performed maximal exercise tests in normoxia and hypoxia to determine how their altered haemoglobin affinity impacts hypoxic exercise tolerance. The high affinity haemoglobin participants demonstrated an attenuated decline in maximal aerobic capacity in acute hypoxia. Those with high affinity haemoglobin had no worsening of pulmonary gas exchange during hypoxic exercise but had greater lactate and lower pH than controls for all exercise bouts. High affinity haemoglobin and compensatory polycythaemia mitigated the decline in exercise performance in acute hypoxia through a higher arterial oxygen content and an unchanged pulmonary gas exchange. The longstanding dogma is that humans exhibit an acute reduction in haemoglobin (Hb) binding affinity for oxygen that facilitates adaptation to moderate hypoxia. However, many animals have adapted to high altitude through enhanced Hb binding affinity for oxygen. The objective of the study was to determine whether high affinity haemoglobin (HAH) affects maximal and submaximal exercise capacity. To accomplish this, we recruited individuals (n=11, n=8 females) with HAH (P50 =16±1mmHg), had them perform normoxic and acute hypoxic (15% inspired oxygen) maximal exercise tests, and then compared their results to matched controls (P50 =26±1, n=14, n=8 females). Cardiorespiratory and arterial blood gases were collected throughout both exercise tests. Despite no difference in end-exercise arterial oxygen tension in hypoxia (59±6 vs. 59±9mmHg for controls and HAH, respectively), the HAH subjects' oxyhaemoglobin saturation ( ) was ∼7% higher. Those with HAH had an attenuated decline in maximal oxygen uptake ( ) (4±5% vs. 12±%, p<0.001) in hypoxia and the change in between trials was related to the change in (r=-0.75, p<0.0001). Compared to normoxia, the controls' alveolar-to-arterial oxygen gradient significantly increased during hypoxic exercise, whereas pulmonary gas exchange in HAH subjects was unchanged between the two exercise trials. However, arterial lactate was significantly higher and arterial pH significantly lower in the HAH subjects for both exercise trials. We conclude that HAH attenuates the decline in maximal aerobic capacity and preserves pulmonary gas exchange during acute hypoxic exercise. Our data support the comparative biology literature indicating that HAH is a positive adaptation to acute hypoxia.

Smartphone Cardiac Rehabilitation, Assisted Self-Management Versus Usual Care: Protocol for a Multicenter Randomized Controlled Trial to Compare Effects and Costs Among People With Coronary Heart Disease.

BackgroundAlternative evidence-based cardiac rehabilitation (CR) delivery models that overcome significant barriers to access and delivery are needed to address persistent low utilization. Models utilizing contemporary digital technologies could significantly improve reach and fidelity as complementary alternatives to traditional center-based programs.ObjectiveThe aim of this study is to compare the effects and costs of the innovative Smartphone Cardiac Rehabilitation, Assisted self-Management (SCRAM) intervention with usual care CR.MethodsIn this investigator-, assessor-, and statistician-blinded parallel 2-arm randomized controlled trial, 220 adults (18+ years) with coronary heart disease are being recruited from 3 hospitals in metropolitan and regional Victoria, Australia. Participants are randomized (1:1) to receive advice to engage with usual care CR or the SCRAM intervention. SCRAM is a 24-week dual-phase intervention that includes 12 weeks of real-time remote exercise supervision and coaching from exercise physiologists, which is followed by 12 weeks of data-driven nonreal-time remote coaching via telephone. Both intervention phases include evidence- and theory-based multifactorial behavior change support delivered via smartphone push notifications. Outcomes assessed at baseline, 12 weeks, and 24 weeks include maximal aerobic exercise capacity (primary outcome at 24 weeks), modifiable cardiovascular risk factors, exercise adherence, secondary prevention self-management behaviors, health-related quality of life, and adverse events. Economic and process evaluations will determine cost-effectiveness and participant perceptions of the treatment arms, respectively.ResultsThe trial was funded in November 2017 and received ethical approval in June 2018. Recruitment began in November 2018. As of September 2019, 54 participants have been randomized into the trial.ConclusionsThe innovative multiphase SCRAM intervention delivers real-time remote exercise supervision and evidence-based self-management behavioral support to participants, regardless of their geographic proximity to traditional center-based CR facilities. Our trial will provide unique and valuable information about effects of SCRAM on outcomes associated with cardiac and all-cause mortality, as well as acceptability and cost-effectiveness. These findings will be important to inform health care providers about the potential for innovative program delivery models, such as SCRAM, to be implemented at scale, as a complement to existing CR programs. The inclusion of a cohort comprising metropolitan-, regional-, and rural-dwelling participants will help to understand the role of this delivery model across health care contexts with diverse needs.Trial RegistrationAustralian New Zealand Clinical Trials Registry (ACTRN): 12618001458224; anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374508.International Registered Report Identifier (IRRID)DERR1-10.2196/15022

Efficacy of extended, comprehensive outpatient cardiac rehabilitation on cardiovascular risk factors: A nationwide registry

Cardiac rehabilitation (CR) is a key component of the treatment of cardiac diseases. The Austrian outpatient CR model is unique, as it provides patients with an extended professionally supervised, multidisciplinary program of 4-6 weeks of phase II (OUT-II) and 6-12 months of phase III (OUT-III) CR. The aim of this analysis was to assess the efficacy of the Austrian outpatient CR model using a nationwide registry. Data of all consecutive patients (N = 7560) who completed OUT-II and/or OUT-III between 1 January 2005 and 31 December 2015 were entered prospectively into a registry. OUT-III patients were analyzed separately according to whether the preceding phase II was performed as outpatient (OUT-II/OUT-III, N = 2403) or in-patient (IN-II/OUT-III, N = 2789). All patients underwent assessment of anthropometry, resting blood pressure, lipid profile, fasting blood glucose, exercise capacity, quality of life, anxiety and depression. During OUT-II, patients significantly improved their metabolic risk factor profile and increased exercise capacity by 14.3%. OUT-II/OUT-III patients achieved an additional increase in exercise capacity by 10%, further improvement in high-density lipoprotein (HDL) and stabilization of the remaining risk factors. IN-II/OUT-III patients increased their maximal exercise capacity by 18.4% and there was improvement in blood pressure, HDL, low-density lipoprotein and glucose levels. Extended, professionally supervised, multidisciplinary outpatient CR in a large nationwide registry of consecutive patients consistently improved maximal exercise capacity and relevant modifiable cardiovascular risk factors beyond effects seen after IN- or OUT-II alone.

Adaptation to reduced lung function in children and young people with spinal deformity

BackgroundSevere scoliosis can affect respiratory function in growing patients and produce cardiopulmonary complications, leading to significant morbidity. The development of spinal deformity may impact on young patients’ level of function and reported quality of life (QOL). The aim of this study was to investigate the relationship between lung function, exercise capacity and quality of life in young patients with spinal deformity. MethodsThis is a retrospective analysis of 104 patients (31% male, 69% female with mean age 14.9yrs). 77% of patients had an adolescent idiopathic scoliosis, with the remainder having other scoliosis diagnoses or Scheuermann’s kyphosis. Principal outcomes included Spirometry [FEV1, FVC], Whole Body Plethysmography, Cardiopulmonary Exercise Testing [CPET] and patient outcome questionnaires (with SRS-22). CPET measures included maximal exercise capacity [VO2peak] as well as VO2 at ventilatory threshold [VT] expressed as %predicted VO2max-a measure of physical conditioning, and minute ventilation [VE] from which breathing reserve [BR] could be calculated. ResultsMean (±SD) main thoracic scoliosis was 59.9⁰ (±15.2⁰), and mean kyphosis in those with Scheuermann’s condition was 95.3⁰ (±11.5⁰). No correlation was elicited between FEV1 or FVC (%predicted) and VO2peak (%predicted) in this patient cohort. Greater thoracic curves were associated with lower FEV1 (%predicted), r = −0.343, p = 0.001, FVC (%predicted), r = −0.307, p = 0.003 and BR (%) at the end of exercise (r = −0.-0.459, p < 0.001). The patient cohort had a mean (sd) VO2peak of 98(17) %predicted, with greater VO2peak levels recorded in female subjects, those of younger age and those with higher scoliosis angles. Those with better lung function [FEV1 (%predicted)] had better BR (%) at the end of exercise (r = 0.483, p < 0.001). SRS-22 scores correlated significantly with VO2peak (%predicted) (total SRS-22 versus VO2peak (%predicted), r = 0.336, p = 0.002). ConclusionLarger thoracic scoliotic curves are associated with poorer lung function but better exercise capacity, likely related to higher levels of physical conditioning. Higher QOL scores were recorded in patients who had greater VO2peak levels, suggesting that exercise capacity may be a protective factor for emotional well-being in patients with spinal deformity.

Aerobic exercise has an anxiolytic effect on streptozotocin-induced diabetic rats

Diabetes is a metabolic disorder characterized by hyperglycemia and impaired insulin secretion or action. Psychological comorbidities, such as depression and anxiety, are more common in people with diabetes. Exercise results in anxiolytic effects, as demonstrated in numerous studies. This study aims to evaluate potential anxiolytic effects of aerobic exercise in streptozotocin (STZ)‑induced diabetes. Male Wistar albino rats (n=40) were randomly divided into four groups of control, exercise, diabetes, and diabetes + exercise. Diabetes was induced with a single i.p. injection of STZ. The incremental load test was applied to exercise groups to determine maximal exercise capacity. Rats exercised on a treadmill at 70% of their maximal capacity for 45 min, five days per week for 12 weeks. On the day after the last exercise session the open field test and elevated plus maze test were carried out. Diabetes caused an increase in anxiety level, reflected in stretch‑attend posture, self‑grooming behaviors, and freezing time, with no significant changes for other behavioral parameters. Training normalized diabetes‑induced deteriorations and also induced a significant anxiolytic effect both on diabetic and non‑diabetic rats. This effect was observed for all behavioral parameters. The results of the open field test and elevated plus maze were consistent. The current results demonstrated a slight increase in anxiety with diabetes and a prominent anxiolytic effect of aerobic exercise. Considering the conflicting results in exercise‑anxiety studies, this study hig hlights the importance of individually designed exercise protocols.