Mean Peak VO2 Research Articles

P1557Sustainable effectiveness of cardiac rehabilitation in elderly patients in 7 European countries: main results from the EU-CARE study

Abstract Background The EU-CaRE project aims to obtain the evidence base to improve, tailor and optimise cardiac rehabilitation (CR) programmes regarding sustainable effectiveness, cost-effectiveness and participation level in the elderly. Purpose To compare the effect of CR programmes in 7 European countries on the main outcome. Methods The observational EU-CaRE study is a prospective study with eight participating CR sites in seven countries (Denmark, France, Germany, Italy, the Netherlands, Spain and Switzerland). Consecutive patients age 65 or older with coronary heart disease or valve surgery undergoing CR were included. Data were obtained at baseline (T0), at the end of CR (T1) and at 1 year (T2). VO2peak was assessed by cardiopulmonary exercise test. We compared changes in VO2peak across sites in multilevel regression models for repeated measures, adjusting for age, gender, baseline VO2peak, comorbidities, CVD risk factors and educational attainment. Results are reported separately for patients undergoing surgery (CABG/valve replacement) and other indications (MI/stable CAD/PCI). Results 1633 patients were included, and VO2peak was available at all three timepoints for 1243 patients (76%), 492 undergoing surgery and 751 for other indications. Lag time from index event to first CPET and baseline VO2peak varied significantly across centres. Mean age was 72.9 (range 65–90), mean VO2peak at T0 was 16.49 (SD 4.94), at T1, 18.55 (5.33) and at T2 19.03 (5.43) ml/kg/min. For patients not undergoing surgery mean improvement T0-T1 was 1.57 (2.98) and T0-T2 was 1.40 (3.17) ml/kg/min (both p<0.001). In the surgery patients as expected baseline VO2peak was lower but in contrast to non-surgery continued to improve after CR: T0-T1 improvement was 2.77 (2.76) and T0-T2 improvement was 4.29 (3.83) (both p<0.001). At one-year follow-up surgery and non-surgery patients had similar VO2peak (p=0.59). The greatest mean improvement in a site from baseline to one year was 2.04 (3.74) and the smallest 0.59 (2.54) ml/kg/min for non-surgery and, correspondingly 6.13 (4.83) and 1.29 (2.06) ml/kg/min for surgery patients (both multivariable adjusted p for differences between sites p<0.001). In addition to age and gender, baseline and one-year VO2peak was lower in patients with diabetes, hypertension, smokers, patients with other co-morbidity, lower educational attainment and lower mental component score of the SF36. These factors had no systematic impact on the effect of CR. VO2peak at baseline, after CR and 1 year Conclusions The study provides high-quality data on the effectiveness of current CR programmes in Western Europe. Overall, CR was effective in achieving significant improvements in exercise and maintaining these effects. There were significant differences in effect between sites indicating a potential for improvement by adapting CR programs. Acknowledgement/Funding Horizon 2020

Acute Physiological And Perceptual Responses To Body-weight Circuit And Treadmill-based High-intensity Interval Exercise In Children

Research examining acute responses to non-laboratory-based high-intensity interval exercise (HIIE), such as body-weight exercise, in children is lacking. PURPOSE: To compare the acute physiological and perceptual responses between body-weight circuit (CIRC) and treadmill high-intensity interval running (TM) in children. METHODS: Physically active boys (n=17; age = 9.7 ± 1.3 years) completed a graded exercise test to determine maximal heart rate (HRmax), peak oxygen uptake (VO2peak) and maximal aerobic speed (MAS). Time-matched (8-min) CIRC and TM were completed in a randomized order on separate days within a 1 to 2-week period. CIRC consisted of two sets of 4 bouts of 30 s of maximal repetitions of mountain climbers, jump squats, jumping jacks, and burpees, whereas TM included 30 s bouts at 100% MAS. Both had a 30 s recovery between bouts. HR and gas exchange data were continuously assessed using a portable metabolic analyzer and HR monitor, and blood lactate concentration (BLa) was measured pre- and post-exercise. Global affect (PANAS) and exercise enjoyment (PACES) were assessed at baseline and post-exercise. Rating of perceived exertion (RPE), affect (Feeling Scale) and enjoyment (Exercise Enjoyment Scale) were recorded pre- and post-exercise and at 38% and 75% of session completion. RESULTS: Mean peak HR and VO2 were 87% HRmax and 74% VO2peak for CIRC and 89% HRmax and 80% VO2peak for TM, with a significant difference in peak VO2 between regimens (p<0.05). Yet, there were no differences in session HR, VO2 or VE (p>0.05). Post-exercise BLa was significantly higher following CIRC vs. TM (mean difference = 3.0 ± 2.2 mM, p<0.05). RPE, affect and enjoyment responses did not differ between regimens during exercise, and affect did not differ from pre- to post-exercise within or between regimens (p>0.05). Post-exercise enjoyment was significantly lower after CIRC vs. pre-exercise (mean difference = 3.9 ± 1.1, p<0.05). CONCLUSION: Although HR was similar, there was a higher peak VO2 in response to TM, paralleling previous work in adults. The greater BLa accumulation in CIRC may be explained by greater muscle recruitment required for multi-joint, dynamic movements and could explain the reduced post-exercise enjoyment. Future research should investigate higher volume protocols utilizing different body-weight exercises.

Feasibility Of Exercise Prehabilitation During Neo-adjuvant Chemotherapy In Oesophago-gastric Cancer Surgery

PURPOSE: To determine the feasibility and potential benefits of patients diagnosed with operable gastro-oesophageal cancer undertaking a structured-exercise cancer prehabilitation program (prehab) during neo-adjuvant chemotherapy (NAC) versus patients on a standard care pathway. METHODS: Patients were enrolled in a prospective, cohort-controlled trial. Prehab was based on World Health Organisation (WHO) ‘recommended levels of physical activity for adults over the age of 18’. Cardiopulmonary exercise tests (CPEX) were performed at 4 time-points: 1. Baseline/pre-NAC. 2. Post-NAC. 3. Before surgery. 4. After surgery. Participants wore wearable tracker devices. CPEX variables analysed included anaerobic threshold (AT) and peak oxygen uptake (VO2peak). Clinical and pathological data variables were recorded. RESULTS: At time of writing, 25 male and female patients, aged 25 - 78years, had participated in the study; 22 had undergone surgery. Mean baseline AT in the prehab group was 17.57+-3.35SD (range10.77- 20.94; n=10) ml/kg/minute, compared to 15.19+-3.57SD (range 11.10 -22.90; n=12) ml/kg/minute in the control group. Mean baseline V02peak achieved was 27.55+-5.63SD (range 15.18 - 36.83) ml/kg/minute and 23.39+-4.06SD (range 18.75- 29.94)ml/kg/minute, respectively. Mean values of AT and VO2peak between the groups pre-surgery were of little scientific value. However, ΔVO2peak in individual patients showed a trend towards improvement in the prehab cohort.Post-surgery values decreased markedly in both groups: Mean AT prehab decreased to 13.46+-2.29SD (range 10.54-15.91)ml/kg/minute versus 13.10+-2.60SD (range 10-18.4)ml/kg/minute in control group. Mean VO2peak reduced to 20.33+-4.94 (range 14.01-26.81)ml/kg/minute compared to 19.56+-2.74SD (range18.00-24.76)ml/kg/minute respectively. CONCLUSIONS: Cancer prehabilitation during NAC is feasible. Recovery of peak oxygen uptake shows an improvement trend in patients undergoing prehab during and after NAC. Post-surgery mean AT and VO2 values confirm physiological stress in patients undergoing high-risk, intra-thoracic and intra-abdominal oesophagectomy.

The Effect of Sodium Supplementation on Postexercise Hypotension Following Acute Submaximal Aerobic Exercise

PURPOSE: Acute submaximal aerobic exercise confers cardiovascular benefits including a prolonged reduction in blood pressure (BP) termed postexercise hypotension (PEH). PEH is thought to contribute to the chronic BP-lowering effects of aerobic training. Chronic sodium (Na+) supplementation expands plasma volume (PV) and may attenuate PEH. Therefore, this study tested the hypothesis that Na+ supplementation attenuates PEH following acute aerobic exercise. METHODS: Healthy young adults (n=11, age 26 ± 4 years; body mass index 23.5 ± 2.4 kg/m2) consumed a recommended Na+ diet (2,300 mg Na+/d) for 10 days on two occasions; participants also consumed pills containing a total of either 4,000 mg Na+ or a placebo in random order. Participants collected their urine for the final 24 hours of each intervention for quantification of urinary Na+ excretion. On day 10 of each intervention, participants completed 50 minutes of dynamic cycling exercise at 60% VO2peak. Brachial BP was recorded via automated oscillometry before and every 10 minutes after exercise for one hour. The change in PV was estimated using hemoglobin and hematocrit following each intervention. BP responses following exercise were compared using a two-way repeated measures ANOVA. Urinary and blood measures and the nadir in BP after exercise were compared using paired t-tests. RESULTS: The mean VO2peak of participants was 41.6 ± 8.8 ml/min/kg and mean power at 60% VO2peak was 127 ± 40 W. Urinary Na+ excretion was increased following Na+ supplementation (277 ± 50 vs. 153 ± 73 mmol/24 hours, p<0.001). Na+ supplementation expanded PV approximately 10.2 ± 8.9%. Despite significantly greater Na+ excretion, serum [Na+] (141.0 ± 1.8 vs. 141.7 ± 3.0 mEq/L, p=0.34) and plasma osmolality (294 ± 4 vs. 295 ± 6 mOsm/kg H2O, p=0.22) were not different following Na+ supplementation compared to placebo. PEH was observed following both conditions (nadir systolic BP: -4.7 ± 3.8 vs. -4.6 ± 2.9 mmHg, p=0.91 and mean BP: -6.1 ± 4.3 vs. -5.0 ± 3.4 mmHg, p=0.38). However, when comparing Na+ supplementation to placebo, there was not a significant diet effect regarding reductions in systolic BP (p=0.93) or mean BP (p=0.41) following exercise. CONCLUSIONS: These preliminary data suggest that Na+ supplementation does not attenuate PEH following acute aerobic exercise despite increased PV.

Relationship Between Performance Competence and Cardiorespiratory Fitness in Contemporary Dance.

While a foundation of basic cardiorespiratory fitness is beneficial for coping with the physiological demands of dance training and performance, the extent to which cardiorespiratory fitness levels are related to performance ability is not all-together clear. This study aimed to directly compare aerobic capacity (VO2peak) and anaerobic threshold (AT) to an aesthetic competence measure (ACM) in student contemporary dancers. Participants were 18 contemporary dance students and all undertook a one-off treadmill test to volitional exhaustion in the week leading up to a performance to determine VO2peak and AT. In the same week, a final rehearsal for the performance was filmed to allow retrospective analysis of specific performance competence. Mean VO2peak values of 47.67 ± 5.84 ml/kg/min and AT values of 43.18 ± 7.72 ml/kg/min (90.68 ± 11.87 %VO2peak) were recorded, and the mean total ACM score was 52.67 ± 8.74. No significant correlations were found between cardiorespiratory fitness variables and ACM scores. Regression analyses revealed experience level to be the only significant predictor of total ACM score (p<0.05, R2=0.12, SEE=11.91). The range of choreography used for assessment may limit the present study; nevertheless, as level of experience did significantly predict ACM total score, it is suggested that vocational dance training may be developing the performance and technical skills of students but not sufficiently developing their physical conditioning.

Cardiac rehabilitation in the elderly patient in eight rehabilitation units in Western Europe: Baseline data from the EU-CaRE multicentre observational study.

Due to the progressive deconditioning, comorbidities and higher complication rates, elderly patients are in particular need of cardiac rehabilitation. We compared elderly patients (65+ years old) participating in cardiac rehabilitation, focusing on baseline characteristics, risk factor control and functional assessment. The EU-CaRE study is a prospective study comparing cardiac rehabilitation in eight centres across Western Europe. Consecutive patients with acute coronary syndrome, stable coronary artery disease and heart valve replacement undergoing cardiac rehabilitation were included. Of 1633 patients (median age 72 years) participating, 54% had acute coronary syndrome, 33% had stable coronary artery disease and 13% followed valve replacement. Fifty-five per cent had undergone percutaneous coronary intervention and 29% coronary artery bypass grafting. Characteristics varied across centres: 23% (17-27%) were women, 4% (0-12%) were of non-European origin and 16% (4-32%) were living alone. Median time from index event to start of cardiac rehabilitation varied from 11 to 49 days (p < 0.001). Mean VO2peak was relatively low (16 mL/kg per min) and varied significantly between the participating centres, largely unaffected by multivariable adjustment. Overall patients received guideline recommended treatment: 93% (87-97%) were on a statin and 70% (55-85%) an angiotensin-converting enzyme inhibitor/angiotensin receptor blocker. However, risk factor control was inadequate: 58% had three or more risk factors not controlled. EU-CaRE provides a snapshot of the elderly population with heart disease participating in cardiac rehabilitation across countries in Western Europe. Risk factors and exercise capacity indicate the continued need for cardiac rehabilitation in these patients. Of concern, the lag-time to start of cardiac rehabilitation needs improvement in many centres.

The relationships between age and running performance variables in master runners.

Peak aerobic capacity (V̇O2peak) declines with age, but running economy (RE) may not. We evaluated VO2peak and RE in master runners and determined whether age is associated with these measures. In a cross-sectional study, runners completed two running tests within four weeks of a goal race of 10-26.2 miles. Subjects ran for five min at 88% of predicted maximum heart rate, approximating a marathon-intensity effort (MIE), then performed a V̇O2peak test. Running economy in the MIE was measured using oxygen cost with body mass scaled allometrically (alloV̇O2); energy cost (EC), determined using caloric equivalents; and percent of V̇O2peak (%V̇O2peak). Pearson's correlations were used to determine relationships between age and running performance variables. Runners (n = 31, 13 females; mean age 54.9 ± 8.4 years) had a mean VO2peak of 52.5 ± 7.9 ml O2 kg-1 min-1. Age was significantly correlated with V̇O2peak (r = - 0.580, p = 0.001) and alloV̇O2 (r = - 0.454, p = 0.034). Age was related to EC in females (r = 0.649, p = 0.042) and MIE V̇O2 in males (r = - 0.600, p = 0.039). In this population, age was negatively associated with V̇O2peak and alloV̇O2. Females showed a positive relationship between age and EC, while males had a negative correlation between age and MIE V̇O2. Aerobic capacity declines with age, but there may be sex differences in age-related alterations to submaximal running.

Peak Oxygen Uptake in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis: A Meta-Analysis.

To evaluate the magnitude of the difference in VO2peak between patients with Chronic Fatigue Syndrome/ Myalgic Encephalomyelitis (CFS/ME) and apparently healthy controls, 7 databases (Cochrane, PubMed, PsycINFO, Web of Knowledge, Embase, Scopus, Medline) were searched for articles published up to March 2018. Search terms included "chronic fatigue syndrom*"AND ("peak" OR "maxim*" OR "max") AND ("oxygen uptake" OR "oxygen consumption" OR "VO2peak" or "VO2max". Eligibility criteria were adults>18 y with clinically diagnosed CFS/ME, with VO2peak measured in a maximal test and compared against an apparently healthy control group. The methodological quality of included studies was assessed using a modified Systematic Appraisal of Quality for Observational Research critical appraisal framework. A random effects meta-analysis was conducted on 32 cross-sectional studies (effects). Pooled mean VO2peak was 5.2 (95% CI: 3.8-6.6) ml.kg-1min-1 lower in CFS/ME patients vs. healthy controls. Between-study variability (Tau) was 3.4 (1.5-4.5) ml.kg-1min-1 indicating substantial heterogeneity. The 95% prediction interval was -1.9 to 12.2 ml.kg-1min-1. The probability that the effect in a future study would be>the minimum clinically important difference of 1.1 ml.kg-1min-1 (in favour of controls) was 0.88 - likely to be clinically relevant. Synthesis of the available evidence indicates that CFS/ME patients have a substantially reduced VO2peak compared to controls.

Determination of peak cardiorespiratory fitness parameters in children: which averaging method should we use?

ABSTRACTThe purpose of this study was to identify which averaging methods most accurately measures peak cardiorespiratory fitness (CRF) parameters [peak O2 uptake (VO2), peak O2pulse and peak respiratory exchange ratio (RER)] in a sample of healthy children and adolescents. In this cross-sectional multicenter study, we recruited 278 healthy children aged 12–17 years. We compared the mean peak value of three CRF parameters using the recommended averaging methods (30-second block average) with alternative averaging methods such as moving averages or shorter smoothing periods. We also assessed averaging methods for accuracy by individually reviewing breath-by-breath scatter plots. The 30-second block average method resulted in a lower mean peak VO2 and in an increased proportion of underestimated peak values. Using a 30-second moving average significantly increased mean peak values which increased accuracy. Similar results were found for peak RER and peak O2pulse. In conclusion, the currently recommended averaging method (30-second block average) increased the risk of misinterpretation of peak CRF values in children. Using a moving average approach decreased misinterpretation and increased accuracy.

Exercise-based cardiac rehabilitation improves exercise capacity and health-related quality of life in people with atrial fibrillation: a systematic review and meta-analysis of randomised and non-randomised trials

ObjectiveThe aim of this study was to undertake a contemporary review of the impact of exercise-based cardiac rehabilitation (CR) targeted at patients with atrial fibrillation (AF).MethodsWe conducted searches of PubMED,...

COPD assessment test and FEV1: do they predict oxygen uptake in COPD?

BackgroundChronic obstructive pulmonary disease (COPD) manifests itself in complex ways, with local and systemic effects; because of this, a multifactorial approach is needed for disease evaluation, in order to understand its severity and impact on each individual. Thus, our objective was to study the correlation between easily accessible variables, usually available in clinical practice, and maximum aerobic capacity, and to determine models for peak oxygen uptake (VO2peak) estimation in COPD patients.Subjects and methodsIndividuals with COPD were selected for the study. At the first visit, clinical evaluation was performed. During the second visit, the volunteers were subjected to the cardiopulmonary exercise test. To determine the correlation coefficient of VO2peak with forced expiratory volume in 1 second (FEV1) (% pred.) and the COPD Assessment Test score (CATs), Pearson or Spearman tests were performed. VO2 at the peak of the exercise was estimated from the clinical variables by simple and multiple linear regression analyses.ResultsA total of 249 subjects were selected, 27 of whom were included after screening (gender: 21M/5F; age: 65.0±7.3 years; body mass index: 26.6±5.0 kg/m2; FEV1 (% pred.): 56.4±15.7, CAT: 12.4±7.4). Mean VO2 peak was 12.8±3.0 mL⋅kg−1⋅min−1 and VO2peak (% pred.) was 62.1%±14.9%. VO2peak presented a strong positive correlation with FEV1 (% pred.), r: 0.70, and a moderate negative correlation with the CATs, r: -0.54. In the VO2peak estimation model based on the CAT (estimated VO2peak =15.148− [0.185× CATs]), the index explained 20% of the variance, with estimated error of 2.826 mL⋅kg−1⋅min−1. In the VO2peak estimation model based on FEV1 (estimated VO2peak =6.490+ [0.113× FEV1]), the variable explained 50% of the variance, with an estimated error of 2.231 mL⋅kg−1⋅min−1. In the VO2peak estimation model based on CATs and FEV1 (estimated VO2peak =8.441− [0.0999× CAT] + [0.1000× FEV1]), the variables explained 55% of the variance, with an estimated error of 2.156 mL⋅kg−1⋅min−1.ConclusionCOPD patients’ maximum aerobic capacity has a significant correlation with easily accessible and widely used clinical variables, such as the CATs and FEV1, which can be used to estimate peak VO2.

Heart rate response and functional capacity in patients with chronic heart failure with preserved ejection fraction.

AimsThe mechanisms of exercise intolerance in heart failure with preserved ejection fraction (HFpEF) are not yet elucidated. Chronotropic incompetence has emerged as a potential mechanism. We aimed to evaluate whether heart rate (HR) response to exercise is associated to functional capacity in patients with symptomatic HFpEF.Methods and resultsWe prospectively studied 74 HFpEF patients [35.1% New York Heart Association Class III, 53% female, age (mean ± standard deviation) 72.5 ± 9.1 years, and 59.5% atrial fibrillation]. Functional performance was assessed by peak oxygen consumption (peak VO2). The mean (standard deviation) peak VO2 was 10 ± 2.8 mL/min/kg. The following chronotropic parameters were calculated: Delta‐HR (HR at peak exercise − HR at rest), chronotropic index (CI) = (HR at peak exercise − resting HR)/[(220 − age) − resting HR], and CI according to the equation developed by Keteyian et al. (CIK) (HR at peak exercise − HR at rest)/[119 + (HR at rest/2) − (age/2) − 5 − HR at rest]. In a bivariate setting, peak VO2 was positively and significantly correlated with Delta‐HR (r = 0.35, P = 0.003), CI (r = 0.27, P = 0.022), CIK (r = 0.28, P = 0.018), and borderline with HR at peak exercise (r = 0.22, P = 0.055). In a multivariable linear regression analysis that included clinical, analytical, echocardiographic, and functional capacity covariates, the chronotropic parameters were positively associated with peak VO2. We found a linear relationship between Delta‐HR and peak VO2 (β coefficient of 0.03; 95% confidence interval: 0.004–0.05; P = 0.030); conversely, the association among CIs and peak VO2 was exponentially shaped.ConclusionsIn patients with chronic HFpEF, the HR response to exercise was positively associated to patient's functional capacity.

Fatigability and functional performance among older adults with low-normal ankle-brachial index: Cross-sectional findings from the Baltimore Longitudinal Study of Aging

Background and aimsPeripheral artery disease (PAD) is associated with poor mobility and fatigue, but the relationship between preclinical ankle-brachial index (ABI) and early markers of fatigue and functional decline has not been defined. Methods570 adults, 50 and older, from the Baltimore Longitudinal Study of Aging (N = 570), with normal values of ABI (1–1.39), were classified into ABI tertiles. Perceived fatigability was assessed after a 5-min, treadmill walk (1.5 mph) using the Borg rating of perceived exertion (RPE, range 6–20). Functional evaluation included the Health, Aging and Body Composition Physical Performance Battery (HABC PPB), time to complete a 400-m corridor walk (LDCW), and VO2 peak (ml/kg/min). High RPE and poor walking endurance (PWE) were defined as RPE≥10 and taking >5 min for the LDCW, respectively. Differences between tertiles in fatigability and functional measures were tested adjusting for demographics, behavioral characteristics, self-reported fatigue, and medical history. ResultsMean LDCW time and RPE were greater for participants in the lowest tertile compared to those in the highest; mean VO2 peak and HABC PPB scores were lower, suggesting hierarchical associations between fatigability, functional performance, and ABI (p < 0.05 for all). Odds of PWE were greater for those in the lowest ABI tertile compared to the highest; odds of reporting high RPE were greater for those in the middle tertile. ConclusionsLower ABI is associated with poorer physical function and increased fatigability, suggesting that early changes in ABI may infer greater risk of functional decline, even among those who may not progress to PAD.

Changes in Total Cardiac Output and Oxygen Extraction During Exercise in Patients Supported With an HVAD Left Ventricular Assist Device.

Following implantation of a left ventricular assist device (LVAD), acceptable functional performance is now being achieved; however, peak VO2 and peak work load (watts) remain considerably limited. Maximum physical capacity is essentially dependent on generated cardiac output (CO) and arteriovenous oxygen difference (avDO2 ). We investigated the changes in CO and avDO2 during exercise in LVAD patients with an HVAD pump (HeartWare Inc., Framingham, MA, USA). Approximately 6 weeks after implantation, 20 patients (100% male, 60.8 ± 7.3 years old, BMI 25.7 ± 3.3) underwent a six-minute walk test (6MWT), a cardiopulmonary exercise test (CPET), and noninvasive hemodynamic measurement. The mean six-minute walking distance (6MWD) was 403 m (68% of predicted), and mean peak VO2 was 10.9 mL/kg/min (39% of predicted). Mean total CO improved from 3.8 L at rest to 7.0 L at maximum exercise. The mean avDO2 increased from 7.4 mL/dL (44% of oxygen content) at rest to 13.2 mL/dL (75% of oxygen content) at maximum exercise. There was a significant increase in both total CO (P < 0.01) and avDO2 (P < 0.05) between rest and sub-maximum exercise. As exercise levels increased, however, no further significant changes were achieved. Long-term studies, especially in combination with exercise programs, would be desirable in order to observe the development of these parameters.

Pulsatile Hemodynamics Are Associated With Exercise Capacity in Patients With Exertional Dyspnea and Preserved Left Ventricular Ejection Fraction.

Pulsatile hemodynamics are associated with left ventricular filling pressures and diastolic dysfunction. We investigated their relationship with maximum workload and peak oxygen uptake (peak VO2) in patients with exertional dyspnea and preserved left ventricular ejection fraction (LVEF). Radial waveforms from tonometry were processed with a transfer function, pulse wave analysis and wave separation analysis, yielding central aortic pressures and measures of forward (amplitude of forward wave-Pf) and reflected waves (augmentation index-AIx, augmentation pressure-AP, amplitude of backward wave-Pb) and their ratio (reflection magnitude). Aortic pulse wave velocity (aoPWV) was estimated with a validated formula from single-point waveforms. Ergospirometry for assessment of exercise capacity was performed on a bicycle ergometer, using a ramp protocol. Sixty-six patients were included (43 females; mean age 66 years; 83% hypertensives; mean body mass index 28.3 kg/m2). Mean peak VO2 was 17.0 ml/min/kg, mean achieved maximum workload 104.5 watts (80.9% of a reference population). Maximum workload and peak VO2 showed significant inverse relationships with AIx, AP, Pb, and aoPWV (r = -0.26 to -0.57). In multiple adjusted regression models, brachial and aortic pulse pressure, AP, Pf, Pb, and aoPWV were significant independent predictors of maximum workload, whereas AP, AIx75, Pf, Pb, and aoPWV were independently related to peak VO2. Pulsatile hemodynamics are independently associated with objective measures of exercise capacity in patients with normal LVEF.

Arm Cycling Combined with Passive Leg Cycling Enhances VO2peak in Persons with Spinal Cord Injury Above the Sixth Thoracic Vertebra.

Objective: To test whether passive leg cycling (PLC) during arm cycling ergometry (ACE) affects peak oxygen uptake (VO2peak) differently in individuals with spinal cord injury (SCI) at/above the 6th thoracic vertebra (T6) and below T6. Methods: We conducted a cross-sectional study, analyzed by univariate and multivariate regression models. Between- and within-group differences were examined during (a) ACE only, (b) ACE combined with PLC (ACE-PLC), and (c) ACE combined with functional electrical stimulation cycling (FES hybrid). Fifteen SCI subjects were recruited and grouped according to injury level: at/above T6 (SCI-high, n = 8) or below T6 (SCI-low, n = 7). VO2peak tests during ACE only, ACE-PLC, and FES hybrid were performed in random order on separate days. Results: In the SCI-high group, mean (SD) VO2peak was 19% higher during ACE-PLC than during ACE only [21.0 (3.8) vs 17.7 (5.0) mL·kg-1·min-1; p = .002], while VO2peak during FES hybrid cycling was 16% higher than during ACE-PLC [24.4 (4.1) mL·kg-1·min-1; p = .001]. No significant differences among exercise modalities were found for the SCI-low group. Conclusion: Additional training modalities (eg, PLC) during ACE facilitate exercise in SCI-high individuals, but not to the level of the FES hybrid method. Conversely, additional training modalities may not increase training load in SCI-low individuals.

El consumo máximo de oxígeno predice los ingresos recurrentes por insuficiencia cardiaca con fracción de eyección conservada

Introduction and objectivesHeart failure with preserved ejection fraction (HFpEF) is a highly prevalent syndrome with an elevated risk of morbidity and mortality. To date, there is scarce evidence on the role of peak exercise oxygen uptake (peak VO2) for predicting the morbidity burden in HFpEF. We sought to evaluate the association between peak VO2 and the risk of recurrent hospitalizations in patients with HFpEF. MethodsA total of 74 stable symptomatic patients with HFpEF underwent a cardiopulmonary exercise test between June 2012 and May 2016. A negative binomial regression method was used to determine the association between the percentage of predicted peak VO2 (pp-peak VO2) and recurrent hospitalizations. Risk estimates are reported as incidence rate ratios. ResultsThe mean age was 72.5 ± 9.1 years, 53% were women, and all patients were in New York Heart Association functional class II to III. Mean peak VO2 and median pp-peak VO2 were 10 ± 2.8mL/min/kg and 60% (range, 47-67), respectively. During a median follow-up of 276 days [interquartile range, 153-1231], 84 all-cause hospitalizations in 31 patients (41.9%) were registered. A total of 15 (20.3%) deaths were also recorded. On multivariate analysis, accounting for mortality as a terminal event, pp-peak VO2 was independently and linearly associated with the risk of recurrent admission. Thus, and modeled as continuous, a 10% decrease of pp-peak VO2 increased the risk of recurrent hospitalizations by 32% (IRR, 1.32; 95%CI, 1.03-1.68; P = .028). ConclusionsIn symptomatic elderly patients with HFpEF, pp-peak VO2 predicts all-cause recurrent admission.Full English text available from: www.revespcardiol.org/en

Peak Exercise Oxygen Uptake Predicts Recurrent Admissions in Heart Failure With Preserved Ejection Fraction

Introduction and objectivesHeart failure with preserved ejection fraction (HFpEF) is a highly prevalent syndrome with an elevated risk of morbidity and mortality. To date, there is scarce evidence on the role of peak exercise oxygen uptake (peak VO2) for predicting the morbidity burden in HFpEF. We sought to evaluate the association between peak VO2 and the risk of recurrent hospitalizations in patients with HFpEF. MethodsA total of 74 stable symptomatic patients with HFpEF underwent a cardiopulmonary exercise test between June 2012 and May 2016. A negative binomial regression method was used to determine the association between the percentage of predicted peak VO2 (pp-peak VO2) and recurrent hospitalizations. Risk estimates are reported as incidence rate ratios. ResultsThe mean age was 72.5 ± 9.1 years, 53% were women, and all patients were in New York Heart Association functional class II to III. Mean peak VO2 and median pp-peak VO2 were 10 ± 2.8mL/min/kg and 60% (range, 47-67), respectively. During a median follow-up of 276 days [interquartile range, 153-1231], 84 all-cause hospitalizations in 31 patients (41.9%) were registered. A total of 15 (20.3%) deaths were also recorded. On multivariate analysis, accounting for mortality as a terminal event, pp-peak VO2 was independently and linearly associated with the risk of recurrent admission. Thus, and modeled as continuous, a 10% decrease of pp-peak VO2 increased the risk of recurrent hospitalizations by 32% (IRR, 1.32; 95%CI, 1.03-1.68; P = .028). ConclusionsIn symptomatic elderly patients with HFpEF, pp-peak VO2 predicts all-cause recurrent admission.

Effect Of A Nutraceutical Product On Energy, Fatigue, And Perceived Exertion In Healthy Active Adults

PURPOSE: Evaluate the effectiveness of a commercially available nutraceutical product on levels of exercise-related energy, fatigue, and exertion before and after 4 weeks of supplementation. Primary ingredients within the product include a proprietary blend of blueberry extract, green tea extract, L-carnosine, and Vitamin D3 (NT-020) and rhodiola rosea, a plant that purports to boost energy. METHODS: Twenty-seven participants (12 female, 15male, mean BMI = 23) completed baseline assessment of aerobic fitness (mean VO2 peak = 40 mL x kg-1 x min-1) before being randomized into a placebo or supplement condition for four weeks. All participants were involved in regular physical activity three or more days per week. Assessment of energy, fatigue, and perceived exertion responses during and after moderately intense cycle ergometry exercise was conducted before and after the 4-week ingestion period during which participants were instructed to maintain existing exercise activities. RESULTS: Data were analyzed by way of repeated measures ANOVA and dependent t-tests to determine the presence of significant differences across time and between the supplement and placebo conditions. Participants receiving the supplement reported: greater levels of energy and lower levels of fatigue during the initial moments after completing the exercise trial (p < 0.05), greater levels of energy at the midpoint of the exercise trial (p < 0.05) but not at the end of the exercise session (p > 0.05), and lower perceived exertion at four of the six measurement points during exercise (p < 0.05). No differences were observed from pre to post intervention within the placebo condition (p > 0.05). CONCLUSIONS: Findings indicate that a commercially available supplement marketed to boost energy and reduce fatigue can deliver the purported benefits at least in part. Related findings that supplementation for a 4-week period can allow for equal work at a lower rating of perceived exertion provides further, though limited support that this product may have efficacy.

Is There an Oxygen Pulse Threshold During Treadmill Running?

It has been suggested there are two separate breakpoints in the oxygen pulse (O2 pulse = VO2/heart rate) versus workload relationship during incremental cycle ergometry, corresponding to the first and second turn points in the blood lactate response. It is still unclear if these O2 pulse breakpoints can be detected during treadmill running, and if detected, where these thresholds may be located relative to the gas exchange threshold (GET) and respiratory compensation point (RCP). PURPOSE: This study examined the relationship between O2 pulse and exercise intensity to determine if O2 pulse thresholds could be detected during treadmill running, and, if detected, to compare these O2 pulse thresholds to the GET and RCP. METHODS: Twelve, moderately trained runners (6 men and 6 women; age = 23 ± 3 years; height = 175 ± 8 cm; weight = 71 ± 12 kg) completed an incremental treadmill test to exhaustion for the measurement of gas exchange, ventilation, and heart rate parameters, as well as the determination of VO2 peak. The GET and RCP were determined from the breakpoint in the VCO2 versus VO2 and VE versus VCO2 relationships, respectively. The O2 pulse was plotted against VO2 for each subject and the relationship between these two variables was examined using polynomial regression models (linear and quadratic) at an alpha level of p ≤ 0.05. RESULTS: The mean (± SD) VO2 peak was 3.475 ± 0.959 L·min-1 (48.33 ± 7.30 mL·kg-1·min-1). The GET (2.289 ± 0.617 L·min-1) and RCP (3.029 ± 0.867 L·min-1) occurred at 67 ± 5% and 88 ± 4 % of VO2 peak, respectively. The O2 pulse versus VO2 relationship was best explained by a linear fit (r2 = 0.976 - 1.000) for 9 and a quadratic fit (R2 = 0.985 - 0.996) for 3 of the 12 subjects. Only 1 of the 3 subjects with a quadratic fit for the O2 pulse versus VO2 relationship displayed a response consistent with a plateau in the O2 pulse. CONCLUSIONS: The highly linear relationship between O2 pulse and VO2 for 75% of the subjects indicated that O2 pulse thresholds could not be detected during treadmill running using the O2 pulse versus VO2 relationship. These findings do not support the use of the O2 pulse as a non-invasive measure of fatigue thresholds.