scholarly journals Cardiodynamic variables measured by impedance cardiography during a 6-minute walk test are reliable predictors of peak oxygen consumption in young healthy adults

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0252219
Author(s):  
Fang Liu ◽  
Raymond C. C. Tsang ◽  
Alice Y. M. Jones ◽  
Mingchao Zhou ◽  
Kaiwen Xue ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Impedance Cardiography ◽  
Prediction Equation ◽  
Peak Oxygen Uptake ◽  
Cardiopulmonary Exercise Test ◽  
Peak Oxygen Consumption ◽  
Clinical Environment ◽  
Model Stability ◽  
Cardiac Indices ◽  
Minute Walk

Accurate prediction of aerobic capacity is necessary to guide appropriate exercise prescription. It is common to use 6-minute walk distance (6MWD) to predict peak oxygen uptake (VO2peak) in the clinical environment. The aim of this study was to determine whether prediction of VO2peak can be improved by the inclusion of cardiovascular indices derived by impedance cardiography (ICG) during the 6MWT. A total of 62 healthy university students aged 21±1 years completed in separate days, a cardiopulmonary exercise test (CPET) and two 6MWTs (30 min apart), during which heart rate (HR), stroke volume (SV) and cardiac output (CO) were measured by ICG (PhysioFlow® PF07 EnduroTM). The CPET was conducted with the Ergoselect 200 Ergoline and oxygen consumption measured by a MasterScreenTM CPX breath-by-breath metabolic cart. Multiple regression analyses were conducted to generate VO2peak prediction equations using 6MWD with, or without the cardiovascular indices recorded at the end of the best performed 6MWT as predictor variables. The mean peak HR (bpm), SV (ml) and CO (L/min) recorded during 6MWT were 156±18, 95.6±9, 15±2.8 and during CPET were 176±16, 91.3±8, 16.2±2.7, respectively. Analyses revealed the following VO2peak prediction equation: VO2peak = 100.297+(0.019x6MWD)+(-0.598xHR6MWT)+(-1.236xSV6MWT) + (8.671 x CO6MWT). This equation has a squared multiple correlation (R2) of 0.866, standard error of the estimate (SEE) of 2.28 mL/kg/min and SEE:VO2peak (SEE%) of 7.2%. Cross-validation of equation stability using predicted residual sum of squares (PRESS) statistics showed a R2 (Rp2), SEE (SEEp) and SEEp% of 0.842, 2.38 mL/kg/min and 7.6% respectively. The minimal shrinkage of R2 implied regression model stability. Correlation between measured and predicted VO2peak using this equation was strong (r = 0.931, p<0.001). When 6MWD alone was used as the predictor for VO2peak, the generated equation had a lower R2 (0.549), and a higher SEE (4.08 mL/kg/min) and SEE% (12.9%). This is the first study which included cardiac indices during a 6MWT as variables for VO2peak prediction. Our results suggest that inclusion of cardiac indices measured during the 6MWT more accurately predicts VO2peak than using 6MWD data alone.

scholarly journals Impact of COVID-19 on exercise pathophysiology. A combined cardiopulmonary and echocardiographic exercise study

2021 ◽  
Author(s):  
Claudia Baratto ◽  
Sergio Caravita ◽  
Andrea Faini ◽  
Giovanni Battista Perego ◽  
Michele Senni ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Exercise Capacity ◽  
Vascular Function ◽  
Exercise Physiology ◽  
Cardiopulmonary Exercise Test ◽  
Peak Oxygen Consumption ◽  
Peak Exercise ◽  
Exercise Limitation ◽  
Arterial Blood ◽  
Multisystem Involvement

Background. Survivors from COVID-19 pneumonia can present with persisting multisystem involvement (lung, pulmonary vessels, heart, muscle, red blood cells) that may negatively affect exercise capacity. Methods. We sought to determine the extent and the determinants of exercise limitation in COVID-19 patients at the time of hospital discharge. Results. Eighteen consecutive patients with COVID-19 and 1:1 age-, sex-, and body mass index- matched controls underwent: spirometry, echocardiography, cardiopulmonary exercise test and exercise echocardiography for the study of pulmonary circulation. Arterial blood was sampled at rest and during exercise in COVID-19 patients. COVID-19 patients lie roughly on the same oxygen consumption isophlets than controls both at rest and during submaximal exercise, thanks to supernormal cardiac output (p<0.05). Oxygen consumption at peak exercise was reduced by 30% in COVID-19 (p<0.001), due to a peripheral extraction limit. Additionally, within COVID-19 patients, hemoglobin content was associated with peak oxygen consumption (R2=0.46, p=0.002)Respiratory reserve was not exhausted (median [IRQ], 0.59 [0.15]) in spite of moderate reduction of forced vital capacity (79±40%)Pulmonary artery pressure increase during exercise was not different between patients and controls. Ventilatory equivalents for carbon dioxide were higher in COVID-19 patients than in controls (39.5 [8.5] vs 29.5 [8.8], p<0.001), and such an increase was mainly explained by increased chemosensitivity. Conclusions. When recovering from COVID-19, patients present with reduced exercise capacity and augmented exercise hyperventilation. Peripheral factors, including anemia and reduced oxygen extraction by peripheral muscles were the major determinants of deranged exercise physiology. Pulmonary vascular function seemed unaffected, despite restrictive lung changes.

Peak Oxygen Consumption During Cardiopulmonary Exercise Test Improves Risk Stratification in Candidates to Major Lung Resection

CHEST Journal ◽  
2009 ◽  
Vol 135 (5) ◽  
pp. 1260-1267 ◽  
Author(s):  
Alessandro Brunelli ◽  
Romualdo Belardinelli ◽  
Majed Refai ◽  
Michele Salati ◽  
Laura Socci ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Risk Stratification ◽  
Exercise Test ◽  
Lung Resection ◽  
Cardiopulmonary Exercise Test ◽  
Peak Oxygen Consumption ◽  
Cardiopulmonary Exercise

scholarly journals Impaired Economy of Gait and Decreased Six-Minute Walk Distance in Parkinson's Disease

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Leslie I. Katzel ◽  
Frederick M. Ivey ◽  
John D. Sorkin ◽  
Richard F. Macko ◽  
Barbara Smith ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Oxygen Consumption ◽  
Walking Speed ◽  
Treadmill Walking ◽  
The Self ◽  
Peak Oxygen Consumption ◽  
Walk Distance ◽  
Minute Walk Distance ◽  
Minute Walk

Changes in the biomechanics of gait may alter the energy requirements of walking in Parkinson's Disease (PD). This study investigated economy of gait during submaximal treadmill walking in 79 subjects with mild to moderate PD and the relationship between gait economy and 6-minute walk distance (6 MW). Oxygen consumption (VO2) at the self-selected treadmill walking speed averaged 64% of peak oxygen consumption (VO2peak). Submaximal VO2levels exceeded 70% of VO2peak in 30% of the subjects. Overall the mean submaximal VO2was 51% higher than VO2levels expected for the speed and grade consistent with severe impairment in economy of gait. There was an inverse relationship between economy of gait and 6MW (r=−0.31,P<0.01) and with the self-selected walking speed (r=−0.35,P<0.01). Thus, the impairment in economy of gait and decreased physiologic reserve result in routine walking being performed at a high percentage of VO2peak.

Exercise Dose and Aerobic Fitness Response in Alzheimer’s Dementia in the FIT-AD Trial

2021 ◽  
Author(s):  
Dereck Salisbury ◽  
Michelle A Mathiason ◽  
Fang Yu
Keyword(s):  
Oxygen Consumption ◽  
Aerobic Exercise ◽  
Cardiorespiratory Fitness ◽  
Cardiopulmonary Exercise Test ◽  
Exercise Group ◽  
Alzheimer’S Dementia ◽  
Peak Oxygen Consumption ◽  
Walking Distance ◽  
Alzheimer's Dementia ◽  
Exercise Dose

The purpose of this study was to examine the effects of a 6-month cycling aerobic exercise intervention on cardiorespiratory fitness and the dose-response relationship in community-dwelling older adults with mild-to-moderate Alzheimer’s dementia. The FIT-AD trial was a single blind, 2-parallel group, pilot randomized controlled trial. The aerobic exercise group participated in a 6-month, thrice weekly, moderate-vigorous intensity cycling intervention while control group performed stretching. Cardiorespiratory fitness was evaluated by peak oxygen consumption from cardiopulmonary exercise test and peak walking distance from the shuttle walk test and 6-minute walk test. Aerobic exercise dose was calculated using the novel heart rate physical activity score. The aerobic exercise group significantly increased peak oxygen consumption (1.28 ml/kg/min; p=.03) in subgroup who achieved maximal criteria on cardiopulmonary exercise test. Changes in peak oxygen consumption and peak walking distance on the shuttle walk and 6-minute walk tests did not significantly differ between aerobic exercise and stretching groups. Notably, the aerobic exercise dose was strongly and significantly correlated to change in peak oxygen consumption (r=.60; n=16; p=.01), in subset who met maximal test criteria. Emphasis on exercise dose is needed in aerobic exercise programs to maximize cardiorespiratory fitness gains in persons with mild-moderate Alzheimer’s dementia.

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