Abstract
BackgroundMaximal cardiopulmonary exercise testing (CPX) is the gold-standard for cardiorespiratory fitness assessment in chronic heart failure (CHF) patients. However, high costs, required medical supervision, and safety concerns make maximal exercise testing impractical for evaluating mobility-impaired adults. Thus, several submaximal walking protocols have been developed and currently used to estimate peak oxygen consumption (VO2peak) in CHF patients. However, these tests have to be performed at close to maximum exercise intensity. The aim of this study was to examine the validity of a 500-m treadmill-walking test carried out at moderate intensity for estimating VO2peak in community-dwelling adult and elderly patients with CHF and reduced left ventricular ejection fraction (HFrEF).MethodsForty-three clinically stable men with HFrEF (age 67.7 ± 9.2 years, and left ventricular ejection fraction, LVEF 38% ± 6%) underwent exercise testing during an outpatient cardiac rehabilitation/secondary prevention program. Each patients completed a CPX, and a moderate and self-paced (11–13/20 on the Borg scale) 500-m treadmill-walking test. Age, weight, height, walk time, and heart rate during the 500-m test were entered into prediction equations previously validated for VO2peak estimation from a 1000-m walking test in patients with cardiovascular disease and preserved LVEF.ResultsDirectly measured and estimated VO2peak values were not different (21.6 ± 4.9 vs 21.7 ± 4.6 mL/kg/min). The comparison between measured and estimated VO2peak values yielded a correlation of R = 0.97 (SEE = 0.7 mL/kg/min, P < 0.0001). The slope and the intercept coincided with the line of identity (Passing and Bablock analysis, P = 0.50). Residuals were normally distributed, and the examination of the Bland-Altman analysis do not show systematic or proportional error.ConclusionsA moderate and self-regulated 500-m treadmill-walking test is a valid tool for VO2peak estimation in patients with HFrEF. These findings may have practical implications in the context of transitioning from clinically based programs to fitness facilities or self-guided exercise programs in adults and elderly men with HFrEF.
Highlights
Maximal cardiopulmonary exercise testing (CPX) is the gold-standard for cardiorespiratory fitness assessment in chronic heart failure (CHF) patients
Participants 43 consecutive medically stable male outpatients with heart failure and reduced left ventricular dysfunction (HFrEF) (LVEF ≤45%), aged 35 to 83 yrs. (67% over 65 yrs), classified as New York Hear Association (NYHA) class I-II are included in the study
Statistical analyses were performed using the package Medcalc 16.2 software (Ostende, Belgium). Both the CPX and the 500-m treadmill-walking tests were completed by all subjects without complications
Summary
Maximal cardiopulmonary exercise testing (CPX) is the gold-standard for cardiorespiratory fitness assessment in chronic heart failure (CHF) patients. Several submaximal walking protocols have been developed and currently used to estimate peak oxygen consumption (VO2peak) in CHF patients These tests have to be performed at close to maximum exercise intensity. Walking tests of varying distance and times are commonly used to assess exercise tolerance in various clinical conditions (including CHF) These tests have to be performed at an intensity close to maximum. Daily activities rarely require maximal effort, and the ability to perform sustained submaximal exercise is an important component of health-related fitness assessment In this respect, examination of submaximal exercise capacity can be useful to functionally evaluate patients and for developing appropriate exercise prescriptions, adjusting the medical regimen, and identifying the need for further diagnostic interventions [9]
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