Purpose: A significant discrepancy between measured oxygen consumption (VO(2)) (via ventilatory expired gas analysis) and estimated VO(2) (via the imposed workload) frequently is reported in the heart failure (HF) population during symptom-limited exercise testing. The purpose of this investigation was to examine the difference between measured and estimated VO(2) (VO(2) discrepancy) during a highly conservative ramping protocol.
Methods: For this study, 28 subjects with compensated HF (20 men and 8 women; age, 51.1 +/- 14.6 years) and 19 healthy control subjects (age-, gender-, and activity-matched to an HF subgroup) underwent symptom-limited exercise testing (treadmill) with ventilatory expired gas analysis.
Results: Peak estimated and measured VO(2) values were significantly higher in the age-, gender-, and activity-matched control group than in the HF group, but the change in measured VO(2) per change in estimated VO(2) (Deltameasured/Deltaestimated VO(2) slope) and the VO(2) discrepancy did not reach statistical significance. Peak estimated VO(2) was a significant predictor of peak measured VO(2) in the overall HF group (R2 = 0.90; P <.001).
Conclusions: Although estimated VO(2) is not considered a replacement for measured VO(2), these results indicate that a highly conservative exercise protocol may allow for a more accurate prediction of peak measured VO(2) via the estimated oxygen cost for a given workload in patients with compensated HF.
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http://dx.doi.org/10.1097/00008483-200305000-00004 | DOI Listing |
Sci Rep
January 2025
Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, 119991, Russia.
Vanadium dioxide ([Formula: see text]) is a favorable material platform of modern optoelectronics, since it manifests the reversible temperature-induced insulator-metal transition (IMT) with an abrupt and rapid changes in the conductivity and optical properties. It makes possible applications of such a phase-change material in the ultra-fast optoelectronics and terahertz (THz) technology. Despite the considerable interest to this material, data on its broadband electrodynamic response in different states are still missing in the literature.
View Article and Find Full Text PDFFront Sports Act Living
January 2025
Graduate School of Health and Sports Science, Juntendo University, Inzai, Japan.
Introduction: Marathon running has become increasingly popular among amateur athletes, many of whom maintain speeds of 8-9 km/h. However, existing methods for estimating oxygen consumption (VO) during running and walking-such as the American College of Sports Medicine (ACSM) equations and commercial activity monitors-often lack accuracy and transparency. This study introduces the Hata-Yanagiya Physical Activity Calculation (HYPAC) system, a novel approach for estimating VO using Global Positioning System (GPS) and map data.
View Article and Find Full Text PDFFront Physiol
January 2025
Department of Sports, Physical Education and Outdoor Studies, University of South-Eastern Norway, Kongsberg, Norway.
Purpose: To explore the relationships between performance variables and physiological variables in a short-time (2-3 min) cycling time trial (TT) on a cycle ergometer.
Methods: Fifteen young elite cyclists (age: 17.3 ± 0.
Rev Port Cardiol
January 2025
Cardiology Department, Santa Cruz Hospital, Lisbon, Portugal; Cardiac Rehabilitation Unit, Santa Cruz Hospital, Lisbon, Portugal.
Introduction And Objectives: Cardiopulmonary exercise testing (CPET) is the gold standard for quantifying aerobic functional capacity, yet it is costly and not widely available. The CLINIMEX Aerobic Fitness Questionnaire (C-AFQ) may be a practical alternative as it estimates oxygen consumption at peak exercise (VO peak) based on patients' responses to a list of activities with known energy requirements. However, its applicability in cardiac patients is unclear and has not yet been studied.
View Article and Find Full Text PDFAnn Intensive Care
January 2025
Department of Intensive Care Medicine, Universitaire Ziekenhuis Brussel (UZ Brussel), Vrije Universiteit Brussel (VUB), Brussels, Belgium.
Background: Continuous veno-venous hemodiafiltration (CVVHDF) is used in critically ill patients, but its impact on O₂ and CO₂ removal, as well as the accuracy of resting energy expenditure (REE) measurement using indirect calorimetry (IC) remains unclear. This study aims to evaluate the effects of CVVHDF on O₂ and CO₂ removal and the accuracy of REE measurement using IC in patients undergoing continuous renal replacement therapy.
Design: Prospective, observational, single-center study.
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