Silva RN; Division of Respiratory and Critical Care Physiology and Medicine, Harbor-UCLA Medical Center, Torrance, CA, USA.
Porszasz J; Ferguson C; Rehder-Santos P;Roscani MG; de Oliveira CR; Catai AM; Stringer WW; Borghi-Silva A;
European journal of applied physiology [Eur J Appl Physiol] 2025 Aug 05.
Date of Electronic Publication: 2025 Aug 05.
Exercise intolerance is a cardinal symptom in patients with heart failure (HF), and cardiopulmonary exercise testing (CPET) is the gold standard method for its assessment. The treadmill and cycle ergometers (upright and recumbent) are used in clinical practice for tracking disease progression and risk stratification, therefore, understanding the physiological differences related to ergometer is important. The aim of this study was to compare the physiological responses to exercise on treadmill and recumbent cycle ergometer in patients with HF with reduced ejection fraction (HFrEF) using a linear ramp protocol matched with controlled work rate (WR) profiles. Thirteen patients with HFrEF (left ventricular ejection fraction: 34.5% [28.7-47%]) were included. They performed two randomized ramp-incremental CPETs, on recumbent cycle and treadmill, both with incrementation rates of 10 watts per minute (W/min). The cardiorespiratory data obtained in both tests were WR-aligned and iso-WR responses were compared. Patients reached similar WR peak on both exercise modalities (84 ± 23 vs 91 ± 26 watts, P = 0.133, for recumbent cycle and treadmill, respectively) with no differences in ventilatory efficiency ( INLINEMATH / INLINEMATH CO 2 slope) (30.8 ± 4.7 vs 30.9 ± 7.3, P = 0.981). However, exercising on recumbent cycle resulted in lower peak oxygen uptake ( INLINEMATH O 2 ) (13.4 [11.3-15.9] vs 15.8 [14.7-18.4] mL/kg/min, p = 0.002) and higher Weber HF severity classification (p = 0.034). Considering the higher INLINEMATH O 2 peak reached and its role in clinical decision-making-despite similar INLINEMATH / INLINEMATH CO 2 slope between ergometers-treadmill should be considered the optimal ergometer for exercise intolerance and risk stratification assessment in patients with HFrEF, since it reflects a more accurate exercise capacity and disease severity.
Competing Interests: Declarations. Conflict of interest: The authors declare no conflicts of interest. Financial support: Rebeca Nunes Silva reports financial support for the present study from Coordination for the Improvement of Higher Educational Personnel (CAPES), Brazil (CAPES 001 – PhD Scholarship; CAPES PrInt – Program #6685). Janos Porszasz receives royalty payments from a CPET book from Wolters Kluwer. Carrie Ferguson is supported by grants from NIH (R01HL166850; 5UH3HL155798). She is involved in contracted clinical research with United Therapeutics, Genentech, Regeneron, Respira Therapeutics and Mezzion. She reports consulting fees from Respira Therapeutics. She is a visiting Associate Professor at the University of Leeds, UK. Patrícia Rehder-Santos has no research funding to declare. Meliza Goi Roscani reports financial support from São Paulo Research Foundation (FAPESP) (Grants #2021/05231–7 and #2023/04876–0). Claudio Ricardo Oliveira has no research funding to declare. Aparecida Maria Catai is supported by the National Council for Scientific and Technological Development (CNPq – level 1A Research Fellow, #310,612/2019–5) and receives financial support from FAPESP (#2016/22215-7). William Stringer is involved in contracted clinical research with Genentech, Regeneron, Roche, AstraZeneca and the NIH Recover-Vital and Recover-Neuro clinical trials. He performs CPET Data Center activities for the NIH funded PETRACT study (UG3HL155798-01A1). He is a co-investigator on an NIH Small Business Innovation Award (1R43HL167289-01) and has been a site PI for the NIH RETHINC (5U01HL128954‐04) and BLOCK-COPD (W81XWH-15–1-0705) studies. He performs Data Safety Monitoring Board activities for SYNEOS and CAPRICOR. He receives royalty payments from a CPET book from Wolters Kluwer. He is a paid consultant for Genentech, Verona and Regeneron. He owns stock in HIA. Audrey Borghi-Silva is involved in research grants from FAPESP (Grant #2015/26/501–1), CAPES-Brazil (CAPES-001), and CNPq-Brazil (Grant #201,157/2024–1) with national and international collaboration. Audrey Borghi-Silva is an established Investigator (level 1B) of CNPq. Currently, she is advisor of the scientific board of FAPESP.