Sex-Based Differences in Peak Oxygen Uptake Among Individuals with Heart Failure: Systematic Review and Meta-Analysis.

Abstract

Background: Heart failure (HF) studies examining peak oxygen uptake (VO₂) have largely focused on males, leaving a significant gap in understanding of the magnitude and the mechanisms underpinning the impairment in females with HF. The objective of this systematic review and meta-analysis is to examining sex differences in peak VO₂ in HF. Methods: Studies were found through Medline, EMBASE, Scopus, CINAHL and SPORTDiscus and included if they compared peak VO₂ in males and females with HF. Data extraction and methodological quality assessment were completed by two independent coders. Main outcomes and measures included peak VO₂ (ml/kg/min, primary outcome) and its Fick determinants (secondary outcome). The weighted mean difference (WMD) was calculated for each outcome between females and males. Results: After screening 1,579 articles, 33 studies were included. Peak VO₂ was lower in females versus males (n=20,115, WMD: -2.1 ml/kg/min, 95% CI: -2.4 to -1.8 ml/kg/min). In studies reporting the Fick determinants, peak exercise cardiac output (n=1,219, WMD: -1.3 l/min, 95% CI: -1.7 to -1.0 l/min), stroke volume (n=1,151, WMD: -15.2 ml, 95% CI: -18.8 to -11.7 ml), and arterial-venous oxygen difference (n=1,131, WMD: -1.4 ml/dl, 95% CI: -2.3 to -0.5 ml/dl) were lower while peak heart rate was higher compared to males (n=10,103, WMD: 2.4 beats/min, 95% CI: 0.1 to 4.7 beats/min). Conclusions: The greater peak VO₂ impairment among females with HF is likely due to lower peak exercise cardiac output and arterial-venous oxygen difference. Future research should prioritize interventions aimed at addressing these physiological constraints in females with HF.