What this means
Lean body mass (LBM) strongly associates with the capacity to deliver and consume oxygen in pilot studies performed in adults with low LBM. We aimed to test whether LBM generally accounts for the phenotype of the circulatory system and hence its sex dimorphism in humans.
A plain-English summary is on its way. Until then, this is the start of the authors' own summary.
- Who it was tested in
- Not stated
- Kind of research
- A study
The science
- Original title
- Lean Body Mass Accounts for the Sex Dimorphism of the Circulatory System and Aerobic Exercise Capacity in Humans.
- Authors
- Liu X, Guo M, Montero D
- Journal
- Sports medicine (Auckland, N.Z.)
- Published
- Oct 27, 2026
- Study type
- Study
- PMID
- 42934389 ↗
Abstract
Background
Lean body mass (LBM) strongly associates with the capacity to deliver and consume oxygen in pilot studies performed in adults with low LBM. We aimed to test whether LBM generally accounts for the phenotype of the circulatory system and hence its sex dimorphism in humans.
What they did
Healthy women and men (n = 294, 50% female) matched by age and physical activity throughout the adult lifespan (aged 18-78 years) were included. Body composition (dual-energy X-ray absorptiometry), hemoglobin mass/intravascular volumes (carbon monoxide rebreathing), cardiac structure/function/hemodynamics (ultrasound, continuous blood pressure), and aerobic exercise capacity (cycle ergometry, metabolic cart, power meter) were assessed in standardized conditions. Linear regression analyses assessed the relationship of LBM with study variables in each sex. Sex comparisons were performed in non-LBM-matched (n = 294) and LBM-matched (n = 70) individuals.
What they found
Lean body mass linearly associated with the majority of hematological, hemodynamic, cardiac, and exercise capacity variables in women and men. The slopes of the regression lines did not differ between sexes, with women falling in the lower and men in the upper range of the overall relationship of LBM with these variables. Accordingly, in non-LBM-matched individuals, marked sex differences were observed in >90% of variables. In LBM-matched individuals, no cardiac-related variable (left ventricular structure and function, blood pressure, systemic vascular resistance, aerobic capacity) differed between women and men. Cardiac structure and function, blood pressure, vascular resistance, and aerobic exercise capacity are statistically accounted for by LBM in humans, irrespective of sex. The sex dimorphism of the circulatory system strongly associates with the metabolically active mass, rather than sex.
The authors' abstract, grouped under plain headings from its own section labels.
Liu X, Guo M, Montero D Lean Body Mass Accounts for the Sex Dimorphism of the Circulatory System and Aerobic Exercise Capacity in Humans. Sports medicine (Auckland, N.Z.). 2026. doi:10.1007/s40279-026-02552-y. PMID: 42934389. https://pubmed.ncbi.nlm.nih.gov/42934389/