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Updated: Jun 18, 2026

Dual Test Gas Pulmonary Diffusing Capacity Measurement During Exercise in Humans Using the Single-Breath Method
Published on: February 2, 2024
Pulmonary diffusion and aerobic capacity: is there a relation? Does obesity matter?
G S Zavorsky1, B Wilson, J K Harris
1Department of Obstetrics, Gynecology and Women's Health, Saint Mary's Health Center, Saint Louis University, MO 63117, USA. zavorsky@slu.edu <zavorsky@slu.edu>
Pulmonary diffusing capacity for nitric oxide (DLNO) better predicts peak aerobic capacity (VO2peak) than DLCO or Vc in both fit and obese individuals. DLNO is recommended for its ease of measurement and stronger correlation with VO2peak.
Area of Science:
- Cardiopulmonary Physiology
- Exercise Science
Background:
- Peak aerobic capacity (VO2peak) is a key indicator of cardiorespiratory fitness.
- Pulmonary diffusing capacity, measured by DLNO and DLCO, reflects gas exchange efficiency.
Purpose of the Study:
- To determine if resting pulmonary diffusing capacity (DLNO, DLCO, Vc) predicts VO2peak.
- To identify which measure of pulmonary diffusion best predicts VO2peak.
Main Methods:
- Thirty-five extremely obese and 26 fit non-obese individuals participated.
- Resting DLNO and DLCO were measured.
- Subjects underwent graded exercise testing to determine VO2peak.
Main Results:
- Resting DLNO predicted VO2peak in both fit and obese groups.
- Resting DLCO predicted VO2peak only in fit individuals.
- DLNO demonstrated a stronger predictive relationship with VO2peak compared to DLCO or Vc.
Conclusions:
- Resting pulmonary diffusion, particularly DLNO, is a significant predictor of VO2peak.
- DLNO is recommended as a preferred measure due to its ease of collection and robust correlation with VO2peak.
- The relationship between pulmonary diffusion and VO2peak differs between fit and obese individuals.
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