How Do Sex and Cardiorespiratory Fitness Impact Pulmonary Diffusing Capacity?

Area of Science:

• Physiology
• Exercise Science

Background:

• Pulmonary diffusing capacity (DLCO) is influenced by non-modifiable factors like biological sex and modifiable factors such as cardiorespiratory fitness.
• The combined and interactive effects of these factors on DLCO are not well-documented.

Purpose of the Study:

• To investigate the independent and combined associations of biological sex and cardiorespiratory fitness (V̇O2peak) with DLCO and its determinants.
• To analyze these associations at rest and during exercise, controlling for lung size (VA).

Main Methods:

• Retrospective analysis of data from 113 participants (57 female).
• Utilized general linear regression and linear mixed effects modeling.
• Evaluated DLCO, capillary blood volume (VC), and membrane diffusing capacity (DM) adjusted for hemoglobin and lung size.

Main Results:

• At rest, only sex remained significantly associated with DLCO after accounting for lung size; V̇O2peak was associated with resting VC.
• During exercise, DLCO was associated with sex but not V̇O2peak after accounting for lung size.
• A significant interaction effect was found for exercise DLCO and VC, indicating that higher V̇O2peak enhances DLCO, particularly in trained males compared to trained females.

Conclusions:

• The response of DLCO during exercise is significantly modified by the interplay of biological sex and cardiorespiratory fitness.
• These findings highlight the complex interactions influencing pulmonary gas exchange during physical exertion.