Postexercise reduction in lung diffusion capacity is not attenuated by skin cooling

Area of Science:

• Exercise Physiology
• Pulmonary Function Testing

Background:

• Pulmonary diffusion capacity for carbon monoxide (DLCO) decreases post-maximal exercise, potentially due to interstitial edema and reduced pulmonary capillary blood volume.
• The role of thermal stress in this postexercise DLCO reduction is unclear.

Purpose of the Study:

• To investigate if thermal stress contributes to the postexercise reduction in DLCO.
• To determine if skin cooling can attenuate the postexercise DLCO reduction.

Main Methods:

• DLCO, cutaneous vascular conductance (CVC), mean surface temperature (MST), and rectal temperature were measured before and after maximal incremental cycle exercise.
• Subjects underwent either cold air exposure or a control condition without shivering, with measurements repeated post-intervention.

Main Results:

• DLCO was significantly reduced 90 and 120 minutes after exercise in the control condition.
• Following skin cooling, DLCO remained reduced 90 and 120 minutes post-exercise, despite decreased CVC and MST.
• The reduction in DLCO post-exercise was not significantly influenced by skin surface cooling.

Conclusions:

• The postexercise reduction in DLCO persists even after thermal status is restored.
• Further skin surface cooling does not attenuate the postexercise reduction in DLCO, indicating thermal factors are not the primary drivers.