Sighs May Ease Breathing by Reducing Lung Fluid Surface Tension, Study Finds

A new study suggests that the sense of relief felt after a sigh may be linked to how lung movements during deep breaths reduce the surface tension of lung fluid, making breathing easier.

Researchers, including scientists from ETH Zurich, Switzerland, conducted laboratory experiments to observe how lung fluid behaves when stretched and compressed. The findings indicate that the natural inhalation and exhalation movements of the lungs subject the fluid to similar stresses, helping to relieve tension.

The study provides insights into the physiological role of sighing, explaining why a deep breath can create a feeling of relaxation and improved airflow in the lungs.