Why do we sigh?

There are many emotional and personal motivations for heaving a sigh, but what is the physical purpose for it? What is the physiological benefit for inflating your lungs fully, holding for a moment, then releasing all at once? The answer has actually been researched in recent years.


In 2010, researcher in physiology and psychology Elke Vlemincx (and associates) published findings regarding a sigh. Her hypothesis: a reset for the lungs. Respiration is a variable process with many random factors and sometimes when it becomes too regular, the lungs can become less pliable and flexible. By releasing a sigh, she hypothesized, the physiological response is to restart the breathing patterns so that the lungs are loosened up!

To test the hypothesis, she monitored the breathing, heart rates, and blood CO2 levels in 42 people. Over the course of 20 minutes of breathing she discovered…

After a sigh, correlated variability increased. No changes in variability were found in comparable epochs without intermediate sighs. We conclude that a sigh resets structured respiratory variability, enhancing information processing in the respiratory system.

A human lung kept breathing by an "Organ Care System" (made by TransMedics)
A human lung kept breathing by an “Organ Care System” (made by TransMedics)

These findings spurred more research which eventually led to Vlemincx creating a full model on the topic of “Respiratory variability and sighing” in 2012. In this model, not only do sighs reset the lungs they also help regulate emotions. Theoretically, because emotions affect your breathing patterns, by resetting the breathing patterns you can cause a subconscious change in emotion (perhaps Pavlovian?). You can read the model on Science Direct, however they have provided the following highlights:

  • Respiratory variability is not per se respiratory irregularity or instability.
  • Emotion and attention states influence various respiratory variability components.
  • A sigh functions as a resetter in breathing and emotion regulation.
  • A sigh resets normal respiratory variability and induces relief.

Leave a Reply

Your email address will not be published. Required fields are marked *