Sighing: An Overlooked Respiratory Reflex in Pulmonary Physiology and Emotional Regulation

By: Nesredin Hassen Yesuf

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Introduction

Sighing is something we all do. Often, we do not think about it. It is a deep breath in and a long breath out. We usually sigh when we feel relieved, frustrated, or tired. Sighing also helps keep our lungs working properly. Even though we sigh all the time, scientists are still learning exactly how important it is. Sighing connects how our lungs work to how we feel.

Understanding sighing helps us see how the body keeps the lungs healthy and responds to emotional events.

How Sighing Works

A sigh is a breath that is deeper than a normal breath. It is about twice as deep as a typical breath. Special parts of the brain, located in the brainstem, trigger this deeper breath [1].

Figure 1: Physiological sigh

When we sigh, it helps keep the tiny air sacs (alveoli) in our lungs from collapsing. During normal, shallow breathing, some of these air sacs can slowly deflate. A sigh stretches the lungs and pops these air sacs back open, which keeps the lungs working well [2].

What Controls Sighing

Sighing is controlled by both automatic body processes and our emotions. Specific nerve circuits in the brain act as “helpers” that make us sigh [1]. This shows that sighing is not random—it is something the body does on purpose to maintain healthy lungs.

The brain also links sighing to our emotional state. That is why we sigh more often when we are stressed, anxious, or frustrated [3].

What Sighing Does

Sighing helps the lungs and regulates our feelings.

For the lungs, sighing keeps them working efficiently. It helps us exchange oxygen better. Without an occasional sigh, parts of our lungs would slowly collapse, making breathing less effective [2].

For our feelings, sighing helps us feel better. A deep sigh can signal the body to calm down during stress, creating a sense of relief. This shows that sighing supports both physical and emotional health [3].

Clinical Importance

Some people sigh too little or too much. If we do not sigh enough, part of the lungs may not work well because collapsed air sacs stay closed. If we sigh very frequently, it can be a sign of anxiety or a breathing disorder.

In hospitals, doctors use breathing machines (ventilators) to help patients breathe. These machines often deliver a special “sigh” breath—a larger volume of air at intervals—to help keep the air sacs open and prevent lung injury, mimicking the body’s natural sigh.

Sighing is not just something we do when we feel a certain way. It is a vital action that keeps our lungs healthy and helps us manage emotions. It shows how our body and feelings are deeply connected. Learning more about sighing helps us understand more about our lungs and our emotional well-being.

References

1. Li P, Janczewski WA, Yackle K, Kam K, Pagliardini S, Krasnow MA, Feldman JL. The peptidergic control circuit for sighing. Nature. 2016;530(7590):293–297. https://doi.org/10.1038/nature16964⁠

2. Severs LJ, Vlemincx E, Ramirez JM. The psychophysiology of the sigh: I. The sigh from the physiological perspective. Biol Psychol. 2022;170:108313. https://doi.org/10.1016/j.biopsycho.2022.108313⁠

3. Boiten FA. The effects of emotional behaviour on components of the respiratory cycle. Biol Psychol. 1998;49(1–2):29–51. https://doi.org/10.1016/S0301-0511(98)00025-8

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