A summary of research published in ERJ Open Research.
Breathlessness is an uncomfortable feeling that people living with a lung condition may experience, as well as during physical activity. It is sometimes described as shortness of breath or dyspnoea. It can be distressing and can have an impact on daily life.
Breathlessness is not caused only by how the lungs work. Previous research suggests that it may also be influenced by how the brain processes signals coming from the airways and chest.
Menthol is a natural substance found in mint oils. It produces a cooling sensation and is commonly used to make breathing feel easier, such as during cold and flu. Earlier studies have shown that menthol can reduce the feeling of breathlessness, even when it does not change breathing patterns or oxygen levels. However, it has not been clear how menthol produces this effect.
Researchers invited 30 healthy adults to complete four short breathing sessions. The aim was to understand how menthol reduces breathlessness and whether it works by affecting the brain or changing breathing itself.
During each session, participants were asked to breathe against resistance. This is a safe and well-established way of creating the sensation of breathlessness in a controlled laboratory setting. In two sessions, participants inhaled menthol. In the other two sessions, they inhaled a strawberry scent, which was used as a placebo.
While participants were breathing, the researchers measured:
This allowed the researchers to examine whether menthol mainly affected the brain or the lungs.
When participants inhaled menthol, they reported that their breathlessness felt less intense and unpleasant than when they inhaled the strawberry scent. Specific sensations, including air hunger and the feeling of having to concentrate hard on breathing, were also reduced.
Measurements of brain activity showed that menthol reduced the brain’s response to breathing‑related sensory signals. This suggests that the brain processed these signals as less strong or less threatening. In contrast, there were no meaningful changes in breathing patterns.
The results show that menthol reduced breathlessness without changing how participants breathed. This indicates that menthol mainly affected how the brain processed breathing sensations, rather than acting directly on the lungs or breathing muscles.
Breathlessness is often difficult to treat and can have a major impact on quality of life. This study helps to explain how menthol can make breathing feel easier.
Menthol inhalation is simple, low cost and non‑invasive, which makes it an accessible option for symptom relief. The findings also support further research into using menthol or similar sensory approaches to help people with long‑term respiratory conditions, such as chronic obstructive pulmonary disease (COPD), where breathlessness is a major daily challenge.
Read the original research paper: Menthol inhalation relieves dyspnoea through the brain
