Many asthmatics see their asthma worsen at night. Researchers have just figured out why.
- 50% of asthma deaths occur at night.
- Asthma is characterized by the occurrence of attacks which are episodes of respiratory discomfort (dyspnea) wheezing (wheezing). In some cases, coughing may be the only symptom.
Melatonin exacerbates asthma, says a new study published in the American Journal of Physiology Lung Cellular and Molecular Physiology. This explains why the condition of people with asthma often worsens at night, a hitherto mysterious phenomenon.
Increased bronchoconstriction
Melatonin is a hormone that naturally induces sleep. Researchers have also found that it promotes transient narrowing of the lower airways (or bronchoconstriction), and therefore asthma attacks. More precisely, the scientists observed that it was the activation of the MT2 receptor for melatonin which was at the origin of this mechanism.
“Although serum melatonin concentration did not significantly induce airway constriction, larger doses of melatonin, which are used clinically to treat insomnia, jet lag management, or cancers, worsened asthma symptoms and impaired the therapeutic effect of bronchodilators”, said study director Kentaro Mizuta, of the Graduate School of Dentistry (Tohoku University).
Block MT2 receiver
Haruka Sasaki, co-author of the research, added: “pharmacological therapy that blocks the MT2 receptor for melatonin could inhibit the adverse effects of melatonin on the airways.” Asthma affects around 4 million people in France and causes around 900 deaths every year.
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