Asthma sufferers generally find their condition gets worse at night. Now, a research group may understand why.
In a new study from Tohoku University, researchers found melatonin, a sleep hormone that is sometimes prescribed to treat insomnia, exasperates the constriction of the bronchus—the pathway that moves air to and from the lungs.
Patients with asthma often experience a worsening of asthmatic symptoms at night in so-called “nocturnal asthma.”
Previous research found more than 50% of asthma deaths occur at night, exposing a link between nocturnal asthma symptoms and asthma deaths.
In the study, the team discovered that melatonin, a sleep hormone, worsens asthma.
Asthma patients suffer from bronchoconstriction, where the smooth muscles of the bronchus—the pathway that moves air to and from your lungs—contract.
To ease this, many take a bronchodilator, a medicine that widens the bronchus.
However, melatonin, which is often prescribed for insomnia, favors a state of bronchoconstriction and weakens the relaxing effect of a bronchodilator through the activation of the melatonin MT2 receptor.
To elucidate this, the research group identified the expression of the melatonin MT2 receptor in human airway smooth muscle.
They found that the activation of the melatonin MT2 receptor with higher doses of melatonin greatly potentiated bronchoconstriction.
Furthermore, melatonin attenuated the relaxing effects of the widely used bronchodilator β-adrenoceptor agonist.
The team says although serum concentration of melatonin did not significantly induce airway constriction, greater doses of melatonin, which is clinically used to treat insomnia, jet lag, or cancer, worsened asthma symptoms.
If you care about sleep, please read studies about treatment that could reduce severity of sleep apnea by one third, and sleep problem that could increase risk of sudden death, high blood pressure.
For more information about health, please see recent studies about why people with sleep apnea more likely to have high blood pressure, and results showing this common sleep issue may be a big risk factor of COVID-19.
The study is published in the American Journal of Physiology-Lung Cellular and Molecular Physiology. One author of the study is Kentaro Mizuta.
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