Circadian System Plays Role in Asthma Severity

A new study explores why individuals who suffer most from the condition have the worse symptoms at night.

The circadian system plays a key role in contributing to the worsening of asthma severity, according to the results of a new study conducted by Brigham Women’s Hospital and Oregon Health & Science University.

“We observed that those people who have the worst asthma in general are the ones who suffer from the greatest circadian-induced drops in pulmonary function at night and also had the greatest changes induced by behaviors, including sleep,” Steven Shea, PhD, professor and director at Oregon Institute of Occupational Health Sciences, said in a statement. “We also found that these results are clinically important because, when studied in the laboratory, symptom-driven bronchodilator inhaler use was as much as four times more often during the circadian night than during the day.”

Many factors, such as air temperature, exercise posture, and sleep environment, have linked to asthma severity. The circadian system is critical for bodily functions and anticipating the daily cycling environmental and behavioral demands.

Individuals were kept to a “constant routine” where their bronchodilator use was assessed.

The study focused on 17 individuals with asthma who were not on steroids but did use bronchodilator inhalers when necessary. The study participants spent 38 hours awake in a constant posture with identical snacks every 2 hours. The individuals, then, underwent a 28-hour sleep/wake cycle. Both cycles were under dim lights, and asthma symptoms, bronchodilator use, and lung function were assessed periodically.

Reference

Study explores why asthma worsens at night. EurekAlert. News release. September 6, 2021. Accessed September 7, 2021. https://www.eurekalert.org/news-releases/927183