Study explores why asthma worsens at night

For hundreds of years, people have observed that asthma severity often worsens in the nighttime. One longstanding question has been to what degree the body's internal circadian clock -- as opposed to behaviors, such as sleep and physical activities -- contributes to the worsening of asthma severity. Using two circadian protocols, investigators from Brigham and Women's Hospital and Oregon Health and Science University have pinned down the influence of the circadian system, uncovering a key role for the biological clock in asthma. Understanding the mechanisms that influence asthma severity could have important implications for treating asthma.