Dr. Jorge Jaber, 12/03/2003
Melatonin, a hormone secreted by the pineal gland in the brain, is an important regulator of circadian rhythms in the body, especially sleep. It is released at night, generally beginning in the evening hours before bedtime, peaking in the middle of the night, and ending about the time people awaken. Because of its association with sleep, over-the-counter melatonin has become a popular dietary supplement sold as a treatment for jet lag and insomnia.
However, melatonin has also been shown to enhance inflammation in cell and animal studies of asthma. Airway inflammation is one reason people with asthma have difficulty breathing. A significant portion of asthma patients experience increased symptoms at night. Dr. Sutherland and his colleagues hypothesized that melatonin may play a role in this nighttime worsening of asthma.
The researchers had seven people with nocturnal asthma, 13 with non-nocturnal asthma, and 11 healthy controls establish a regular sleep schedule for seven days. On the eighth night, small blood samples were taken from the sleeping patients every two hours. These samples were evaluated for their melatonin levels. The study subjects also performed lung function tests before going to bed and after waking up.