Nighttime (Nocturnal) Asthma
Sleep disturbances due to asthma are common: up to 75% of asthma patients report having symptoms at night.1 Waking up due to asthma is sometimes called “nighttime asthma” or “nocturnal asthma.” Experts do not know whether this is a separate type of asthma or just a sign of more severe asthma.2
Either way, your quality of life suffers if you are waking up frequently because of asthma symptoms. Children with nighttime asthma symptoms miss more school, and their parents miss more work.3 They use more medications and visit the doctor more often.4
What causes nighttime/nocturnal asthma?
Lung function changes throughout the day for people with healthy lungs. Lung function is at its best around 4 pm and at its lowest around 4 am.
People with nighttime asthma usually have lower lung function overall, and the difference in lung function between day and night is greater than normal.2 Your health care provider may want to evaluate changes in lung function throughout the day in order to make a diagnosis.5 This step is also important for monitoring how effective treatments are.5
The cause of wide fluctuations in lung function is not clear. Some studies have shown that people with nocturnal asthma have more inflammation at night.2 They also have more airway and lung resistance. More airway resistance means that it is harder for air to get in and out of the lungs.
What conditions overlap with nighttime/nocturnal asthma?
GERD: Many people with asthma have gastroesophageal reflux disease, also called GERD.6 Reflux at night can contribute to nighttime asthma symptoms. Studies have shown that people who took medication for GERD have fewer nocturnal asthma symptoms, fewer asthma attacks, and better quality of life.
Sleep apnea: Obstructive sleep apnea and asthma are separate diseases with similar symptoms. Some people have both diseases. It is difficult, but important, to make the right diagnosis. Different treatments are used for the two conditions.6
Obesity: Being very overweight may have a role in nighttime asthma symptoms.2 People with asthma who lost a lot of weight were studied. The results showed that the gap between daytime and nighttime lung function got smaller after people lost weight.
How frequent is too frequent?
In one study, even waking up just one to three nights per month had a negative effect on school performance and attendance.3 The frequency of nighttime awakenings is one factor used to classify asthma severity, as shown in Table 1.6
Table 1. Frequency of Nighttime Awakening and Asthma Severity
How is nighttime/nocturnal asthma treated?
The frequency of nighttime awakenings is one indication of how well your medications are controlling your asthma, as shown in Table 2.6 One goal of treatment is to eliminate nocturnal symptoms.
Table 2. Frequency of Nighttime Awakening and Asthma Control
Adapted from National Heart, Lung, and Blood Institute. Expert panel report 3 (EPR-3): Guidelines for the diagnosis and management of asthma - Full Report 2007. Figures 3–5a, b, c, pgs 75-77.
Treatment for people with nighttime asthma follows the steps for long-term asthma management. In studies, use of asthma control medications improved nocturnal symptoms.2 If you are waking up frequently, it may be necessary to talk with your health care provider about adjusting your asthma medication.6