There are many reasons why people with asthma may experience asthma symptoms at night. The body's natural rhythm certainly plays a role, with certain hormones being at their highest (or lowest) in the early morning. Some of these, such as melatonin, increase inflammation in the airways.
For people with asthma, the number of inflammatory cells in the airways is highest in the early morning, with a peak at 4 AM. In addition, all people with asthma experience reduced lung function overnight. In one study, however, patients with nocturnal asthma were found to have a 20% decrease in lung function overnight compared with 4% in non-asthmatics.
In addition to the body's own role in contributing to nocturnal asthma, other causes include:
- Exposure to asthma triggers in bed, such as dust mites or pet dander
- Delayed response to a trigger exposed to earlier in the day
- Sinus problems and post-nasal drip (mucus dripping into the airways when lying down)
- Gastroesophageal reflux disease (GERD)
- Bronchospasm induced by decreased body temperature
- Once-daily asthma medications wearing off in the early morning hours
- Sleep apnea, which is a short episode of suspended breathing that can be caused by an airway obstruction or an abnormal brain signal
Treatment and Prevention
Because nocturnal asthma can significantly disrupt nighttime sleep, which can result in a decreased ability to function during the day, it is well worth identifying the specific causes and finding the best treatment.
Prevention methods include ridding the bedroom of allergy triggers, doing an inventory of daytime exposures that may be causing a delayed reaction, and adequately treating sinus problems and post-nasal drip. Treatment may include environmental changes, different asthma medications, and sometimes the diagnosis of related conditions, which can then be properly addressed.
If poor nighttime asthma control is believed to be caused by asthma medications wearing off too early, changing the timing or dosage of the medications may improve symptoms one experiences at night. For example, using a once-daily inhaler in the evening instead of using it in the morning may cause it to continue to work throughout the night.
Many different asthma medications have been specifically studied for their effectiveness at night. Long-acting beta agonists, such as Serevent (salmeterol), have been found to improve symptoms when used twice a day.
Slo-bid (theophylline), a slow-release drug, has also been effective in relieving nighttime asthma symptoms when taken once in the late afternoon. Inhaled steroids and leukotriene modifiers may also play a helpful role. Steroid pills, such as prednisone, have been shown to decrease nighttime airway obstruction and inflammation, particularly when taken at 3 PM.
There is some controversy about the relationship between GERD and nocturnal asthma. There is an association between reflux of stomach acids into the esophagus and constriction of the airways. However, the results of studies designed to improve nighttime asthma by treating GERD with proton pump inhibitors, such as Prilosec (omeprazole), have been mixed.
Obstructive sleep apnea (OSA for short) is another condition that may play a role in nighttime breathing problems and poor sleep quality. People with OSA have multiple overnight episodes in which they stop breathing during sleep due to an obstruction of the airway caused by the relaxation of the mouth and throat. It was discovered that 48% of people who snore and have nocturnal asthma also have OSA. It may sometimes be difficult to differentiate OSA from nocturnal asthma, as they can both cause disruptions in breathing and even low oxygen levels.
The treatment for OSA, for both those who have asthma and those who don't, is continuous positive airway pressure (CPAP), which forces air into the lungs through a mask that fits over the nose or mouth and is worn during sleep. Studies have shown that people with asthma who also have OSA can improve their nighttime symptoms by using CPAP, although it is unclear if its use also improves lung function.
It is important to be tested for OSA, particularly for those people who are overweight and have uncontrolled asthma. The diagnosis and treatment of nocturnal asthma can be challenging. Anyone whose nighttime asthma is significantly impacting quality of life should ask a doctor what can be done to help get his or her asthma under better control.
Related Articles
- What You Need to Know About Asthma
- How to Talk With Your Doctor About Your Nocturnal Symptoms
- Why You Should Consult a Specialist
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