Nocturnal asthma, with symptoms like chest tightness, shortness of breath, cough, and wheezing at night, can make sleep impossible and leave you feeling tired and irritable during the day. These problems may affect your overall quality of life and make it more difficult to control your daytime asthma symptoms.
The chances of experiencing asthma symptoms are higher during sleep. Nocturnal wheezing, cough, and trouble breathing are common yet potentially dangerous. Many doctors often underestimate nocturnal asthma or nighttime asthma.
Studies show that most deaths related to asthma symptoms such as wheezing occur at night.
Nocturnal Asthma Causes
The exact reason that asthma is worse during sleep are not known, but there are explanations that include increased exposure to allergens; cooling of the airways; being in a reclining position; and hormone secretions that follow a circadian pattern. Sleep itself may even cause changes in bronchial function.
During sleep, the airways tend to narrow, which may cause increased airflow resistance. This may trigger nighttime coughing, which can cause more tightening of the airways. Increased drainage from your sinuses can also trigger asthma in highly sensitive airways. Sinusitis with asthma is quite common.
Asthma problems may occur during sleep, despite when the sleep period is taking place. People with asthma who work on the night shift may have breathing attacks during the day when they are sleeping. Most research suggests that breathing tests are worse about four to six hours after you fall asleep. This suggests there may be some internal trigger for sleep-related asthma.
Lying in a reclining position may also predispose you to nighttime asthma problems. Many factors may cause this, such as accumulation of secretions in the airways (drainage from sinuses or postnasal drip), increased blood volume in the lungs, decreased lung volumes, and increased airway resistance.
Breathing colder air at night or sleeping in an air‑conditioned bedroom may also cause loss of heat from the airways. Airway cooling and moisture loss are important triggers of exercise‑induced asthma. They are also implicated in nighttime asthma.