Why do asthma symptoms gets worse at night?

Asthma is the inflammation of the airways and affects people of all ages. Allergens and other environmental factors attack bronchial walls resulting in hypersensitive reactions which cause swelling and narrowing of the lower respiratory tract. At night, the asthmatic symptoms get worse. This night-time asthma is also called Nocturnal asthma. It is also a reason for deaths in asthmatic patients due to exacerbation of symptoms. It can occur more than once a month.

Symptoms of nocturnal asthma

Nocturnal asthma and regular asthma have almost the same symptoms, but few become severe at night in nocturnal asthma which includes:

  • Sleeplessness
  • Wheezing
  • Chest tightness
  • Coughing

In addition, many sleeping issues occur in children and people of old age.

  • Excessive daytime sleepiness
  • Sleep maintenance insomnia
  • Sleep disorder breathing like sleep apnea
  • Sleepwalking

Causes of nocturnal asthma

The main reason for nocturnal asthma is still unknown. But some studies manifest that many factors collectively contribute to the symptoms of asthma at night.

The factors that contribute to nocturnal asthma are

  1. Increased Mucus Secretions

During sleep, smooth muscles of bronchial tubes contract a bit resulting in narrowing of bronchioles. It causes difficulty in breathing which leads to coughing. Coughing further constricts the airways and facilitates the increased mucus secretions, hence precipitates asthma symptoms. 

  1. Sinusitis

Inflammation of air sinuses is called sinusitis. Air sinuses become inflamed and swollen; produce extra mucus that causes a stuffy nose. At night, postnasal dripping causes the entry of mucus in the airways. That lead to allergic reaction and initiation of asthma symptoms.

  1. Cold Air

At night, especially in winter and in an air-conditioned room, the air becomes cold. When cold air is used in breathing, it causes the cooling of airways. It absorbs the heat and moisture from the bronchioles. Dry and cold airways trigger the hypersensitivity reaction and chest tightness. To prevent this, air humidifiers are used.

  1. Gastroesophageal Reflux Disease (GERD)
It is a digestive tract disorder that affects the ring of muscles between the oesophagus and stomach. The stomach produces acid that returns to the oesophagus during sleep in GERD. That backup acid may enter the throat and larynx and stimulate severe bronchospasm.
 Sometimes, the use of bronchodilators that treat the symptoms of asthma also dilates the oesophageal sphincters. In that case, if the patient is also suffering from acid peptic disease and GERD, a considerable amount of acid enters the larynx and bronchioles. This acid severely damages airways and cause allergic reactions in the respiratory tract.
  1. Hormonal factors

Epinephrine is a very important hormone that controls the sympathetic response of the body and plays a major role to prepare the body in an emergency. It also relaxes the smooth muscles and inhibits the secretion of histamine, thus helps in the normal respiratory processes. But at night, almost at 4:00 am the blood epinephrine level is lowest while histamine level is maximum, making a favourable situation for the attack of asthma.

  1. Late phase reaction

When an asthmatic patient encounters an allergen; there are two types of reactions

    • Immediate reaction
    • Late phase reaction (in half patients)

Immediate reactions occur simultaneously. It is acute with severe asthma but short-term. The symptoms last only for one hour. After the recovery, the second phase of symptoms occurs with a longer duration of action that lasts only for 3-8 hours in half of the patients, called late-phase reaction. If you get an allergic reaction in the evening, then there is a strong chance of the second wave of symptoms at late night.



  • Calhoun, W. J. (2003). Nocturnal asthma. Chest, , 399S-405S.
  • Sutherland, E. R. (2005). Nocturnal asthma. Journal of Allergy and Clinical Immunology, 116(6), 1179-1186.
  • Sutherland, E. R. (2005). Nocturnal asthma. Journal of Allergy and Clinical Immunology , 116(6), 1179-1186.



Asthma, Inflammation, Hypersensitive reactions,Respiratory tract, Nocturnal asthma, Exacerbation , Sleep apnea, Increased Mucus Secretions, Sinusitis, Gastroesophageal Reflux Disease (GERD), Hormonal factors, Late phase reaction

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