Understanding causes of nocturnal asthma (nighttime asthma)

Asthma, a respiratory condition that makes it difficult to breathe, is common: about one in every 13 people in the U.S. has it. Asthma affects people of all ages, but it often starts during childhood.

Nocturnal asthma is simply a term for asthma symptoms that are worse at night. In this article, learn about triggers and risk factors for nocturnal asthma, its impact on quality of life and some treatment strategies to help prepare for a discussion with a health care provider. 

In this article:

What is nocturnal asthma?

Asthma is a chronic (long-term or lifelong) condition that causes airways to narrow or become inflamed, causing symptoms like coughing, wheezing, shortness of breath or chest tightness.

Nocturnal asthma or nighttime asthma is simply an exacerbation of asthma at night — worse symptoms, lower lung function and an increased need for medication during the nighttime hours.

Symptoms of nocturnal asthma

The symptoms of nighttime asthma are very similar to the symptoms of asthma, but they typically tend to be worse or happen only at night. Symptoms include:

• Chest tightness
• Coughing
• Shortness of breath
• Wheezing

Children might also exhibit daytime sleepiness, disturbed sleeping and trouble focusing in school.

Diagnosing nocturnal asthma

Those wondering if they have nocturnal asthma should make an appointment with a health care provider. They will likely need to use differential diagnosis, ruling out additional conditions that match symptoms to ensure they are making an accurate diagnosis. Asthma differential diagnoses include the following:

• Congestive heart failure 
• Dust mite and mold allergies 
• Foreign bodies
• GI reflux
• Obstructive sleep apnea
• Sinus disease
• Tracheal and bronchial lesions
• Vocal cord dysfunction

In a clinic setting, a health care provider will measure lung function using a spirometry or pulmonary function test (PFT). At home, a person may use a device called a peak expiratory flow (PEF) meter to measure their lung function throughout the day. These measurements can help a health care provider determine whether a person has nocturnal asthma.

Pathophysiology of nocturnal asthma

Why do asthma symptoms tend to get worse at night or while asleep? Just like the rest of the body, lung function has a circadian rhythm. Generally, the best lung function happens at 4:00 PM and the worst lung function at 4:00 AM. People with asthma experience an even more exaggerated swing in this chronobiology (i.e. time-related rhythm).

Another factor affecting nighttime asthma is hormones. The circadian pattern in which hormones are secreted can make airway inflammation more likely. Melatonin, for example, has a proinflammatory effect in people with nocturnal asthma, with high melatonin levels causing a greater overnight fall in lung function.

The activity of the vagus nerve, which is part of the nervous system, may also affect breathing. At night, vagal tone increases, which may be an additional contributor to nocturnal shifts in airway function. And shallow, slow breathing during sleep can also cause reduced lung volumes, meaning lower lung capacity.

Triggers and risk factors

Certain things can trigger nocturnal asthma symptoms or cause nighttime asthma to be worse.

Allergens and airborne irritants

Exposure to allergens at night, such as dust mites, mold or pet dander (similar to some of the allergens that cause seasonal allergies) can trigger nocturnal asthma.

Psychological stress

Stress and anxiety may trigger nocturnal asthma symptoms because feeling strong emotions (like anger, excitement or fear) makes breathing change. This in turn, causes muscles to tighten or breathing to quicken. Asthma symptoms may also worsen during pregnancy due to hormonal symptoms.

Medications and comorbid conditions

Other medical conditions, such as acid reflux, allergic rhinitis, sinusitis or sleep apnea, have been linked with asthma. Asthma symptoms may be more severe if someone has other conditions, too. And medications such as beta-blockers and aspirin are known to be asthma triggers.

Impact on quality of life

Experiencing nocturnal asthma can have a significant impact on quality of life. Studies on children with nocturnal asthma symptoms have shown that these symptoms cause sleep disturbances, leading to negative outcomes in daytime functioning, like poorer school attendance and performance.

Even parents of asthmatic children are affected, experiencing their own sleep disruptions as well as feelings of stress, depression and anxiety.

Treatment strategies for nighttime asthma

A health care provider might prescribe quick-relief medications (like albuterol), controller medications or a combination of the two. In some cases of persistent asthma, biologics are also recommended. The medications may be inhalers, injections or tablets.

“There are four major classes of inhaler medications for the treatment of nocturnal asthma,” explains board-certified allergist and immunologist Sairaman Nagarajan, MD, MPH.

“Typically, the first line of therapy includes a combination of albuterol, a short acting beta agonist (SABA), with an inhaled steroid, such as budesonide or fluticasone, before going to bed. If that doesn’t work, a long-acting beta agonist (LABA) is used, such as formoterol or vilanterol. 

For very severe cases, a long-acting muscarinic antagonist (LAMA) is used, such as ipratropium.”

Managing nocturnal asthma at home

Long-term management plans for asthma treatment often involve lifestyle changes that help avoid asthma triggers as much as possible.

Creating an asthma-friendly sleep environment

To reduce allergens, keep the bedroom clean and wash the sheets regularly. At night, close the windows and keep a consistent, comfortable air temperature with humidity around 50 to 60 percent. An air purifier can help improve air quality.

Following a consistent sleep schedule

Following a regular sleep schedule can help improve nocturnal asthma symptoms and control daytime sleepiness. People may also find it helpful to focus on good sleep hygiene, too, using practices like reading or taking a warm bath to help de-stress before bed.

Eating a healthy diet

Fruits and vegetables in particular have been linked with better asthma control. Dairy consumption is associated with an increased risk of asthma and for exacerbating asthmatic symptoms.

Exercising (carefully)

Physical activity is helpful for asthma because it reduces stress, improves lung function and controls weight. However, since exercise can also be an asthma trigger, it's important for anyone with asthma to consult a health care provider about the recommended type, frequency and duration of exercise that may be best for them.

Managing nocturnal asthma long-term

By making lifestyle changes, consistently complying with any prescribed medical treatment and tracking symptoms people with asthma can take an active role in their care for nocturnal asthma. 

Frequently asked questions 

What is nocturnal asthma?

Nocturnal asthma refers to the worsening of asthma symptoms at night, typically leading to coughing, wheezing and shortness of breath that disrupt sleep.

How does someone know if they have nocturnal asthma?

If a person experiences frequent nighttime coughing, wheezing or shortness of breath, they should make an appointment with a health care provider. They can diagnose nocturnal asthma by evaluating symptoms, conducting lung function tests and monitoring nighttime symptoms.

What can trigger asthma at night?

Common triggers of nocturnal asthma include allergens like dust mites, mold and pet dander, as well as cold air or lying down flat. Hormonal changes and circadian rhythms also play a role.

Can asthma get worse at night?

Yes, asthma often worsens at night. One reason is due to the body’s natural circadian rhythms, which cause airway inflammation to increase and lung function to decrease during sleep.

This content is for informational purposes only and is not medical advice. Consult your health care provider before taking any vitamins or supplements and prior to beginning or changing any health care practices.