Why is asthma worse at night?

Getting a good night’s sleep is vital to staying healthy, both physically and mentally. But, that can be hard if you’re up all night coughing and wheezing. 

“Nocturnal asthma” is when you experience a flare-up of asthma symptoms overnight. It can lead to a loss of crucial shuteye and exacerbate daytime asthma. Much like daytime asthma, common symptoms of nocturnal asthma include coughing, wheezing, shortness of breath, and chest tightness. However, after a night of triggered symptoms (and lack of sleep), you may experience adverse effects, such as trouble focusing, excessive daytime sleepiness, and additional asthma issues and symptoms.

It’s not fully understood why asthma symptoms worsen at night, but there are ways to prevent nighttime asthma and stop that pesky cough in its tracks. 

Why is my asthma worse at night?

Although asthma can occur at any time of the day, many experience issues with asthma flare-ups at night. Despite the lack of understanding around the condition, experts have identified several potential nocturnal asthma causes. Here, we discuss six things that could be keeping you up coughing all night.

1. Sleeping position

As you fall asleep, your muscles relax, making your airways narrow and increasing resistance in your lungs. On top of that, “lying down can cause more mucus to pool in your airways,” which can trigger coughing for people with asthma, explains Paul Daidone, MD, internist and medical director at True Self Recovery in Rogers, Arkansas. 

2. Allergen exposure

Throughout the day, your exposure to allergens builds up—one potential reason people with asthma start to feel worse as the evening stretches on. Depending on your asthma triggers, you may be having a late-phase allergic reaction, or one that peaks six to nine hours after your initial exposure. Alternatively, your bedroom or sleeping environment may contain allergens that cause asthma attacks at night, such as dust mites, pet dander, or other irritants.

3. Room temperature

Cold air irritates the airways, so sleeping with the air conditioning on or a window open can lead to difficulty breathing. Cold air also tends to be dryer, which can make bronchial tubes constrict even more—a common trigger for people with exercise-induced asthma. 

4. Hormonal changes 

Hormone secretion changes throughout the day with your circadian rhythm. Epinephrine, the hormone that relaxes the muscles in the bronchial tubes, decreases at around 4 a.m. This may lead to the closing of your airways, or bronchospasms, and mucus secretion. “Hormones that are secreted in a circadian pattern that can contribute to nocturnal airway inflammation and asthma include cortisol and melatonin,” says Raj Dasgupta, MD, a pulmonologist and associate professor of clinical medicine at the Keck School of Medicine at the University of Southern California. 

5. Acid reflux

Gastroesophageal reflux disease is a condition where stomach acid enters the esophagus and causes symptoms like a burning feeling in your throat, gas, and chest discomfort. This condition often overlaps with asthma and worsens at night when your body’s horizontal position makes it easier for stomach acid to flow upward. Excess acid can trigger bronchial spasms in people with asthma.

6. Poorly controlled daytime asthma

If your asthma symptoms are not well-managed by medications or lifestyle changes during the day, you’ll likely experience the same or worsening symptoms at night.

Risk factors for nighttime asthma

In addition to these potential causes, several risk factors make someone more likely to experience nocturnal asthma symptoms. They include:

• Obesity and excess weight: Weight gain and obesity, especially around the chest and abdomen, have been linked to asthma development. Although researchers are still trying to understand how this happens, one explanation is that extra weight can cause inflammation and constriction of the airways. 
• Smoking: Smoking weakens lung function and irritates your airways. In fact, research shows the incidence of asthma is higher if a patient’s mother smoked during pregnancy. Avoid smoking and secondhand smoke if at all possible. 
• Exposure to air pollution: Certain air pollutants, especially smog common to larger metropolitan areas, may raise a person’s risk of developing asthma and symptoms in the evening hours after all-day exposure. 
• Allergy history: Allergic rhinitis is significantly associated with asthma development. Allergies can agitate asthma symptoms by causing mucus build-up overnight, which leads to nocturnal asthma issues. 
• Viral infection history: Viral colds, influenza, or COVID-19 can worsen asthma symptoms and put existing asthma patients at risk for uncomfortable nocturnal symptoms. 

How to prevent nocturnal asthma

Although there is no cure for asthma, there are many ways you can prevent attacks overnight—particularly by minimizing the impact of common causes with lifestyle changes and medication. Here are tips that providers recommend.

Reduce allergen exposure in the bedroom: Dust mites, mold, and pet dander are common allergens that can close airways. To reduce them in your bedroom, wash your bedding regularly, control humidity to limit mold growth and too-dry air, avoid feather pillows, use an air purifier with a HEPA filter, and keep pets out of your bedroom. 

Adjust your asthma action plan: When your daytime asthma symptoms are out of control, it will inevitably lead to difficulties with your nighttime asthma symptoms. Talk to your healthcare provider about tracking your symptoms and changing your medication regimen. If you have an inhaler, keep it on your bedside table. 

Treat other health conditions: Managing underlying health conditions—especially GERD, sleep apnea, and allergic rhinitis—can help relieve and prevent asthma symptoms. Although not explicitly linked to asthma, people with both asthma and at least one of those conditions are known to experience additional complications from their asthma symptoms, especially at night. Keep up with any medications and prevention methods prescribed by your healthcare provider if you want to see improvements in your asthma symptoms as well. 

Change your sleeping position: Although some positions will work better for others, sleeping on your back with your neck and shoulders elevated will help prevent nocturnal asthma. “Sleeping in a slightly elevated position can help prevent the pooling of mucus in the airways,” Dr. Daidone says. “This can be achieved by using an extra pillow or wedge pillow.” The right pillow height matters more than you may think for lung function at night. 

Avoid other triggers: Of course, you should also quit habits like smoking if you have asthma. Certain scented products, like candles, cleaning products, or perfumes could also irritate your asthma. If you notice this triggers symptoms, find ways to cut out scented products, especially in your sleeping area.

How to stop an asthma cough at night

In addition to the above prevention options, having an asthma treatment plan will always make stopping a cough easier. Typically, this involves having asthma medication on hand and along with natural remedies:

• Use medication. Your healthcare provider will prescribe asthma medication depending on the severity of your asthma, including preventive medications, such as long-acting beta agonists or corticosteroid inhalers like Pulmicort (budesonide) and Asmanex (mometasone), and quick-relief, rescue medications such as Ventolin (albuterol). 
• Keep a glass of water by your bedside. Slow, small sips of water at the onset of a flare-up can help soothe your airways. 
• Try breathing exercises. Your healthcare provider may teach you breathing techniques to get through episodes of uncomfortable asthma coughing. Sit upright while doing them as lying down flat or on your side will make breathing even harder. 

If your asthma cough worsens over the night despite all of these prevention techniques, contact your healthcare provider. There are ways to manage your nocturnal asthma symptoms to get better sleep for a better quality of life.