Nocturnal asthma is a term used to describe the asthma of patients whose symptoms strike mostly at night – often while the patient is sleeping. The majority of these attacks occur between midnight and 8 a.m., peaking on average around 4 a.m. This is when pulmonary (lung) functions are at their lowest level, because circulating blood levels of epinephrine and cortisol – which protect the body against asthma – are at their lowest levels.
Nearly 75 percent of asthma patients experience increased symptoms at night, according to the American Academy of Allergy, Asthma and Immunology. Frequent bouts of nocturnal asthma may indicate that a patient’s asthma is not being properly controlled.
Experts believe several factors may be responsible for the increased incidence of asthma symptoms at night. These include the body’s circadian rhythms, the internal clock that regulates the ebb and flow of various chemicals and body functions.
Patients with nocturnal asthma should consult a physician. This condition is often an indicator of severe asthma or asthma that requires further treatment. Certain behavioral modifications can reduce the likelihood of night–time symptoms. Medications also are available in time-release or long-lasting formulations to ensure that a patient with nocturnal asthma gets the medicine they need when they need it most.
About nocturnal asthma
Nocturnal asthma is a term used to describe the asthma of patients whose symptoms strike mostly at night – often while the patient is sleeping. The majority of these asthma attacks occur between midnight and 8 a.m., peaking on average around 4 a.m. Nearly 75 percent of asthma patients experience increased symptoms at night, according to the American Academy of Allergy, Asthma and Immunology.
People with asthma experience inflammation of the bronchial tubes, even when symptoms are not present. This causes a narrowing of the airways and an increased sensitivity to allergens or other stimuli. Exposure to these triggers often produces symptoms such as coughing, wheezing and an inability to breathe normally (shortness of breath). In rare cases, a severe asthma attack can be fatal.
For reasons not completely understood, asthma symptoms tend to occur far more often at night. One British study found that the majority of asthma–induced hospital deaths and episodes of ventilatory arrest occur at night. Regular nocturnal asthma episodes are often an indicator of a severe asthma condition or one which needs additional treatment. However, experts are unsure whether nocturnal asthma is its own unique condition or just a symptom of severe asthma.
Individuals who experience nocturnal asthma symptoms should report them to their physician. Medication changes can often be made to better treat this type of condition.
The breathing problems associated with nocturnal asthma often cause patients to awaken during the night. Disruptions in the amount or quality of sleep can result in daytime sleepiness, and affect the ability to learn and perform tasks. Therefore, treatment for nocturnal asthma can also improve quality of life.
Signs and symptoms of nocturnal asthma are the same as with other asthmatic conditions, though they are often underreported to physicians because they occur at night.
Potential causes of nocturnal asthma
The factors that contribute to nocturnal asthma remain a bit of a mystery. Experts believe a person’s internal body clock (circadian rhythms) may play a role. Certain body functions ebb and peak at various times over a 24-hour period. For example, lung function peaks in most people at 4 p.m. and is at its lowest point at 4 a.m. This latter time is a period when asthma attacks frequently occur, possibly because the body is more vulnerable to attack at that time.
This circadian cycle – sometimes called diurnal variation – depends on a person’s sleeping and waking cycle. Thus, a person who works at night and sleeps during the day is more likely to suffer from “nocturnal asthma” during daylight hours
Recent studies have also indicated that the hormone melatonin may play a key role in triggering nocturnal asthma attacks. Melatonin is a hormone produced by the pineal gland that helps regulate circadian rhythms such as eating and sleeping. However, recent studies suggest that melatonin also enhances allergic airway inflammation, making asthma attacks more likely. Melatonin is widely available in over-the-counter medications used to treat jet lag and insomnia. Experts suggest asthmatics avoid drugs containing melatonin until further information is available.
Other factors believed to contribute to nocturnal asthma include:
- Allergens. Pollen, pet dander, dust mites, cockroach debris and other household allergens frequently trigger nocturnal asthma. Sometimes, a delay occurs between the exposure to the allergen and the onset of asthma symptoms. Therefore, exposure in the evening hours may cause an asthma attack in the middle of the night. Additionally, allergen exposure, especially to dust mites, is highest in the bedroom.
- Airway inflammation. In some people with asthma, the airways become more inflamed at night as chemical levels change during the body’s natural circadian rhythms.
- Airway secretions. Chronic rhinosinusitis and postnasal drip are both believed to be contributing factors to nocturnal asthma.
- Airway cooling. Cold air is a known asthma trigger. Body temperature can drop rapidly during sleep, which may help to trigger an asthma attack.
- Heartburn (e.g., acid reflux, gastroesophageal reflux disease). For some people, lying down can cause stomach acids to drain into the tube leading from the throat to the stomach called the esophagus. The irritation and coughing that often result can trigger asthma symptoms. In some cases, successfully treating a reflux condition can lead to improvements in nocturnal asthma.
- Decreased strength of asthma medication. Patients who normally take asthma medications early during their daily routine may have lower levels of the medication left in their bodies prior to awakening. A physician can prescribe medications that will be strongest during periods when a nocturnal asthma attack is most likely.
- Sleep apnea. People with this disorder experience sudden momentary breathing cessation. This upper-respiratory disorder may cause reflexes in the lower airways that trigger an asthma attack.
- Obesity. Nocturnal asthma appears more often in patients who are obese.
Diagnosis and treatment of nocturnal asthma
In diagnosing nocturnal asthma, a physician will conduct a physical examination and obtain a full medical history. Particular attention is likely to be focused on when and how frequently symptoms occur. These details can give a physician important insight into how best to treat an individual case of asthma.
If the patient has not previously been diagnosed with asthma, a series of other tests are likely to be performed to confirm the asthma diagnosis.
Once a physician has a clear understanding of the symptoms and when they most often strike, time–release or long–lasting medications (e.g., long acting beta agonists) can be prescribed. Such medications can ensure that a drug’s treatment power is peaking just when the patient is likely to need it most.
Some individuals may successfully treat nocturnal asthma by treating related conditions that are exacerbating the asthma condition. Gastroesophageal reflux disease, allergic rhinitis (hay fever) and sinusitis can cause nocturnal asthma symptoms to worsen. Independently treating these conditions often improves nocturnal asthma symptoms.
Prevention methods nocturnal asthma
It is impossible to completely prevent every bout of nocturnal asthma. But the right medication and treatment plan can drastically reduce the incidence of symptoms. Prevention measures the patient can take to lessen the likelihood of an asthma attack include:
- Make sure the bedroom is as allergen-free as possible. To cut down on dust, remove carpets, use plastic blinds instead of drapes and use allergen-proof covers for mattresses, box springs and pillow. In addition, make sure pets stay out of the bedroom.
- Those who suffer from rhinosinusitis should be sure to treat their condition so the sinuses remain clear. This should help prevent symptoms.
- Use a humidifier to keep the air warm and moist (but not too damp), which will help keep body temperature from falling too low. If necessary, turn up the heat to make sure the room does not get too cool.
- Consult a physician about a treatment plan to help control episodes of sleep apnea. Changes in sleeping position, devices that keep the throat open and medications are all used to treat this disorder.
Questions for your doctor
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions regarding nocturnal asthma:
- Does the timing of my symptoms indicate nocturnal asthma?
- What may be causing my symptoms to strike at night?
- Is my nocturnal asthma an indication that my asthma medication is not working?
- Do I have a medical condition that may be contributing to my nocturnal asthma?
- Will you be performing any tests to determine if I have nocturnal asthma?
- What are my treatment options?
- Would I benefit from changing medications?
- How can I prevent asthma attacks from occurring at night?
- I have read that the hormone melatonin may contribute to nocturnal asthma. Should I avoid melatonin-containing products?