Why Asthma Is Worse at Night - Op-ed

Asthma is a common disease affecting between 1 and 18% of the world’s population in different countries. Unfortunately, approximately 30 to 70% of people with asthma experience nocturnal asthma, or a worsening of asthma symptoms at night, Dr. Magdy Badran says.

Asthma is one of the major non-communicable diseases. It is a chronic disease of the air passages of the lungs which inflames and narrows them.

Most asthma-related deaths occur in low- and lower-middle-income countries. Appropriate management of asthma can enable people to enjoy a good quality of life.

Nocturnal Asthma

Asthma is a long-term, chronic respiratory disease, caused by the inflammation of the airways. When this condition worsens overnight, we call it nocturnal asthma or nighttime asthma.

Regardless of the type of asthma, you have, including allergic, non-allergic, occupational, and exercise-induced asthma, nocturnal asthma can occur more than once a month.

The factors that contribute to nocturnal asthma include environmental allergens, cold air, hormonal factors, stress, GERD (Gastroesophageal Reflux Disease), the supine sleeping position, obstructive sleep apnea, sinusitis, obesity, and increased mucus production.

The symptoms of nocturnal asthma and regular asthma are the same, but a few may get worse at night, which include: shortness of breath, wheezing, chest tightness, and coughing.

Also, people and especially children may develop other sleep issues, including excessive daytime sleepiness, sleep-maintenance insomnia, sleep-disordered breathing like sleep apnea, and parasomnias like sleepwalking.

Exposure to Allergens

Exposure to allergens is one of the most common reasons asthma is worse at night. Bedbugs, pet dander, and dust mites are common in the bedroom, and all can trigger asthma attacks.

You probably spend 6 to 9 hours in bed every day; that’s a long time to be exposed to potential allergens. Some people also experience delayed allergic reactions at night.

It’s not uncommon for an allergic response to occur 3 to 8 hours after exposure to an allergen. If you’re exposed to pollen, for instance, in the early evening, you might experience shortness of breath and wheezing when you’re trying to fall asleep.

Dust mites may be the most common trigger of year-round allergies and asthma. They are on every continent except Antarctica. They are too small to see with your eyes alone. Under a microscope, they look like white bugs.

They have eight legs, so they are not insects, but arthropods, like spiders. Dust mites thrive in temperatures of 20 to 25 degrees Celsius.

They also like humidity levels of 70 to 80%. There are at least 13 species of mites. They feed mainly on the tiny flakes of human skin that people shed each day.

These flakes work their way deep into the inner layers of furniture, carpets, bedding, and even stuffed toys. An average adult person may shed up to 1.5 grams of skin in a day. This is enough to feed one million dust mites.

Supine Position

The supine position impairs ventilatory function in patients with ongoing asthma. The response is dual: an immediate decrease in lying down, present in healthy persons as well, and a progressive decrease specific for asthmatics.

The changes are counteracted by bronchodilators but are not linked to a decreased plasma adrenaline level when supine. The progressive decrease is tentatively explained by an increased vagal tone induced by the resting body position and is likely to be a key factor in nocturnal asthma.

Acid Reflux

When we lie down, it’s easier for stomach acid to travel back up into the esophagus. Instead of being swallowed, some of this fluid can enter the large airways and provoke an irritating cough. Reflux of stomach acid can also cause the airways to constrict, which leads to more difficulty breathing.

Asthma and acid reflux often occur together. Acid reflux can worsen asthma and asthma can worsen acid reflux — especially severe acid reflux. Asthma and acid reflux can occur together in children as well as in adults. About half the children with asthma also have GERD.

Avoiding reflux triggers, such as fatty foods, alcohol, and tobacco, also may help. If that's not enough, prescription medications may be needed.

Treating acid reflux may help ease symptoms. In some cases, asthma medications can worsen acid reflux. This is particularly true of theophylline.

Postnasal Drip

Post-nasal drip is a condition that occurs when your nose produces too much mucus. When this excess mucus comes out of the front of your nose, a simple runny nose occurs.

Post-nasal drip happens when the excess mucus your nose and other glands produce runs from your nose down the back of your throat.

This process occurs naturally, but when you are producing more mucus than usual or your mucus is exceptionally thick, you can experience the uncomfortable sensation of post-nasal drip.

Sometimes, postnasal drip syndrome is associated with asthma, as the thick mucus secretions drain from the back of the nose to the back of the throat, causing throat clearing, cough, and bronchial constriction. People are more susceptible to postnasal drip at night.

When you lie flat, it’s easier for fluid to drip down the back of your throat and cause coughing.

Lying down also causes fluid to shift from the legs to the chest, which can lead to increased fluid accumulation in the airway walls and narrowing of the breathing passages.

Asthma and Circadian Rhythm

Over the past 15 years, our understanding of the body clock and biological rhythms has increased immeasurably. In 2017, the Nobel Prize in Physiology was awarded jointly to Jeffrey C. Hall, Michael Rosbash, and Michael W. Young for their discoveries of molecular mechanisms controlling the circadian rhythm.

The circadian clock is crucial in regulating daily physiological processes and it is now realized that the time at which our immune system is triggered by infection, vaccination, surgery, appears to be critical to the way we respond to these insults.

Asthma is a disease with a strong circadian rhythm; it is characteristic of asthma that symptoms worsen in the early hours of the morning around 4:00 am.

Nocturnal symptoms in asthma are common and are an important indicator of the escalation of treatment. Sudden death in asthma also tends to occur overnight.

Physiological parameters of airway resistance vary in a circadian manner in healthy inpiduals with a nadir at approximately 4:00 am. However, in asthma, the airway resistance is greatly magnified.

There is a circadian variation in the airway inflammation, the number of alveolar eosinophils (significantly more present at 4:00 am versus 4:00 pm) in subjects with nocturnal asthma compared to those with nonnocturnal asthma. Nocturnal asthma probably represents a group of patients with poorly controlled asthma.

Asthma varies over 24 h. Airways become more narrowed at 4 am in asthma, coincident with increased symptoms and increased airway inflammation also at this time.

Medication Timing

Chronotherapy is the synchronizing of drug concentrations to rhythms in disease activity, increasing efficacy as well as reducing adverse effects.

Improved therapeutic benefit in asthma may be gained by understanding the molecular pathways that drive the predictable, diurnal worsening of symptoms. Timing the delivery of therapy to coincide with pathway sensitivity may deliver maximum benefit. If your asthma medication wears off during the night, you’re likely to experience nocturnal asthma.

Breathing in Cold Air

When the temperature drops by night, asthma symptoms may get worse. Cooler air can dry out the tissues in the airways, making them more sensitive and likely to close up.

A cool room is better for sleep but night-time asthma might be worse in winter or if you sleep in an air-conditioned room. This is because cold air is dry – loss of moisture and heat in the airways can trigger an asthma attack.

Dry and/or cold air is a trigger for airway narrowing (bronchoconstriction). Cold air can especially affect you if you have exercise-induced asthma.

When you exercise, you breathe faster and deeper because your body needs more oxygen. You usually inhale through your mouth, causing the air to be dryer and cooler than when you breathe through your nose.

Stress

Stress can be a major contributor to asthma and anxiety. At the same time, the wheezing and difficult breathing during an asthma attack can cause anxiety.

69% of people with asthma say that stress is a trigger for them. Hormones released by the body in times of stress can cause inflammation so stress may lead to narrowed airways, at least in some people.

Tips to Prevent Nighttime Asthma Attacks

Clean your bedroom regularly. Use a vacuum with a high-efficiency particulate air filter to trap mites and their waste and get them out of your bedroom. Washing bedding in hot water weekly will kill dust mites. Finish the job in a hot dryer.

Don’t sleep with pets. If you have pets, keep them out of the bedroom so their dander doesn’t collect or stick to the carpeting and bedding. You may also need to keep the door to your bedroom shut to keep your pet — and its dander — out.

Keep your head up. If you have a cold or a sinus infection, lying flat can exacerbate postnasal drip. Also, if you have acid reflux, lying flat can allow more acid to creep up into your throat. When you sleep, keep your head slightly elevated.

Get tested for sleep apnea. People with asthma may be at increased risk for sleep apnea. Sleep apnea causes repeated breaks in your breathing while you sleep. It can also worsen asthma symptoms.