Dangers of Breathing Cold Air

Dangers of Breathing Cold Air (Credit: Cold Avenger)

Prolonged exposure to cold air can present a serious threat to the body's vital organs and systems.

The body uses a few different means to protect itself from cold air, the first lines of defense being the nose, mucus system, and lungs.

The nose helps protect the lungs by adding moisture and increasing temperature to inhaled air. When a person is exposed to cold temperatures, the tissue lining the nose swells as the capillaries open. This brings warm blood to the nose to heat the cold air. In fact, often it's too much blood in the nose (not increased mucus) which results in nasal congestion.

The body's next defense against cold air is the mucus lining in the airways. The mucus lining acts as a barrier protecting the airways from dangerous particles and organisms, including bacteria that can cause the common cold and other airway infections. As the mucus lining in the airways is exposed to cold air it thickens through inflammation and dehydration and can block airways. Cold can incite inflammation and airway swelling leading to asthma.

If cold air does reach the lungs despite the body's natural nose and mucus defenses, the lungs may react by releasing histamine and other inflammatory mediators. Histamine is a natural chemical often released by the body during allergic reactions. In people with sensitive airways or asthma this causes wheezing.

On average, a human breathes 1,100 times per hour, with each breath measuring about one liter in volume and requiring humidification to keep the lungs and airway from drying. When inhaled air is cold, the body works to heat the air to 98°F and humidify it to 100%. This extra work represents a significant effort and heat loss to the body.

By passively humidifying and gently warming inhaled air with a ColdAvenger face mask, lungs are protected from the damaging effects of dry/cold air.

Why cold air makes your nose run (Credit CNN)

About 50-90% of people get a runny nose when it's cold. We call this "cold-induced rhinitis", or "skier nose". People with asthma, eczema and hay fever seem to experience it more.

It's the job of your nose to make the air you breathe in warm and wet so that when it gets to your lungs it does not irritate the cells.

When inhaling air through the nose at subfreezing temperatures, the air in the back of the nose is usually about 26°C (78.8˚F), but can be as high as 30°C (86˚F). And the humidity of air at the back of the nose is usually around 100%, irrespective of how cold the air is we're breathing in.

This shows the nose is very effective at making sure the air we breathe becomes warm and wet before it reaches the lungs.

So how does it do this?

Cold, dry air stimulates the nerves inside your nose, which send a message through your nerves to your brain. Your brain then responds to this impulse by increasing the blood flow to the nose, and these dilated blood vessels warm the air passing over them.

Secondly, the nose is triggered to produce more secretions via the mucous glands in order to provide the moisture to humidify the air coming through.

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The cold, dry air also stimulates cells of your immune system (called "mast cells") in your nose. These cells trigger the production of more liquid in your nose to make the air more moist. It's estimated you can lose up to 300-400mL of fluid daily through your nose as it performs this function.

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Heat and water loss are closely related: heating the air in the nasal cavities means the lining of the nasal cavity (mucosa) becomes cooler than core body temperature; at the same time, water evaporates (becomes vapour) to make the air moist.

Water evaporation, which requires large amounts of heat, takes heat from the nose, thus making it cooler.

In response, the blood flow to the nose increases further, as the task of warming the air that's breathed in takes precedence over heat loss from the nose (the body's normal response to cold is to shunt blood away from the surface to the deep vessels to minimise heat loss from the skin).

So it's a difficult balancing act to achieve the correct amount of heat and moisture lost from the nose.

When the compensatory mechanism is a little too overactive, moisture in excess of that needed to humidify this cold, dry air will drip from the nostrils.

Mast cells are usually more sensitive in people with asthma and allergies, and blood vessel changes more reactive in those who are sensitive to environmental irritants and temperature changes. So nasal congestion and even sneezing can be triggered by the cold air.

Treatment is usually simply to carry some tissues or a handkerchief. Although the use of anticholinergic (blocks nerve impulses) and anti-inflammatory nasal sprays such as Atropine and Ipratropium have been trialled with some success.

Cold Weather and Runny Noses (Credit: Very Well Health)

While you may wish you could turn your runny nose off like a faucet, that drip actually serves several important purposes in protecting your health. The moisture protects your mucous membranes, traps germs such as bacteria and viruses, and keeps foreign substances out of your nasal passages and body.

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While your body produces between one and two quarts of mucus every day, certain conditions can increase that amount.1 Allergies caused by pollen or mold in the air, rhinoviruses (also known as the common cold) and irritation can all cause your body to secrete excess mucus, as can exposure to cold weather.

What to Do When You Get a Cold

Vasomotor Rhinitis

When you only have a runny nose while outdoors in cooler temperatures and no other symptoms of allergies or illness, the culprit could be vasomotor rhinitis, a type of nonallergic rhinitis caused by changes in temperature, humidity, and exposure to strong odors and perfumes.2 Usually, a person with vasomotor rhinitis will have production of clear nasal discharge that may drain out of the front of the nose, down the back of the throat, or result in nasal congestion.

Why Temperature Matters

Your body has an inherent intelligence that prompts it to take action to protect itself when needed. When exposed to cold temperatures, the additional mucus warms and moisturizes the air taken in through your nasal passages. This protects your mucous membranes in your nose from damage due to the dry, cold air and also protects the bronchioles (delicate air sacs) in your lungs from damage.

In addition, a runny nose due to cold temperatures is a phenomenon similar to condensation. While the air you breathe in may be cold, your body temperature warms the air and when you exhale, you release that warm, moist air into the environment (which is cold). As these two temperatures meet, droplets of water are produced, ultimately dripping down from your nose along with the mucus they mix with.

How to Prevent Cold-Weather Runny Nose

The only way to effectively prevent a runny nose from developing due to cold exposure is to avoid breathing in cold air. One way to do that is by covering your nose and mouth with a wrap or scarf while outdoors, which allows the air to become warm and moist before you inhale it.

Vasomotor rhinitis will not usually get better with antihistamines but may get better by using a nasal steroid or nasal antihistamine spray. The best medication for the treatment of vasomotor rhinitis, especially when the symptoms are a nose that “runs like a faucet," is Atrovent (ipratropium bromide) nasal spray.2 Atrovent works by drying up the mucus-producing cells in the nose and can be used as needed since the spray will start working within an hour. Atrovent nasal spray is available by prescription only—check with your doctor to see if this medication is right for you.

Finally, use a humidifier while indoors.1 Even if the temperature in your home is mild, air is generally drier during cold-weather months. Humidification can help keep your mucous membranes optimally moistened.