If you have chronic pulmonary obstructive disease (COPD), you might have noticed that your breathing often gets difficult when you go out into cold weather. This is no coincidence. There is evidence that cold weather affects the respiratory system in numerous ways, and people with respiratory illnesses such as COPD and asthma are more likely to be affected.
In this blog post, we will discuss the normal environment of your lungs and upper airways, how cold weather affects your lungs, and how to prepare yourself to prevent weather-induced COPD exacerbations or infections.
The Normal Environment of Your Lungs and Upper Airways
The upper and lower airways have several important functions to protect your lungs:
Filtering out foreign particles
Heating the air you breathe
Humidifying the air you breathe
Protecting the lower airways from infection
These functions occur at varying points starting from your mouth and nose down to the lower airways of your lungs. Under normal conditions, our airways are warm and moist to keep 3 critical processes running smoothly: the cough mechanism, the sneeze mechanism, and the mucociliary escalator.
The upper airways use both the cough and sneeze mechanisms to clear out particles and microorganisms from your mouth, nose, and throat. Collectively known as mucous membranes, when your mouth, nose, and throat are adequately hydrated, your cough and sneeze mechanisms clear out these foreign particles by collecting them in mucus and expelling them outward. Your nasal passages also have strands of hair that act as a collective filter for larger particles, thus preventing foreign particles from being inhaled.
The mucociliary escalator is a physiological function of your lungs that moves foreign particles upwards and out of the lower airways. Your body keeps this process intact when you are adequately hydrated enough to maintain the thin layer of mucus that lines the inside of your lungs (which traps foreign particles) and when the cilia (or small hair-like strands) have adequate warmth to freely push the mucus upwards and out of your lungs to be expelled.
These processes are critical for providing ongoing protection against inhaling foreign and potentially infectious particles. However, when cold weather hits, these processes are in danger of failing.
The Danger of Cold Air for People With COPD
While it might seem harmless to go out in cold weather if you just wear an extra set of clothing, there is established evidence that shows people with COPD are significantly more at risk for exacerbations and infections when exposed to cold weather.
One 6-year study by P. Marno et al. (2006) showed that if cold weather lasted for a week or more, there was a subsequent increase in hospital admissions for COPD patients. A later 10-year study in 2013 confirmed these findings, showing that cold stress increased COPD exacerbation rates. Another study in 2017 found that even cold temperatures indoors (64 degrees Fahrenheit or lower) can adversely affect COPD patients.
The Danger of Cold Air for People With COPD
The obvious question is this: How does cold air affect the lungs of COPD patients to put them more at risk for exacerbations and infections? There are several causes at play here.
First, as cold air gets deeper into the lungs, the coldness adversely affects the mucociliary escalator. As mentioned earlier, the mucociliary escalator needs to be warm and moist to function appropriately. However, when cold air is inhaled long enough to get into the lower airways, this dries out the mucus layers of the lungs and stops the cilia (or hair-like strands) from moving foreign particles out of the lungs. Without this critical process in place, your lungs have lost an important defense mechanism against infection. If foreign particles and microorganisms are allowed to enter the lungs unimpeded, that could turn into an infection. Infection risk further increases if you live near water, since viruses and bacteria can be sprayed into the air, stay airborne, and travel great distances by wind.
Second, breathing in cold air effectively dries out the mucous membranes in the nose, which causes inflammation and nasal blockage. The nose is capable of secreting a lot of mucus to stop foreign particles, but when it is dried out by cold air, the mucus thickens and makes it harder to breathe through your nose.
Finally, cold air can trigger reflex bronchoconstriction, which is the inflammation and constriction of your upper and lower airways in response to the cold air. When this happens, you might feel like you suddenly cannot catch your breath after being in the cold for a few minutes or more.
Now that we have covered the normal environment of your lungs and how dry, cold air can negatively affect your lungs, let us now discuss ways to prepare yourself if you must go out into the cold.
How to Prepare Yourself If You Must Go Out into Cold Weather
Here are 9 steps to take to fully prepare yourself if you must