#745 Does being cold or wet increase your chance of catching a cold?

Does being cold or wet increase your chance of catching a cold? Being wet doesn’t make much of a difference, but being exposed to cold air can increase your chances of catching a cold. And, if you are cold for a long period of time, it can lower your immunity.

The common cold is caused by a virus and there are over 200 different strains that cause a cold. The most common is the rhinovirus, which causes about 40% of all colds. The viruses enter our bodies and corrupt the DNA in our cells to reproduce themselves. Then they spread to other hosts when we cough or sneeze, or in our saliva. They can live for several hours outside the body, so long as they don’t dry out. Many people think that being cold or wet can increase your chance of catching a cold. This is probably because more people catch colds and flus in the winter. So, why is that?

Cold and flu viruses are present all year round, but there are several reasons why colds peak in the winter. The first reason is that we spend more time inside with the windows closed. If there are more people gathered together and there is no incoming fresh air, it is much easier for viruses to spread. The second reason is that the humidity in the summer can provide a shield. Just like resistance in metal, in humid conditions there are more water drops in the air that can trap the viruses. That being said, there are some viruses that prefer warm conditions to cold.

The third reason is the main reason why we have an increased chance of picking up a cold in cold weather. A large number of viruses enter the body through the nose. Our noses produce membrane-bound particles called extracellular vesicles. A vesicle is like a bubble that can trap and transport things. These extracellular vesicles can trap viruses and bacteria, stopping them from entering the body. The lining of the nose is able to detect when a virus or a bacteria has attached there and it can increase the production of extracellular vesicles by 160%. Studies showed that the front of the nose will react before the back of the nose, stopping the virus as soon as it enters the nose. The extracellular vesicles then get passed out of the nose with other mucus, protecting the body. When the air is cold, it hinders the production of extracellular vesicles and a drop of 5 degrees Celsius can reduce them by more than 40%. Fewer extracellular vesicles means more viruses will be able to get into the body. So, being cold can increase your chances of catching a cold because it reduces the production of extracellular vesicles.

The cold also plays a part in how quickly a cold is fought off. Prolonged exposure to the cold doesn’t increase your risk of getting a cold any more than short term exposure does, but it does reduce your ability to fight the cold off. Prolonged exposure to the cold suppresses the immune system. When you get a cold, your body detects it and releases chemical signals to attract white blood cells to come and attack the virus. It also raises the body’s temperature because viruses can’t survive in very hot conditions. Prolonged exposure to cold slows down the immune system and it doesn’t react as easily or as quickly to attacks. Its response is much less effective and very cold people can’t fight off colds.

High stress, sleep deprivation, and exhaustion can all weaken the immune system as well. When we are stressed, the body produces cortisol, which boosts the immune system. However, if the stress continues, it can cut the amount of white blood cells the body is able to produce. White blood cells fight off colds, so fewer of these means it’s harder to fight off a cold. Sleep deprivation has the same effect. Lack of sleep alters the structure of the DNA inside the immune system stem cells that produce white blood cells, making them less effective. Exhaustion has the same result as well. If we live in a constant state of “flight or fight” our body stops prioritizing the immune system and we become unable to fight off colds.

So, being cold can increase the likelihood that you might catch a cold, but cold itself doesn’t increase the amount of cold viruses that are in the air. And this is what I learned today.

Photo by Andrea Piacquadio: https://www.pexels.com/photo/woman-lying-on-bed-while-blowing-her-nose-3807629/

Sources

https://cornerstonenaturopathic.ca/how-burnout-affects-your-immune-system/

https://www.mountsinai.org/about/newsroom/2022/a-consistent-lack-of-sleep-negatively-impacts-immune-stem-cells-increasing-risk-of-inflammatory-disorders-and-heart-disease

https://vicks.com.au/en-au/science-of-healing/understanding-types-of-illness/how-your-body-fights-off-cold-and-flu

https://ccforum.biomedcentral.com/articles/10.1186/cc10080

https://www.uclahealth.org/news/new-study-links-nose-temperature-and-immune-response

https://www.medicalnewstoday.com/articles/vesicle#structure

https://www.cnn.com/2022/12/06/health/why-winter-colds-flu-wellness/index.html

https://www.medicalnewstoday.com/articles/why-do-we-always-seem-to-catch-a-cold-or-flu-in-cold-weather-a-new-study-explains#The-nose:-A-gateway-for-viruses?

https://www.mayoclinic.org/diseases-conditions/flu/expert-answers/infectious-disease/faq-20057907

https://www.horizonhealthnews.com/why-do-viruses-spread-more-in-winter-cold-temps-are-key/