The flu, a viral respiratory disease that is often accompanied by chills, a fever, coughing, sneezing and congestion, is more common in winter months for a reason. While the flu is often confused with a common cold, it has a few qualities that make it different:
- The flu and a cold are caused by different viruses. The Centers for Disease Control (CDC) describes four different influenza viruses, types A, B, C, and D. Influenza A is the most common type and what typically causes widespread flu.
- The flu and a cold last a different length of time, and usually a cold is not as severe as a flu.
No virus or bacteria can infect your body unless it gets past your immune system. Your immune system is an incredibly robust bug-fighting machine that uses several soldier-like cells to defeat viruses before they can negatively impact you. In this article we'll explore the link between your immune system and cold weather and explore some tips on how to strengthen immunity this winter.
How Your Immune System Works
There are a few important components involved in your immune system:
- White blood cells called leukocytes are capable of moving around your body, finding infections or foreign substances, ingesting them, destroying them and then creating antibodies.
- White blood cells called phagocytes include neutrophils that most commonly fight bacterial infections and attack invading organisms.
- White blood cells called B lymphocytes and T lymphocytes are located in your bone marrow and thymus gland. They are considered the militia of your body. They look for invading organisms and send a defense team of cells designed to destroy them. Lymphocytes make antibodies (or immunoglobulins) that are created and stay in your body so that the next time a similar invader is present it can easily locate it and destroy it. Antibodies are like a shortcut for eliminating disease. You can see them at work in people who get chicken pox once and then never again.
When your body notices a flu bug, also called an antigen, the immune system kicks in with all these incredible cells to identify it, surround it, and attack the invading bacteria or virus.
Why Flu Symptoms Get Worse in Cold Weather
Does being cold lower your immune system? Is this what causes a flu outbreak in your town every winter?
First, influenza and similar viruses tend to thrive in colder weather. What's more, flu can be a co-morbidity factor in many deaths that happen in the winter. Harvard research points out that 70% of the death rate can be traced back to heart attacks, strokes, and other cardiovascular causes in the winter, and if someone is already suffering from the flu, this makes them more susceptible to negative health outcomes. Your winter immune system has to work harder than it does in the summer months because the flu and similar viruses thrive during colder months.
There are several more reasons why cold weather lowers immune system functions:
- Reduced levels of Vitamin D
- Your blood vessels narrow
- Winter temperatures weaken the nose's immunity
- Dry air affects immunity
Reduced Levels of Vitamin D
Vitamin D is important for immune function. During winter months when we don't get enough sun exposure, our intake goes down because the only way to produce this vitamin in our bodies is through food or supplements. Here's why Vitamin D is so critical for your immune system:
- Vitamin D works with your immune cells (B cells, T cells, and antigen-presenting cells).
- It modulates and adapts your immune response to help handle whatever kind of antigen or bug is present, including different strains of a flu virus.
- Vitamin D is associated with increased autoimmunity. Autoimmunity is your body's ability to automatically identify, attack and destroy harmful viruses and bacteria.
Your Blood Vessels Narrow
Breathing in cold, dry air from winter causes the blood vessels in your upper respiratory tract to narrow. White blood cells that travel through these blood vessels may be blocked from reaching the mucous membrane, preventing our body from fighting off germs.
Research also suggests that certain viruses may be transmitted more easily in the nostrils during colder months, for instance, by inhaling after someone with the flu sneezes or coughs nearby.
Winter Temperatures Weaken The Nose's Immunity
While this research in this area concerns rhinovirus and not specifically influenza strains, it found that for reasons unknown to scientists, viral strains replicate better in cooler temperatures, and these are found more often in the nasal cavities in the winter months, as opposed to the lungs, which are more insulated in the body, and tend to have a slightly warmer temperature.
As Dr. Carl Zimmer explained to the New York Times, "At body temperature, the cells respond with a sophisticated defense, sending out warning signals to uninfected cells around them. Those cells prepared an arsenal of antiviral proteins, which they used to destroy the rhinoviruses. But at a relatively cool 91.4 degrees Fahrenheit, Dr. Iwasaki and her colleagues found things changed. The neighboring cells only managed a weak defense, allowing the rhinoviruses to invade them and multiply. This result pointed to an explanation for why rhinoviruses plague humans at low temperatures: In cool conditions, the immune system somehow falters."
Moreover, your nose is lined with cilia, or tiny hairs that help to catch tiny, microscopic virtual and bacterial organisms as well as dust, and other potential invaders, before they can gain entry into your lungs. When mucus coats these hairs, they can't do their job as well, which is one of the front lines of defense for your immune system.
When you are already infected, however, nasal mucus is your body's friend. It's made of water, proteins, antibodies, and salt and becomes yellow or green when your body is fighting an infection. Your nose runs when the body produces more mucus to flush invaders out. The immune system essentially turns your nose into a faucet in order to keep you healthy and flush out disease. But, the immune response of your nose is suppressed by cold weather.
Dry Air in Colder Months Affects Immunity
Not only does cold weather lower immune system response levels, but dry air does too. Dry winter air makes it challenging for your body to fight off infection. Dryer air lacking humidity allows the flu virus to spread more easily, and since we're also heating our homes to stay warm in the winter, this dries the air even more.
The National Institutes of Health (NIH) even suggests that this dry air may be what spurs a flu outbreak because fewer water molecules are available to interfere with a virus' projection through the air when someone coughs or sneezes.
Boost Natural Immunity During the Winter Months
You can help to reduce your chances of getting the flu this winter with a few changes:
- Use good ventilation coupled with an air humidifier. One study found that influenza A did not spread as easily if humidity and ventilation were used in a room. You can purchase an inexpensive humidifier online. Open windows when the weather is slightly warmer, as outdoor air can be cleaner than indoor air. For an extra immune boost, some humidifiers double as diffusers, so you can add a few drops of orange oil, sage, eucalyptus, or clove oil to help naturally boost immunity too.
- Expose yourself to as much natural sunlight as possible. This may be difficult to do in the winter, but if the weather is mild, soak up the sun and expose as much skin as you can. Skiing, walking, or even sitting in the sun are all great ways to soak up the rays in the winter.
- Get 8 to 10 hours of sleep at night. When you sleep, your body does a major clean up and many of the immune cells do their best work. It is vitally important that you get plenty of rest when you feel a cold or flu coming on to prevent getting sick.
- Protect your immune system in cold weather with the Healthycell Immune Super Boost gel dietary supplement that contains the following immune-boosting compounds:
- Elderberry Extract - One of the most powerful antioxidants in elderberries is quercetin, which can be a powerful antiviral.
- Aronia Berry Extract - Also called chokeberries, these berries are highly antioxidant, reducing free radicals in your body and also have antiviral compounds.
- Echinacea Extract - This plant extract is immunity boosting, and anti-inflammatory. It may help the natural immune response.
- Dark cherry flavonoids - The flavonoids and polyphenols in dark cherries are immune-boosting. They are also rich in Vitamin C.
- Beta-Glucan - Shown in studies to enhance Natural Killer (NK) cell functions and increase your immune response.
- Citrus Pectin - Shown in studies to increases MCP activated B-cells and activates T-cytotoxic cells and Natural Killer (NK) cells in your immune system.
- Vitamin C - The biggest immune-boosting vitamin of all, supporting multiple functions within the system.
- Vitamin D - Supports immune cells that create antibodies.
- Vitamin E - Supports immunity through antioxidant action.
- Vitamin B6 - Helps your body create T cells that boost immune function.
- Zinc - Supports overall immune functioning and may slow viral replication.
Healthycell Immune Super Boost is similar to a liquid vitamin for adults, but it's actually a patent-pending gel. It helps support your body's ability to increase white blood cell quantity and activity† and as you learned earlier, these cells are vital to your overall immune response. As we've learned, being cold affects your immune system, but you don't have to suffer from compromised immunity this year. Make the simple lifestyle changes recommended in this article and supplement the vitamins and minerals your body needs to help protect against the common cold or flu.
You May Also Like:
- Types of influenza viruses. (2020, February 24). Centers for Disease Control and Prevention. https://www.cdc.gov/flu/about/viruses/types.htm
- Leukocytes. (n.d.). Physiopedia. https://www.physio-pedia.com/Leukocytes
- Components of the immune system. (2014). Primer to the Immune Response, 21-54. https://doi.org/10.1016/b978-0-12-385245-8.00002-9
- Ikäheimo, T., Jaakkola, K., Jokelainen, J., Saukkoriipi, A., Roivainen, M., Juvonen, R., Vainio, O., & Jaakkola, J. (2016). A decrease in temperature and humidity precedes human rhinovirus infections in a cold climate. Viruses, 8(9), 244. https://doi.org/10.3390/v8090244
- Out in the cold - Harvard health publications - Harvard health. (2010, January 1). Harvard Health. https://www.health.harvard.edu/staying-healthy/out-in-the-cold
- Singh Chauhan, V. (2021). Vitamin D and the immune system. Vitamin D. https://doi.org/10.5772/intechopen.97300
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- Eske, J. (n.d.). Does cold weather make you sick: What's the link? Medical and health information. https://www.medicalnewstoday.com/articles/323431#cold-weather-and-viruses
- Foxman, E. F., Storer, J. A., Fitzgerald, M. E., Wasik, B. R., Hou, L., Zhao, H., Turner, P. E., Pyle, A. M., & Iwasaki, A. (2015). Temperature-dependent innate defense against the common cold virus limits viral replication at warm temperature in mouse airway cells. Proceedings of the National Academy of Sciences, 112(3), 827-832. https://doi.org/10.1073/pnas.1411030112
- Becker, R. (2015, January 12). Scientists finally prove why cold weather makes you sick. PBS: Public Broadcasting Service. https://www.pbs.org/wgbh/nova/article/scientists-finally-prove-cold-weather-makes-sick/
- Unraveling the key to a cold virus's effectiveness (Published 2015). (2015, January 8). The New York Times - Breaking News, US News, World News and Videos. https://www.nytimes.com/2015/01/13/health/unraveling-the-key-to-a-cold-viruss-effectiveness.html?_r=0
- Does cold weather weaken your immune system? (2021, March 11). Stellar Biotics. https://delimmune.com/blogs/blog/does-cold-weather-weaken-your-immune-system-1
- Dry air may spur flu outbreaks. (2015, July 7). National Institutes of Health (NIH). https://www.nih.gov/news-events/nih-research-matters/dry-air-may-spur-flu-outbreaks
- Yang, W., & Marr, L. C. (2011). Dynamics of airborne influenza A viruses indoors and dependence on humidity. PLoS ONE, 6(6), e21481. https://doi.org/10.1371/journal.pone.0021481
- Sleep & immunity: Can a lack of sleep make you sick? (2020, December 10). Sleep Foundation. https://www.sleepfoundation.org/physical-health/how-sleep-affects-immunity
- Agrawal, P. K., Agrawal, C., & Blunden, G. (2020). Quercetin: Antiviral significance and possible COVID-19 integrative considerations. Natural Product Communications, 15(12), 1934578X2097629. https://doi.org/10.1177/1934578x20976293
- O'BrienDip, S. (n.d.). Aronia berries (Chokeberries): Nutrition, benefits, and more. Healthline. https://www.healthline.com/nutrition/aronia-berries
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- Kelley, D., Adkins, Y., & Laugero, K. (2018). A review of the health benefits of cherries. Nutrients, 10(3), 368. https://doi.org/10.3390/nu10030368
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- Better Health Publishing. (2011, August 16). New study shows modified citrus pectin activates powerful immune responses. PR Newswire: press release distribution, targeting, monitoring and marketing. https://www.prnewswire.com/news-releases/new-study-shows-modified-citrus-pectin-activates-powerful-immune-responses-127817263.html
- 3 vitamins that are best for boosting your immunity. (2021, August 12). Cleveland Clinic. https://health.clevelandclinic.org/3-vitamins-best-boosting-immunity/
†This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.