Why the sudden chill could leave you sick and how to fight back

Brrr! As temperatures drop, so does our resistance to illness.

The connection between cold weather and increased vulnerability to sickness is not just a myth [1]. It’s a well-documented phenomenon and understanding why this happens can help you take steps to protect your health during colder months.

When winter sets in, the risk of getting sick rises. Here’s how the cold can leave you vulnerable and some strategies to bolster your defenses [2]:

Weakened immune system

Cold weather can weaken your immune system [3]. Our bodies function optimally within a narrow temperature range and exposure to cold can stress the immune system. As a result, it may become less effective in fighting off infections.

Indoor crowding

In colder weather, people spend more time indoors near one another. This can promote the spread of viruses like the flu or the common cold [4]. The more crowded the indoor space, the easier it is for germs to pass from person to person.

Dry air

Cold air is often dry and indoor heating systems can further reduce humidity. Dry air can dry out your nasal passages and make it easier for viruses to enter your body [5]. It also hampers the body’s natural defense mechanisms, such as trapping and expelling viruses.

Reduced vitamin D

In the winter, we tend to get less sun exposure, which means our bodies produce less vitamin D. This essential vitamin plays a vital role in the immune system [6]. Lower levels of vitamin D can make you more susceptible to infections.

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Less physical activity

The cold weather can discourage physical activity. Exercise is crucial for maintaining a strong immune system [7]. When you’re less active, your overall health can suffer, making you more susceptible to illness.

So, how can you fight back against the cold’s impact on your health [8]?

Dress warmly

Wear layers to trap heat close to your body and invest in a good winter coat, gloves and a hat. Keep your extremities warm, as they are more susceptible to cold-related illnesses.

Stay active

Don’t let the cold weather deter you from physical activity. Find indoor exercises or activities that you enjoy. Regular exercise helps boost your immune system.


Combat the drying effects of cold air by staying well-hydrated. Drink plenty of water to keep your mucous membranes moist and better able to trap viruses.

Eat nutrient-rich foods

Consume a balanced diet rich in fruits and vegetables. These foods provide essential vitamins and minerals that support your immune system. Consider taking vitamin D supplements if you need more sun exposure.

Hand hygiene

Frequent handwashing is essential, especially during the cold season. Use soap and warm water for at least 20 seconds to remove germs from your hands.

Avoid crowded places

Limit your time in crowded indoor spaces. The more people you’re in contact with, the higher the risk of exposure to viruses.


Get your flu shot. Influenza is a common winter illness and vaccination can significantly reduce your risk of infection.

In summary, cold weather can leave you more vulnerable to illness due to its impact on the immune system, indoor crowding, dry air, reduced vitamin D and decreased physical activity.

To stay well during the colder months, it’s important to dress warmly, stay active, hydrate, eat a nutritious diet, practice good hand hygiene, avoid crowded places when possible and consider getting vaccinated against the flu. These measures can help you fend off sickness and enjoy a healthier winter season.

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[1] https://www.heart.org/en/news/2021/12/17/can-the-cold-really-make-you-sick
[2] https://www.independent.co.uk/life-style/health-and-families/weather-met-office-superdrug-nhs-b2431142.html
[3] https://www.health.harvard.edu/staying-healthy/out-in-the-cold
[4] https://newsinhealth.nih.gov/2022/01/it-flu-covid-19-allergies-or-cold
[5] https://www.achooallergy.com/blog/learning/the-effects-of-humidity-on-the-human-body/
[6] https://www.hsph.harvard.edu/nutritionsource/vitamin-d/
[7] http://www.gssiweb.org/sports-science-exchange/article/sse-151-effects-of-exercise-on-immune-function
[8] https://oneyoucamden.org/topic/seasonal-health/

The information included in this article is for informational purposes only. The purpose of this webpage is to promote broad consumer understanding and knowledge of various health topics. It is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.