Why You Get Sick in the Winter — and the Simple Habits That Can Stop It

Winter may be known as “cold and flu season,” but getting sick isn’t a foregone conclusion. With thoughtful habits and a better understanding of how our bodies respond to colder weather, we can strengthen our defenses and stay well all season long.

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Below, Elizabeth Chan, MD, family medicine physician, answers some of the most common questions about boosting immunity during the winter months — and shares practical steps anyone can take to stay healthier.

Is it inevitable that most people get sick in the winter, or can we really take steps to prevent it?

It’s not inevitable, but it is more common for a few reasons. During the colder months, we spend more time indoors and in closer contact with others, which makes it easier for viruses to spread. Many viruses also thrive in colder, drier air. When humidity drops, the lining of the nose and throat can dry out, weakening one of the body’s first lines of defense.

Shorter days also mean less sunlight — and therefore lower vitamin D levels — which can make the immune system less effective. The good news is that there’s a lot we can do to stay healthy. With small, consistent habits, it’s absolutely possible to reduce your risk of getting sick.

What are your top recommendations for boosting immunity during the colder months?

Start with the basics: get enough sleep, eat well, stay active, and wash your hands — a lot. Handwashing remains the number one way to prevent the spread of germs.

Aim for seven to nine hours of sleep each night, eat a balanced diet filled with fruits, vegetables, whole grains, and lean proteins, and make time for regular movement. Even something as simple as a brisk walk can improve circulation and help immune cells move more efficiently throughout the body. All these small steps work together to keep the immune system strong.

Do sleep, hydration, and exercise really make that much of a difference?

Definitely. Sleep, hydration, and exercise are the foundation of good health — especially in the winter. Getting enough rest allows the body to produce antibodies and proteins that fight infection. Staying hydrated keeps airways moist, helping flush out germs. And regular movement — walking, stretching, or light cardio — helps immune cells stay alert and ready to respond.

Are there any specific vitamins or supplements you recommend?

Vitamin D is an important one, especially in the winter months. With less sunlight exposure, many people become deficient, which can weaken the immune system. If bloodwork shows low levels, a vitamin D supplement can be very helpful.

Vitamin C is another great option to support immune health and recovery. It’s easy to get from foods like oranges, berries, and kiwis, but supplements can be useful if your diet falls short.

How often should people change their sheets or clean their living spaces to avoid getting sick?

There’s no strict rule, but changing sheets and pillowcases at least once a week is a good habit. Germs and allergens build up more easily when everyone is indoors. It also helps to regularly disinfect high-touch surfaces like doorknobs, light switches, phones, and remote controls. A clean environment supports overall wellness and just makes your space feel better.

Want personalized support to stay healthy this winter? Find a doctor

Posted December 5, 2025