As autumn brings cooler temperatures and shorter days, your body undergoes real physical shifts. The changing weather can affect how you feel every day.

To learn how seasonal changes affect your health, WellTuned spoke with Dr. Ian Bushell, a medical director at BlueCross BlueShield of Tennessee.

“Our bodies are constantly adapting to the environment around us,” says Dr. Bushell. “When the seasons change, it’s a good opportunity to check in on our health habits.”

Why do more people get sick during cooler months?

Dr. Bushell: Many people think it’s because it’s cold outside. The reality is a little more complicated.  Several environmental and behavioral factors help spread germs during fall and winter:

• Viruses thrive in cold air: Respiratory viruses, including influenza (flu) and the common cold, spread more easily in cold, dry air.
• Dry air weakens body defenses: Cold air dries out the protective mucus lining in your nose and airways, making clearing germs harder for your body.
• More time spent indoors: Colder weather brings people inside. This increases close contact and opportunities for viral transmission.
• Indoor heating: Heating systems lower indoor humidity. This allows airborne viral particles to stay suspended and infectious for longer periods.

How else is our health impacted by cooler temperatures?

Dr. Bushell: If you feel increased joint stiffness or aches when the weather changes, you are not imagining it. When atmospheric pressure drops, tissues surrounding your joints may expand slightly. In joints affected by arthritis, inflammation or cartilage loss, even small tissue changes increase stress. This can cause discomfort or stiffness.

Cold temperatures also affect your heart and cardiovascular system. When you’re exposed to cold air, your blood vessels constrict to conserve body heat. Narrowed blood vessels increase resistance to blood flow. This causes blood pressure to rise and makes the heart work harder. People with high blood pressure or heart disease should take extra care during extreme cold.

Shorter days and reduced sunlight in the fall can disrupt your internal biological clock, known as your circadian rhythm. Specialized cells in your eyes rely on sunlight to signal your brain when to feel awake and when to rest.

Less sunlight can cause fatigue, mood changes, difficulty waking up or excessive sleepiness. Ways to maintain healthy sleep-wake cycles include:

• Spend time outdoors in daylight, especially during morning hours.
• Keep a consistent sleep and wake schedule every day, including weekends.
• Limit bright digital screens close to bedtime.
• Stay physically active throughout the week.

How can we stay healthy as the weather changes?

Dr. Bushell: The core basics of good health stay the same year-round: Stay physically active, eat a healthy diet, stay hydrated, get enough sleep, and keep up with recommended vaccines. During fall and winter, focus on a few simple extra precautions:

• Practice good hand hygiene and stay home when you’re sick.
• Maintain healthy indoor air quality and moderate humidity levels in your home. If it’s not too cold outside, consider opening a window occasionally. Or consider a high-quality HEPA (high-efficiency particulate air) filter for your home.
• Discuss the impact of weather changes related to chronic medical conditions like asthma, heart disease or arthritis with your doctor.

“Seasonal weather changes affect more than our comfort level,” says Dr. Bushell. “Small adjustments made at the start of a season may help you stay healthier and more resilient throughout the year.”

More from Dr. Bushell on WellTuned

Get more information about specific health terms, topics and conditions to better manage your health on bcbst.com. BlueCross BlueShield of Tennessee members can access wellness-related discounts on fitness products, gym memberships, healthy eating and more through Blue365®. BCBST members can also find tools and resources to help improve health and well-being by logging into BlueAccess and going to the Managing Your Health tab.