Diseases & Conditions
Why are cold symptoms worse at night?
Ask the doctor
Q. My cold symptoms seem to be improving during the day, but at night they get worse again. Why does that happen?
A. Frustrating, isn't it? But you're not imagining that your cough and congestion ramp up just when it's time to hit the hay. The circadian rhythm — our 24-hour internal clock — signals immune cells to become more active at night. When these cells pinpoint germs, they fight them off by creating inflammation, which makes respiratory symptoms worse.
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About the Author
Toni Golen, MD, Editor in Chief, Harvard Women's Health Watch; Editorial Advisory Board Member, Harvard Health Publishing; Contributor
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