When you have a cold, high levels of immune system chemicals called cytokines make you sleepier than usual. Don’t fight it: Shortening your sleep for even one night blunts the body’s immune response. If a cold is keeping you up, ask your pharmacist for a decongestant. These block prostaglandins, which experts suspect trigger the cough reflex.

2. Avoid intense workouts

Extreme workouts can make symptoms worse. But moderate activity like a 30- to 45-minute walk won’t hurt – and, by boosting immune function, could help you fend off your next cold.

3. Eat lightly

Your immune system dials back appetite during a cold, presumably to conserve energy and body heat for the big fight against viral invaders. Just be sure to drink plenty of fluids – they help thin mucus.

4. Relax

In a study of 55 people experimentally exposed to a flu virus, those who reported more stress developed more severe symptoms and released more of the immune system chemicals that cause inflammation. The same happens with cold viruses, say the researchers.