Getting sick is a part of life. It’s gotten us out of school, ruined plans for that big party, and kept us up in the middle of the night. In fact, most adults average two or three respiratory infections per year.
But the fact remains: Sometimes you’ve got obligations that can’t wait. And if getting healthier in the New Year is one of those, it can feel like a big setback to be sidelined by a cold as soon as you’ve adopted your new health-focused groove.
In general, if you’ve got a little cold, it’s best to scale back, decreasing both the intensity and duration of the workout, says Lipi Roy, M.D., an internist at Massachusetts General Hospital and instructor at Harvard Medical School. But there are also instances when you should take time off completely. Here’s how to know the difference.
The Need-to-Know 
Remember this easy rule: If your symptoms occur around your neck and above, it’s OK to do a light workout. If you’re sick below the neck, stay home.
We’ll provide a few more details: If you have a common cold or mild upper respiratory symptoms—like a runny or stuffed-up nose—it’s generally all right to work out. “In fact, there’s evidence that a light run followed by a lukewarm or hot shower may act…