Yael: Are you okay, Don? Don: Sorry,Yael . I just have a cold. Nothing, a little exercise can fix. Y: Wait, you're going to exercise even though you are not felling well? D: Sure.When I'm a little under the weather,I try to work up sweat,and then I usually feel better.You know the old saying about “sweating out a cold.” Y: Yes, but that's just folk wisdom, not science. Let me ask,do you have a head cold or do you maybe have a fever? D: I'm not sure.I mtght feel a litle warm. Y: I ask because if you just have a running nose or sore throat,it may be ok to do some moderate exercise for a half hour or so. But if they are achey and have a fever, then it’s better to rest.