Hmm... You mean you hike when you have a cold, flu, etc? (We're not talking "sick in the head" here, right?

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My thoughts on the subject: I have tried doing some exercise when I'm sick. Most recently this past winter when I had a bad cough. I always regret it. I may be starting to feel better from my cold/flu or whatever, but if I go exert myself on a hike, cross-country skiing, etc., then I just find myself getting worse again. When I have even the teensiest cold I try to take time off of work and everything else and "nick it in the bud" by resting, staying warm and drinking lots of fluids. The cough this winter was an anomaly, as I don't usually get sick--it lasted for weeks despite my best efforts to get rid of it.
One winter, an especially cold one, after I'd lived in Eagar for about 2 years, I had no car, and my job was in Springerville, a couple miles downhill from my house. Everyone seemed to be sick that year, and it was really cold weather, too, lots of mornings it was about 5 degrees when I was riding to work. Everyone at my job was really sick, and the hospital was full to bursting, and nobody could get a doctor's appt. But I never got the virus. I attributed this bit of serendipity to the fact that I was riding my bike in all sorts of weather, and I was pretty strong.
Anyway I am a firm believer in taking care of illness, and not taking it to work and spreading it around to your co-workers. This seems to be an unpopular opinion these days, as it seems to me every winter people bring their colds, etc. to work, and then make excuses about it. Also I'm a firm believer in going to bed early, and not using an alarm clock to get up with. You'll live longer, and much more importantly FEEL BETTER if you always take time to get whatever rest your body needs and asks for at the time.
People nowadays pressure themselves too much IMO. Take time to take care of yourself! You deserve it!