I used to get sick all the time. When I was in school, I’d have a cold several times per year! When I was in high school and even college, I was okay with missing a day or two (sometimes up to a week) but as I grew up and had more responsibilities getting sick became more and more of an inconvenience.
Not only that, I didn’t feel good!
But now I can count on one hand the number of times I’ve been sick in the last six years.
Pretty cool.
I guess my immune system is doing its job fairly well! I credit my exercise habit for the positive change.
Since I have been fairly active for years and exercise 5-6 days per week, I can credit my healthy immune system because of the fact that during moderate exercise immune cells circulate through the body more quickly and are better able to kill bacteria and viruses.
Score!
But just like nearly everything, moderation is key. Exercise is fabulous for warding off sickness, but overdoing it can cause the opposite effect.
Cortisol and adrenaline, known as the stress hormones, raise blood pressure and cholesterol levels and suppress the immune system. This effect has been linked to the increased susceptibility to infection in endurance athletes after extreme exercise (such as marathon running or Ironman-distance triathlon training).
I do need to keep in mind that with the marathon coming up on Sunday I need to pay extra attention to my recovery after the several-hour event.
After several months of training and slowly increasing mileage and hours running, this Sunday’s event will culminate in 26.2 miles run in hopefully less than 5 hours. This mental cut-off is only a time I set for myself; if something goes wrong, I’ll need to change the plan. One thing I’ve most definitely trained is my ability to be flexible as I run: I never know how I’ll feel that day, what my numbers will do, what the weather will do, how my mind will be. I’ve trained and learned as much as possible to be adaptable in as many circumstances as I can; time will tell how that goes!
For me, this means I get to take it easy after I cross that finish line. I don’t have plans for Sunday evening other than lying horizontal and having my husband man the Halloween door. I’m not sure I’ll be up for the constant flow of trick or treaters!
Maybe I’ll get a massage, too. I’ll be trying to avoid getting sick, you know… 
http://sportsmedicine.about.com/od/injuryprevention/a/Ex_Immunity.htm
