I don't know why, but when I go on a major physical activity on a weekend I am bound to get colds or a flu (at worst) sometime during the week.
This is what happened to me this week. I was feeling great on Monday morning. No muscle pain. No sniffs. I was feeling great! But that night, I had a hard time sleeping. I woke up several times and slept shallow most of the night.
Tuesday morning I woke up to an itchy feeling in my nasal area. The feeling when you inhale water through your nose! Not a good feeling. Nonetheless, I felt I wanted to run Tuesday night but didn't get to since it rained.
Wednesday, I wasn't better. We went to the airport to fetch my sister who just got back from Thailand. I stayed home the rest of the day.
Thursday, I was still having colds. But now it included a cough. I went to work that day since I can't stand doing nothing at home. Going home from work that afternoon, my eyes were feeling kinda warm as were my hands. I remembered the days when I had a cold, I'd go out and train parkour and my colds would be gone after. So, last night, not heeding what my parents said (BAD), I went out for a light run. About 5km. I went from Silang to AIIAS which is around 1mile and went around the campus twice which was another 2 miles which makes 3 miles or roughly 5km.. I was sweating after the run -- I was wearing a sweater, thick jogging pants and a funky hat -- and I felt kinda good. My colds were gone and I was coughing out phlegm.
When I got home that night, I realized a couple of things. First, after that much rest during the week, I actually increased my speed unknowingly. I was actually thinking that it was an easy run but it was actually faster than my usual. Second, I had a really nice rest that night. My dad had to wake me up this morning. I feel alot better than the rest of the week!! I should have run earlier and maybe I could have avoided several days of misery.
Maybe it's just me. Maybe just a coincidence. But I do believe that there is something in physical activities, maybe cardio-vascular activities that help strengthen the immune system. I haven't found scientific proof. But I guess it works for me and I glad it does.