I'm not a runner but I recently started trying to get back in shape. I'm not in bad shape but just hadn't done much cardiovascular activity for a while. I'm in my 20's and have an average build, not fat or anything. I usually run every other day or every 3 days, and run about 2 miles each time.
Here's the problem. I will finish my run at the park and then drive 7 minutes back home. It is when I get out of the car to start walking into the house that sometimes, not every time, but occasionally I will feel light headed. The lightheadedness continues for only a short time and then I feel fine, that is, unless I sit down and get back up again, or lie down and get back up again. It is after these runs where I feel lightheaded that starting about 20-30 minutes or so after I get back home that I start having problems with my vision. I don't know if it's an acute blindess or what, but the problem can best be likened to the effect you get from looking into a bright light and then looking away. But instead of seeing a bright spot there's just nothing. It effects a small area of my center vision only, my peripheral vision is unaffected. It is bad enough that it makes it a little difficult to read. And this problem persists usually for about 50 minutes or so.
I had thought that I only had this problem when starting to run after long periods where I didn't do any cardiovascular activity. That is when it has happened in the past, but I have been running now for a couple weeks and it happened again today. One thing I have tried to do to prevent it is after I get back home I sometimes force myself to breath deep for an extended time, but I frequently get caught up in reading and forget to continue breathing hard and sometimes the problem starts then. I thought that maybe I should be breathing more and my body for some reason just fails to tell me the proper rate I should be breathing, but I have no idea.
It is still an uncommon occurence, but the fact that it even happens is very concerning. Does anybody know anything about this?