Quote:
But if your muscles aren't used to the exercise, you're not able to run for an hour to begin with. Six miles/10K isn't a distance most people can just wow! look! I can run! fall into-- you build up to that kind of distance. (So the initial muscle/water thing would have been several miles' capability ago in terms of fitness.)
Actually, I don't think that's probably true. First off, I have run for an hour and never covered 6 miles, so since we don't know your running speed, you might have run anywhere from a 5k to a 10k. Also, depending what other cardio has been going on, you might have built up the lung capacity to run without actually running. The first time I actually ran outside, I'd been using the elliptical daily for 6 months, and was able to easily run 4 miles without building up in any way (well OK, not easily, but I didn't die).
In fact, even if you've never run 2 days IN A ROW before, it might make a difference in terms of muscle swelling, no matter how often you'd run previously. Bottom line - if running every day is something you have done regularly before, it probably didn't cause a scale blip. But if it's different, in duration, in speed, in frequency, etc, it's very possible you have some muscle swelling going on.