Today I was in the pool for about 4 and a half hours. I actively treaded water or swam for a good portion of it, probably 3 hours, trying to burn some calories. When I went to enter it in fitday, I tried to underestimate since I know the cal counts are usually high. I entered 2 hours of swimming leisurely, no laps and got a cal burn estimate of over 800 calories!!! I was shocked and immediately tried to find other calculators and they all were in this range. Can this be anywhere near true? It didn't feel like work!