Calories for swimming?

About how many calories does swimming burn in the following scenario?

• Lately I've been doing a lot of swimming, and I'l trying to figure out a ballpark figure of just how many calories it is that I'm burning. I have a round pool, its 4 1/2 feet deep, and what I do is put on music, and basically jog in the pool in one direction (creating a whirl pool). When the song changes, I switch directions and run back the other way against the current, and repeat for about 45 minutes. I switch up going forwards and backwards as well. I make sure to suck in my stomach, pump my arms, and kick my kees up as high as I can. Usually if do this for about 45 minutes I count it as 200 calories, but it HAS to be more than that. I burn 200 calories walking on an incline on my treadmill in about 25 minutes, and I know swimming puts a lot more resistance on your body so I've got to be burning more calories than on a treadmill or on an eliptical machine. So my question is, given the above, does anyone know about how many calories 45 minutes of simulating jogging in a round swimming pool, going back and forth against the current, would burn?

• Answer:

  Actually, your exercise regime is good. However, there is no way to determine the calorie expenditure without using a lot of scientific equipment. I would think that you're using far more than 200 calories. A swimmer swimming at the rate of 3000 yards per hour uses about 0.16cal per kg of body mass per minute. So, converting your body weight to mass, you divide pounds by 2.2. Your body mass is 59.1 kilograms. 59.1 x 0.16 = 9.5 cal per minute ... for 45 minutes (9.5 x 45 =) about 428 calories. According to livestrong.com a 130 pound person uses 472 calories water jogging for an hour so, my calculations are probably pretty close.