I was swimming laps very regularly until just recently. I have been low carbing for a year, and was swimming up to an hour at a stretch, sometimes more. The only low carb problem I noticed was cramps in my feet after 40 minutes or more. Usually I could shake them off and keep going. I tried taking mineral supplements, which seemed to help, but not 100%. The cramping may not actually have been due to low carbing, but I never had this problem before, and I have been a swimmer on and off since I was a kid. Of course, maybe it's just old age, or too much exercise - I also run and use the stairmaster.

But alas, due to my allergies to chlorine and the lack of conveniently located quality pools where I live, I am giving up the pool for now. If I can ever afford one of those private swim in place pools, or if I somehow end up living near a pool that doesnt use chlorine, I'll happily jump back in!