Maybe you should braid the roots of your twists before you start twisting, that way the stay stretched even when you sweat.
Erhmm...you obviously missed the class where they taught that you must not get your hair wet.
Girl, I don't mess with chlorine or salt water. I recently went swimming and this is what I did. First I wrapped my head with Saran wrap making sure I just stopped short of squeezing my brain out through my ears. Then I wore a cap on top of that. And after all these precautions, I swam with my head out of the water and never even let it get wet.
When I first went to boarding school, I went swimming w/o a swimcap and then didn't shampoo my hair. I ended up with a brush for hair and had to get it cut off, and then shaved off at the barbers coz my cut had been quite uneven and ugly. I have never forgotten how cruel that swimming pool water was.
And I've been taking notes of what to coat my hair with when I go swimming, even though I will still enlist Saran wrap, a plastic cap and a swimcap to keep my hair "safe"
I don't know how you twist but if you twirled the strands before wrapping them around each other, the hairs strands would be locked in their respective strands and not tangle those of the other strand. So wetting them would not really affect them. If you were CWing as often as I tend to do when I wear twists, and you were doing the twists as I suggest, you'd find the strands stay separated...and that water is not the enemy.