Was hot out last Monday when I went for a run after work around 2030 hrs. Decided to go for a dip in the brand new pool we got for the kids, which was filled with arse snappin' cold water! Pool is 4' deep. I jumped in, other than real cold, all was good and refreshing....until the massive lower leg cramps that came on in the middle of the night! It was evil! Had to get out of bed and walk around a bit. Used my foam roller before work the next day! Lesson learned!!