I agree with SE. You can never wash your hair too much. Wash your hair after every workout. What happens when our scalp sweats is it secretes oil along with sweat (which is usually pretty salty). If you don't wash that away from your scalp it is going to build up and turn white. The oil with mix with the salt making a not so nice residue, and salt with harden when left to dry, so it becomes kind of crusty. It will coat your scalp and can cause major buildup, blocking your scalp from breathing. Don't be scared that you are washing too often. Your locks love being clean and will often times dreads better when they are. If drying is one of the reasons you are apprehensive about washing, make sure you workout on a day when you don't have much going on after, or you at least have time to dry with a blow dryer (if necessary). Try to workout in the morning so your dreads can dry throughout the day. If you workout at night, just don't go to bed with wet locks. Over time that will cause molding. I hope this was helpful.