After exercising you should avoid drinking cold water but you should drink cool or room temperature water instead.
Drinking cold water after a workout or exercise can cause cramps in your legs as well as other parts of your body and may actually make you feel more tired.
When you drink room temperature or just cool water it's absorbed through your body better than cold water is.
If you drink cold water after exercise and get cramps or feel more fatigued then the cold water is likely to blame for it.
So drink cool or room temperature water for best results.