These days, drinking fluids during exercise is considered normal behavior. The importance of drinking water was first documented during the construction of the Hoover Dam near Las Vegas in the mid-1930's. Unfortunately, the athletic community didn't catch on until the middle 1960's. In the late 60's and early 70's, the opinion of many began to shift and drinking water during exercise started to become commonplace. Nowadays, withholding water might even be considered negligent.