Survival skills
A human being can survive an average of three to five days without the intake of water. The issues presented by the need for water dictate that unnecessary water loss by perspiration be avoided in survival situations. The need for water increases with exercise.
Black Fast
The term "Black Fast" has a different connotation with writers within Classical Pentecostalism. A Black Fast is complete abstinence from food or water and nothing is consumed in its duration. Dr. Curtis Ward teaches that the Black Fast should never extend beyond three days because of ketosis, possible kidney damage, and dehydration. He further states that nothing in the New Testament says that they extended this type of fast beyond that limitation and that Christ's fast included water because "he was afterward an hungred" and was offered bread. If he had abstained from water he would have obviously craved water first and foremost. Dr. Ward states that the Black Fast, Hebrew Fast, and the Absolute Fast are synonymous terms.