Age, Body Fat and Gender
How long you can survive without water also depends on how much total body water content you have. Total body water varies by age, gender and body fat. Men's bodies are composed of about 60 percent water, and women's bodies are composed of about 55 percent. Babies' bodies are composed of about 78 percent water. The higher your body fat, the less the percentage of fluid you have. The less body water you have, the less time you can survive without water.