Women's skin is softer and moister than that of men, and they weep more and go to the toilet more often. But while women seem to have more water in their bodies, the opposite is the case, with the total body water of men in their 20s at 60 percent as against 50 percent for women. The reason why women get drunk more easily and have a harder time recovering than men is because they have less water in their body.

Yoon Do-kyung, a family medicine professor at Korea University Ansan Hospital, explains total body water is calculated based on the weight of body parts excluding fat. Men have less fat and more muscle than women, and that is why men have more water in their bodies.

Water accounts for 75 percent of muscle. "The amount of water intake depends on the level of physical activity, absorption and discharge of water. You don't have to drink more water just because you have more water in your body and maintain it. It is just that because men in general drink more alcohol and smoke more cigarettes than women, and get exposed to stress more often, they do need to drink more water," Yoon says.