"When a person is dehydrated, GENTLY using your thumb and pointer finger, pinch the skin together on the back of the hand to form a peak. In a person who is suffering dehydration, the peak will stay up in the peak position about twice as long as the skin of a person who is not dehydrated. The reason for this is the volume of blood in the blood vessels and volume of fluid in the tissues under the skin is insufficient to stretch the skin back to it's normal place."
