As we know, our body consists of a large amount of water. More than 70% of the human body is fluid, and it is vital for the body to function successfully. Dehydration affects the physical and mental health of a person, and also accelerates the aging process throughout the body. If you experience any of these symptoms - fatigue, difficulty concentrating, headache, joint and muscle pain, constipation, skin dryness, hair and nail splitting - it is probably a fault that you are not taking enough fluid.