When thinking of the essentials necessary for survival, things like food, air and shelter often come to mind. However, water is one of the most — if not the most — important elements to human survival. But why? Why is it that water is of such importance to all living things? What does it do for humans?

The adult human body is made up of up to 60% water; for some organisms, up to 90% of body weight comes from water. Humans, to survive and remain healthy, must consume a specific amount of water each day. An adult male needs about three liters of water per day, and adult females need about 2.2 liters per day. 

Various organs in the human body are predominantly made up of water; water composes 73% of the brain and heart, the lungs have about 83% water, the skin is composed of 64% water and muscles and kidneys are 79% water. Even bones contain water, with 31% of bones being watery.

Water serves multiple essential purposes in sustaining human life. It forms saliva to aid in digestion, regulates body temperature, acts as a shock absorber for the brain and spinal cord, helps deliver oxygen throughout the body, allows the body’s cells to grow and reproduce, flushes body waste (mainly urine) out of the human body, lubricates joints and helps keeps mucosal membranes moist. 

All of these functions are facilitated by water’s unique qualities and properties. Water’s ability to dissolve and break down substances into the valuable nutrients, minerals and chemicals involved in biological processes is necessary for cells in the human body to use such products. 

Surface tension is the property of water that allows the human body to transport these materials all throughout the body. Water is the liquid that processes the carbohydrates and proteins gained from food by metabolizing and transporting them throughout the bloodstream. As humans eat, water and other liquids help the body break down food to be absorbed into nutrients, and water is the liquid that transports waste material out of the human body. 

Water plays a pivotal role in human life. Without food, one can survive for eight to 21 days, but without water, one can only survive about three days. So, to maintain a healthy lifestyle and remain hydrated, prioritize your intake of water throughout the day.