Role of Water in the Human Body

Our body is made up of approximately 60% water. Our brain is ~85% water, blood is ~80% water and approximately 70% of lean muscle mass is water. Water plays an important role in all of these major systems and without water, they don't function efficiently. Even a mere 2% reduction in body water can decrease performance, affect short-term memory, focus and increase fatigue. 

Some of the most important roles of water in the body include:

Maintaining blood volume, nutrient transportation and waste removal

Water is the main component of blood and essential for transportation of nutrients and removal of waste in the body. Blood delivers nutrients such as glucose, sodium, potassium and amino acids to our tissues for cell life and function. Blood also carries toxins and waste products away from our cells to our kidneys and liver for filtration and removal. The kidneys regulate how much water we excrete or conserve to maintain blood volume and concentration.  

Chemical and metabolic reactions

Water participates in hundreds of important metabolic reactions that occur in the body known as ‘hydrolysis reactions’. These reactions break down the carbohydrates, fats and proteins in our food so that our body can use them for energy and create the building blocks of life.

Protects tissues and joints

Water helps keep sensitive tissues such as your eyes, nose, mouth and brain moist. It also functions like a lubricant and cushions joints like your spine and knee so they can easily move against each other.

Temperature regulation

Water has a large heat capacity which helps control body temperature and allows us to adapt to changes in environmental temperatures. If the environmental temperature increases above body temperature, the body begins to sweat. Sweat evaporates off the skin surface which releases heat and cools the body down efficiently.

Stay hydrated

Consuming water regularly throughout the day is important to prevent dehydration. We lose water through sweat and breathing (insensible losses) and of course, urine. The insensible losses account for ~50% of the total water turnover.

The average adult requires roughly 2-3L of water per day to maintain water balance and keep the body systems functioning efficiently. This will of course vary with different environmental conditions, physical activity and your individual metabolism. 

For ideas on how to drink more water, check out our 7 tips.