Water is essential to life for cells, tissues, and organs in the human body. Water aids in the transportation and nutrients through the body, helps maintain blood volume, takes a part in body processes like digestion, and cushions vital organs that include the brain.

Keeping the balance of water intake and output in our body is carefully regulated by autonomic systems (those activities we can’t control), although we also must play an active role in hydrating our body. Without water, our organs would eventually shut down and die.

Why exactly do we need water?

Water is a necessity for numerous body functions such as:

  • Muscle movement and joint mobility
  • Nerve responses (nerve cells, like other cells in the body, require water to function properly)
  • Digestion
  • Metabolism
  • Excretion
  • Growth

In order for body systems to maintain life, several components are necessary, including:

  • Water
  • Nutrients
  • Oxygen
  • Adequate temperature

Water makes up 50% to 70% of our body weight and is the single most common and abundant chemical substance in the human body. Water not only provides the ideal environment for chemical reactions, but also serves as a fluid base for bodily secretions and excretions.

In order for our body to stay properly hydrated – and to perform vital functions – our water intake must equal water output. Of course, the amount of water intake is influenced by daily habits, exercise, and environment, but the average intake by adults who do hydrate properly hovers around 2500 mL.

What happens if we don’t get enough water?

Inadequate water intake leads to dehydration. Even slight dehydration can negatively affect motor coordination, attention span, memory, and mood. Dehydration can lead to headaches and fatigue.

If you don’t drink enough water every day, your blood can grow thicker or more concentrated, making it harder for your heart and the cardiovascular system to maintain adequate blood pressure.

Long-term or severe dehydration can lead to dangers for all body systems but most importantly brain function and cardiovascular function.

Daily needs for water depend on body composition, diet, metabolism, as well as the climate and age. Based on guidelines of the Institute of Medicine, aim for 2 to 3 L a day to help maintain health.