Water constitutes about 70% of human body weight. Dehydration can occur when there is a loss of just 4% total body water, and a loss of 15% can be fatal! Almost all of your body’s major systems rely heavily on water to function and survive (Sargen, 2019).

Water is the most efficient and effective means of flushing toxins out of your body. Though water cannot neutralize toxins, it is a requirement for your kidneys and liver to properly flush toxins and waste out of your body!

“If the body does not have sufficient water, then metabolic wastes will not be removed as efficiently as they should. In essence, the body would be holding in toxins instead of expelling them, as is required for proper health” (Hess-Fischl, 2010).

Proper hydration is imperative to healthy physical and neurological development in infants and children. Studies have shown that dehydration impairs physical growth and cognitive development in infants and children (Merhej, 2018).

“Water has a relatively high heat capacity, meaning it can absorb a lot of heat before its temperature rises. This trait helps it to stabilize temperature in its surroundings. The water in every cell of the human body acts as a buffer against sudden temperature changes. Blood is largely composed of water, and it moves toward vital organs when the body needs to conserve heat, and toward the extremities and skin when the body is in danger of overheating. Water evaporates from the skin and lungs to cool the body” (Silbajoris, 2018).

Water molecules surround our genetic material known as DNA in a very specific way. Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) have discovered the quality of the hydration shell, which our DNA is encapsulated inside of, depends on the water content and influences the structure of the DNA itself (Khesbak et al., 2011). Our DNA is housed inside of water molecules in a systematic order to support DNA’s characteristic double-helix structure and conformation. Without the support of the structure, cells would be unable to follow the careful instructions encoded by DNA or to pass the instructions onto future cells, making human growth, reproduction, and survival impossible (Sargen, 2019).

“Cellular water content plays a major role in the mechanical properties and physiological functions of all cells” (Cells, 2018). Every cell on Earth is housed by a membrane. Water contributes to the formation of the membranes surrounding each cell (Sargen, 2019). “Water allows everything inside cells to have the right shape at the molecular level. As shape is critical for biochemical processes, this is also one of water’s most important roles” (Sargen, 2019).

“The brain, compared to the rest of the body contains more water mass, approximately 75% of all brain mass is water. Water is required to provide metabolic and structural support for cells and tissues, as well as being involved in the transport of essential nutrients and compounds, which are essential for proper neuronal function.

Studies have shown that cognitive function declines at mild water loss of around 2% body water loss, though this can be affected by individual differences relating to fitness levels and dehydration tolerance.

These include poorer concentration, increased reaction times, short-term memory issues, and negative mood changes. Such a mild loss of water from the body can occur simply as a result of routine daily activities especially in adults who consume only around 1L of water (or 4 cups worth) a day.

Other physiological symptoms of mild dehydration that affect the brain can include light-headedness, dizziness, headache, nausea, and fatigue. Many daily headaches can be attributed to mild dehydration” (Shabir, 2020).

According to LibreTexts (2020), water is the main constituent of the following bodily fluids that protect and lubricate tissues:

Cerebrospinal fluid: Water in cerebrospinal fluid which encompasses the brain and spinal cord, acting as a shock absorber to protect them from whiplash, or the force of an impact.

Amniotic fluid: The Amniotic fluid inside a gestational sack provides a layer of protection for a developing fetus.

Pleural fluid: Water in the pleural fluid lubricates the lungs to make breathing easier.

Digestive secretions: Water in digestive secretions allows for easier absorption of nutrients, and the passage of materials through the gastrointestinal tract.

Mucus: Water allows mucus to line the walls of the intestines which eases the movement of food along the gastrointestinal tract.

Synovial fluid: Water rich synovial fluid lubricates joints and facilitates ease of body movement.

Water is scientifically known as the “Universal Solvent”, which means it allows important bodily substances to dissolve. The dissolving of substances plays a key role in transportation and absorption in the the human body.

Dissolved substances include many materials such as ions, sugars, amino acids, vitamins, and minerals.

Our blood is the primary transport fluid/tissue in the body. Blood is predominantly composed of water. There are many important substances which are dissolved in our blood. These substances include oxygen, glucose, electrolytes, proteins, lipoproteins which are transported to cells to support basic biological functions.

Our metabolic waste products, such as carbon dioxide and urea, are dissolved in water rich blood to be removed from cells and to prevent toxicity due to waste build-up (LibreTexts, 2020).