This week we are discussing hydration. How much water should we be drinking? Watch this short video and read more below.
What is the importance of water in the body?
By weight, the average adult human is approximately 60% water, with ⅔ of it inside cells and the rest outside the cell: in the blood, in between cells, and in compartments such as the brain, intestinal tract, abdominal cavity, and eyes. In case you wonder why so much water is kept inside cells, let me explain.
The water inside the cell is kept not as free-floating but as polarized, meaning hydrogen and oxygen ions are oriented in a certain direction so that they are kept in place attached to oppositely polarized protein molecules, similar to the attachment of iron atoms to a magnet. This is the best way to protect intracellular proteins such as enzymes, which could otherwise be made nonfunctional when hydrolyzed. Enzymes use ions from the polarized state of water to move small protein molecules from one place to another for the construction of cell structures, antibodies, hormones, signaling molecules, etc.
Turgor created by water inside cells helps to support the structure of the organ the cells are part of. Without this, the organ will shrink, similar to a leaf that withers without a constant supply of water. Water outside cells helps with transportation in the circulation, lubrication and enzymatic action in the small intestine, elimination of stool in the colon, and for movement of waste through the kidney.
What is the significance of hydration?
According to a National Institute of Health study published in 2023, adults who stay well-hydrated appear to be healthier, develop fewer chronic conditions and live longer than those who may not get sufficient fluids. Although most people can tolerate a 3-4% decrease in total body water, it could impair cognitive performance in some. A 5-8% decrease can cause fatigue and dizziness. Loss of 10% of total body water can cause physical and mental deterioration and severe thirst. Dehydration can lead to high levels of sodium ions in the blood.
What are the causes of dehydration?
In people over age 50, the body’s thirst sensation diminishes with age, and the blunted response to thirst or inadequate ability to access free water in the face of excess free water losses seem to be the main causes of dehydration.
In humans during average-intensity exercise sweating can result in water loss of about 2 liters per hour. However, in warm or humid weather and during competitive sports water loss can be double that amount.
How does humidity affect water loss?
High humidity impairs heat exchange efficiency by reducing the rate of moisture evaporation from skin surfaces. The opposite can happen under low humidity. Those who move from a high-humidity ambiance to one that has low humidity may not initially appreciate the need to consume more water because of reduced sweating which used to be a signal for water intake. In addition, low humidity can cause excessive drying of the skin and that of the mucous membrane in nasal passages as well as eye irritation.