Why We Need Water: The Function and Impact of Water Consumption on The Human Body

Water is the base of all life on Earth. However, the real value of water is often understated and overlooked. To have a genuine, true appreciation for all that is H2O we must first understand the basics of what it is and how it plays a role in our bodies. Water aids in maintaining homeostasis through various physiological mechanisms, keeping the body balanced and functioning optimally. Water also accounts for roughly 60% of our total body weight and without it we would not be able to exist!

Homeostasis, in reference to our bodies, can be defined as “any self-regulating process by which biological systems tend to maintain stability while adjusting to conditions that are optimal for survival.” This self-regulating system is what our lives depend on, primarily altered by changes in total body water. Water plays a very vital role in this system and has many different cues to inform the body when in need. When it comes to water intake, humans consume water through various foods and beverages. Oftentimes when we are thirsty and go to drink a cool refreshment, it is because our body is giving us the cue that we are water deficient. Once the body gets the signal it needs water, it sends the thirst message as well as a message to reduce urine excretion therefore maximizing the current available water. The system also accounts for over-hydration. If the body is too full of water the signals flip, the body no longer sends thirst cues and instead signals the kidneys to excrete water to again achieve the coveted balance. Homeostasis and water also control blood pressure and heart rate. “Water intake acutely reduces heart rate and increases blood pressure.” These effects can last up to 60 minutes AFTER the consumption of water making it an easy reminder to drink regularly.

Considering the body wants to be in homeostasis constantly, it makes sense that the receptors recognizing slight changes to the balance are both sensitive and precise.  The smallest alteration in total body water can cause cells to shrink or swell to account for changes in the body. Body temperature also relies on sufficient water supply to maintain homeostasis and regulate internal changes. Through hydration, the body can respond to increased core temperatures by excreting sweat. Once the sweat breaks the skin barrier it begins to evaporate, therefore cooling the skin and lowering the core temperature that prompted the change. This is why it is important to consume fluids before, during and after being in a situation where your core body temperature increases. (exercise, hot climates, etc.) When living in an environment that is consistently hot such as Florida, it is especially important to make sure the body is hydrated.

When the body is water deficient it can have negative effects, the most serious being dehydration induced death. A lack of body water can lead to disruptions in cognitive functioning as well. Moderate dehydration can specifically affect “short-term memory, perceptual discrimination, arithmetic ability, visuomotor tracking and psychomotor skills.” The kidneys are also impacted by water deficiency in the body as the kidneys require water to remove waste from the blood and create urine to excrete the accumulated waste. When there is a lack of water it puts the kidneys at risk for high toxicity levels of waste they cannot dispose of and creates opportunity for the waste to reenter the blood stream.

Knowing the risks of limited/no water consumption it is even more important to take precautions to maintain homeostasis. Following Daily Recommended Intake levels and tracking water consumption are simple ways to ensure our internal balance is protected.


Water, Hydration and Health : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2908954/