Why is Hydration Important?

Last Updated

September 9, 2021

The importance hydration for health and wellness cannot be overstated: the human body is composed of almost 60% water with the brain and heart containing nearly 73% water1. Without water, a human can die in a matter of hours if the conditions are extreme enough2. Even under more moderate conditions, a human cannot survive more than one week without water. Several essential bodily functions rely on water including digestion, removal of toxins, temperature regulation and cognition. Without sufficient water our bodily processes can be compromised or completely shutdown, rendering short and long term effects on our health.

A waterfall in the desert.
Water is synonymous with life in the desert.

Is Water Required for Digestion?

Taking a closer look at the role of water in digestion, water is responsible for facilitating the passage of nutrients into your cells. It starts by supporting the transport of food from your mouth to your stomach where food is broken down so that the nutrients are more accessible to your body3. Without enough water, your body will stop producing saliva, making it difficult to swallow and even increasing your risk for stomach ulcers4.  Once the nutrients are absorbed in the intestines, they are delivered to different parts of your body via blood which is, as you might have guessed, is nearly all water.  The remaining contents of your intestines exit the body with the help of water too, when dehydrated constipation becomes more likely. 

Water Transports Toxins Out of Your Body

Water is also essential for removing toxins from your body with the assistance of the kidneys. Toxins are captured as blood is filtered through the kidneys and then transported out of the body in urine. When dehydrated, urine will be darker and more concentrated, increasing the risk of UTIs. Staying in a well-hydrated state can also reduce the likelihood of kidney stones. Kidney stones do not form as easily when there is enough water present to keep the crystals in your urine from sticking together5. At the extreme end, severe dehydration can lead to kidney failure.

Backpackers with their hydration gear beginning a hike.
Backpackers develop a unique appreciation for the water when they have to carry a trips worth on their back.

Water is Required to Regulate Body Temperature

The body maintains a narrow internal temperature range which is necessary for optimal systems function. Here too water is crucial for preventing internal temperatures from exceeding that healthy range. When the body starts to heat up and exceed the ideal internal temperature, sweat is released from glands below the skin’s surface. The evaporation of the liquid on the skin’s surface has a cooling effect as the liquid absorbs energy from the body when converted into a gaseous form6. If not enough water is available in your body to produce sweat, it can impair thermoregulation which can have serious consequences, most notably organ failure. 

Does Dehydration Affect Mental Performance?

The case for hydration should be pretty strong by now, but as a final point, consider how water intake affects cognitive performance. Research out of Georgia Institute of Technology revealed that being dehydrated by just 2% decreases cognitive areas such as attention and immediate memory7. Researchers performed a meta-analysis of all available research on this association and found there was a statistically significant relationship in the data. While the relationship is not well understood, it should not come as a surprise given the well-documented impact of dehydration on many other parts of the body. 

The breadth and magnitude of water’s impact on the body is impressive. Continue reading our article, Optimal Hydration to understand how your body regulates its fluid intake and simple steps to prevent dehydration.


1“The Water in You: Water and the Human Body.” USGS, US Department of Interior, www.usgs.gov/special-topic/water-science-school/science/water-you-water-and-human-body?qt-science_center_objects=0#qt-science_center_objects. Accessed 6 Mar. 2021.

2Packer, Randall. “How Long Can the Average Person Survive Without Water?” Scientific American, Scientific American, 9 Dec. 2002, www.scientificamerican.com/article/how-long-can-the-average.

3“Picco, Dr. Michael. “Water after Meals: Does It Disturb Digestion?” Mayo Clinic, 18 Apr. 2020, www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/digestion/faq-20058348?reDate=06032021.

4Admin, Web. “Avoid Dehydration This Summer: Your Digestive Tract Will Thank You!” Digestive Health Specialists P.A, 13 May 2020, digestivehealth.ws/avoid-dehydration/#:%7E:text=If%20the%20body%20is%20dehydrated,pass%2C%20causing%20pain%20and%20constipation.

5“6 Tips To Be ‘Water Wise’ for Healthy Kidneys.” National Kidney Foundation, www.kidney.org/content/6-tips-be-water-wise-healthy-kidneys#:%7E:text=Water%20helps%20the%20kidneys%20remove,this%20delivery%20system%20to%20work. Accessed 6 Mar. 2021.

6Baker, Lindsay B. “Physiology of sweat gland function: The roles of sweating and sweat composition in human health.” Temperature (Austin, Tex.) vol. 6,3 211-259. 17 Jul. 2019, doi:10.1080/23328940.2019.1632145

7WITTBRODT, MATTHEW T.; MILLARD-STAFFORD, MELINDA Dehydration Impairs Cognitive Performance: A Meta-analysis, Medicine & Science in Sports & Exercise: November 2018 – Volume 50 – Issue 11 – p 2360-2368 doi: 10.1249/MSS.0000000000001682

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