Written by Cami Salisbury | Reviewed by Fit with Food Dietitians

Hydration is undeniably important. You’ve likely heard this before, but still, why is hydration important, and how do we know if we’re properly hydrated? Achieving proper hydration requires a careful balance of maintaining the body’s fluid levels at the ideal state of euhydration, or standard level of hydration. This balance requires avoiding both dehydration and overhydration. While discussions of hydration frequently center around the significance of water consumption, which is undoubtedly crucial given that it comprises anywhere from 50% to 75% of our body composition, the concept of staying adequately hydrated extends beyond simply drinking water.¹ This includes foods that we eat, especially those high in water content like fruits and vegetables, or beverages such as non-fat milk or 100% juice.² Before we discuss individual hydration needs, let’s dive into why proper hydration is vital to our health. 

Why is hydration important?

Water is an essential component for every bodily system. Sufficient fluid levels help sustain blood volume levels and facilitate effective blood circulation, in other words, good hydration allows your blood to flow through your body. This circulation is needed to deliver electrolytes and a variety of nutrients to cells throughout the body, as well as regulating body temperature and ensuring you don’t overheat, while also filtering waste products through the kidneys, such as urine.³ Adequate fluid consumption is also necessary for lubricating joints, assisting with the digestion of food, and maintaining skin elasticity.^2,3 Finally, sufficient hydration will contribute to muscle function and energy and endurance levels during physical activity, especially for athletes that perform at a high intensity for long periods of time.²

Defining Hydration: How do I know when I’m properly hydrated?

So how do you know if you are getting enough fluids throughout your day? One indication is the color of your urine. Remember how water is needed to filter waste products like urine out of the body? Well, the goal is for urine to be a pale yellow color. Surprisingly we don’t want to see perfectly clear, colorless urine as “Drinking to keep urine clear or maintain body weight may lead to overhydration”.⁴ Alternatively, if it appears darker or more amber toned, like apple juice, you may be dehydrated.⁵ 

Signs of Dehydration

Signs of dehydration go beyond just urine color though. They may include symptoms such as intense thirst, headaches, or dizziness, reduced cognitive ability, like poor concentration or alertness, along with irritability and moodiness.² Dehydration will also manifest as exhaustion or fatigue, reduced skin elasticity, constipation, and even urinary tract infections (UTIs) or kidney stones. All of these dehydration symptoms certainly don’t sound ideal, but what happens if you drink too much water? 

Signs of Overhydration

Although overhydration is less commonly encountered in the general population, it remains a case for concern. Many overhydration symptoms mirror those of dehydration, including headaches, fatigue, and exhaustion. However additional signs include frequent urination, nausea, vomiting, muscle cramps, and confusion from cells swelling with water in the brain.⁶ The most concerning sign of overhydration is the occurrence of hyponatremia, or dangerously low levels of sodium in the blood.^3,5 Sodium is an essential electrolyte that helps maintain the balance of fluid throughout the cells in the body, so when sodium drops to unsafe levels this may lead to severe conditions like seizures, coma or even death if left untreated.⁵ 

Determining Personal Hydration Needs

At this point, it’s evident how important maintaining stable hydration is, but how much water, or more specifically fluids, do you need each day? Unfortunately, there isn’t a one-size-fits all answer, and the popular advice to “drink 8 cups of water per day” is not going to meet the hydration needs for everyone since various foods and other beverages also affect your hydration status. Furthermore, your age, lifestyle factors, and physical activity play a significant role in determining your unique hydration requirements. So, whether you are looking to alleviate constipation, improve energy levels, or are an athlete focused on proper hydration, consider connecting with a dietitian to help reach your goals. 

References:

1. Popkin BM, D’Anci KE, Rosenberg IH. Water, Hydration, and Health. Nutrition Reviews. 2010;68(8):439-458. doi:https://doi.org/10.1111/j.1753-4887.2010.00304.x
2. Brinkman JE, Dorius B, Sharma S. Physiology, Body Fluids. StatPearls Publishing; 2023. https://www.ncbi.nlm.nih.gov/books/NBK482447/
3. Nelms M, Sucher KP. Nutrition Therapy and Pathophysiology. 4th ed. Boston, MA: Cengage; 2020
4. Hew-Butler TD, Eskin C, Bickham J, Rusnak M, VanderMeulen M. Dehydration is how you define it: comparison of 318 blood and urine athlete spot checks. BMJ Open Sport Exerc Med. 2018;4(1):e000297. Published 2018 Feb 1. doi:10.1136/bmjsem-2017-000297
5. How much water do you need to stay healthy? Mayo Clinic. October 12, 2022. Accessed September 18, 2023. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/water/art-20044256. 
6.  Zelman KM. What Happens When You Drink Too Much Water? WebMD. May, 2023. Accessed September 18, 2023. https://www.webmd.com/diet/what-is-too-much-water-intake.