The Importance of Hydration

Many people underestimate the importance of hydrating your body with plenty of water, especially those in the gym that think exercise and diet are the only factors toward physical development. Water is one of the most essential and critical nutrients for the human body, as the human brain and heart are composed of 73% water, blood is 82% water, and the lungs are nearly 83% water (  Up to 60% of the human body is water and so clearly proper hydration plays a key role in muscle growth, recovery, weight loss and just maintaining a healthy body overall. Water serves a number of essential functions to keep us all going such as :

  • Acting as a building material and vital nutrient to the life of every cell
  • Regulating our internal body temperature through sweating and respiration
  • The carbohydrates and proteins that our bodies use as food are metabolized and transported by water in the bloodstream;
  • Assisting in flushing waste mainly through urination
  • Acting as a shock absorber for the brain, spinal cord, and fetus
  • Forming saliva
  • Lubricating joints


Each day, humans must consume a certain amount of water to survive and this amount varies according to age, gender, and geographic location. Generally, an adult male needs about 3 liters of water per day while an adult female needs about 2.2 liters per day, and some of this water is obtained through food. Even a 2% drop in body water can cause a small but critical shrinkage of the brain, which can decrease concentration and impair neuromuscular coordination, which will in turn reduce your mental and physical performance. Studies have shown that athletes who lose as little as this 2% in body water through perspiration have a drop in blood volume which results in the heart having to work much harder in order to circulate blood. This drop in blood volume can bring more serious symptoms such as fatigue, muscle cramps, dizziness, and nausea.


The general rule of thumb for the average person is that you need 1 mL of water per calorie consumed. So for a person with a daily caloric intake of 2000kcal, they’ll need about 2 liters of fluid. As mentioned above, the average adult male needs about 3 liters of water per day while an adult female needs about 2.2 liters of water per day. Now of course this is for the average person, and so if you are an advanced bodybuilder for example, your water intake will be much greater. Also, there are many other considerations to take into account such as your size, age, climate, workout intensity etc and so you’ll need to determine what the right amount of hydration is for you.


It’s important to strike a good balance between water intake and water outtake.

Dehydration: Water In < Water Out Overhydration: Water In > Water Out

Overhydration (or hyponatremia) can occur, when an individual intakes so much water that it causes a potentially fatal disturbance in the brain functions through the imbalance of electrolytes in the body. However, it is extremely rare to reach this level of overhydration, and usually occurs past the 5 gallon mark, which has typically only happened from radio contests or forced consumption so there is no need to worry about reaching this limit. Water balance is tightly controlled by the kidneys and alterations in water balance can occur from overhydration, sweating, increased intestinal loss, or urine output.

*** REMEMBER that if you are thirsty, you are already dehydrated!

Thirst is not perceived until your blood volume is decreased by up to 2%, and the thirst mechanism is further blunted as you get older. Therefore it is very important to keep your body constantly hydrated throughout the day, rather than waiting until you feel thirsty. Urine color is one of the key indicators in determining your hydration level, and so the darker your urine color, the more dehydrated you are.




About 75% of muscle tissue is water, and even the slightest drop in body water will affect physical and mental performance. And when you’re not performing at your maximum potential, you’re most certainly not growing at your maximum potential. Here are a few more facts about hydration and its effects on performance:

  • Water plays a vital role in removing heat from the body, and this allows you to feel less fatigued during your workouts.
  • Dehydration increases cortisol production in the body, and this decreases amino acid uptake by the muscles and decreases protein synthesis (A.K.A. no gainz)
  • Energy (Glycogen) levels are depleted far quicker when you’re dehydrated and your central nervous system (CNS) function becomes impaired. These leads to a decrease in performance, both mentally and physically
  • Since muscles are made primarily of water, dehydration can prevent muscles from properly contracting, reducing muscle tone. Proper hydration will improve the strength of muscle contractions and quicken muscle response
  • Proper hydration also helps in preventing sagging skin since water will fill out the muscles, resulting in clear, healthy and resilient skin.

Water also plays an important role in dieting, as studies have shown that restricting water intake causes your body to not only retain more water, but it also promotes fat retention. Due to its role in the transportation of nutrients and the removal of waste, your body can perceive the lack of water as major stress, and this could lead to the preservation of fat and water.  Water also helps control your appetite, as sometimes people may feel hungry even after a good meal, which indicates a lack of water. Drinking plenty of water during your meal or after can take this craving away.



  1. Upon awakening, drink at least 1 liter of water in the first hour. A lot of dehydration occurs while you’re sleeping.
  2. During the day, drink enough water so that your pee is light in color. Anything dark indicates dehydration. If you don’t have to pee at least once every 1-2 hrs that can indicate dehydration as well.
  3. 6 hours before the workout, start your hydration by drinking one glass of water every half hour. If you have to pee every 30 minutes and your urine is clear, you are at optimal hydration levels. Once hydrated, drink one glass of water per hour until it’s time to work out.
  4. Drink plenty of water at the gym and drink when you’re thirsty.
  5. Throughout the day, just remember to drink in total at least 1.5 gallons a day, and even up to 3 gallons a day as needed. Of course if you are an athlete, bodybuilder, powerlifter etc. your hydration needs will be much higher than the average adult.

Of course this is not a golden, “full-proof” plan so you will need to determine your hydration needs based on your size, perspiration rate, activity level, diet, and the temperature of your environment. So if you want optimal performance in the gym and a healthier overall body, be sure to hydrate your body with plenty of water!


Author Bio: Andrew Hong is the founder of ZUPP and OnTrack, spending the last 5 years in the fitness, health, and tech startup landscape.


One response to “The Importance of Hydration

  1. Pingback: The Importance of Hydration | H2minusO Blog·

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