Dehydration Fatigue
What It Is and How to Prevent

fatigue at workDehydration can cause mind and body fatigue

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Dehydration fatigue is a common symptom for both athletes and non-athletes.

Many studies have confirmed that when an athlete becomes exhausted, it is often not only because of muscle fatigue but also from dehydration.

And this applies not only to athletes but to all of us in varying degrees, depending on our hydration levels.

Water is the most important source of energy in the body.

Dehydration causes the enzymatic activity in the body to slow down, producing tiredness and fatigue.

In addition, dehydration causes a reduction in blood volume. This makes the heart work harder to pump blood throughout the body and to deliver the nutrients and oxygen needed by the muscles, brain, and organs for basic functions.

Without adequate oxygen and nutrients to the cells, the body and mind become fatigued—almost always a key sign of dehydration.

Hydration Helps with Energy and Alertness

Health experts have estimated that almost 75 percent of Americans are not consuming adequate amounts of water on a daily basis. 

Moreover, according to a report published in the European Journal of Sports Science, almost 91 percent of the athletes studied were already dehydrated before starting their workouts. 

Exercise physiologists have proven that just 2 to 3 percent fluid loss equates to about 10 to 15 percent decrease in strength and endurance.

Thus, it is important to know some of the most common symptoms of dehydration, which are (1) thirst, (2) weakness, (3) dry mouth, (4) dizziness and (5) tiredness. 

Another key sign of dehydration is dark-colored urine. If the color of one’s urine is clear or pale yellow, it generally means the person is adequately hydrated. 

How to Prevent Dehydration Fatigue

The safest and easiest way to prevent dehydration fatigue is by drinking enough water on a daily basis, and always increase water consumption several hours before strenuous or prolonged activity or exercise.

When physically active, drink water at regular intervals of about an hour or two. Also make a habit of carrying a water bottle when you exercise and take small sips at regular intervals. 

Keep track of how much water you are actually drinking each day, and if you discover you are not drinking at least half your body weight in ounces of water, try to increase the amount gradually every week (by 8 to 12 ounces) rather than significantly increasing it at once. 

Water or Sports Drinks

For most people, drinking filtered, mineral-rich water is going to be more beneficial than commercial sports drinks.

Most sports and energy drinks are full of sugar, sodium, caffeine and a variety of artificial colors and flavors.

However, if you are involved in high-intensity sports or endurance activities that last for an hour or more, then some type of energy or electrolyte drink might be beneficial. 

To learn how to make your own electrolyte-enhanced water, see the recipe on this page Electrolyte Enhanced Water – Its Definition, Usage, and Benefits.


European Journal of Sport Science; Dehydration and sodium deficit during indoor practice in elite European male team players; 2010.

Further reading...

Proper Hydration Basics for Sports and Fitness

Return from Dehydration Fatigue to Dehydration Effects of Water Loss in the Human Body

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