Sports Hydration and Fluid Replacement

Sufficient fluid intake is essential for exercise and optimum recovery.
Exercising causes the body to get warmer, so the body tries to cool down by sweating. This causes the loss of water and salts through the skin.

The amount an individual sweats varies from person to person and depends on:

Intensity and duration – longer and higher intensity exercise can cause greater sweat loss.
Environmental temperature – in hot, humid conditions sweat loss can increase.
Clothing – the more clothing that is worn, the quicker you are likely to heat up which may cause greater sweat loss.
Genetics – some people are just more likely to sweat than others.
Generally, the more a person sweats, the more they will need to drink.

Water Is The Single Most Critical Nutrient (Sports Hydration)

• The human brain is composed of 95% water;
• blood is 82% water;
• the lungs are nearly 90% water.

Water is also the single most critical nutrient for health, growth, and development.
It is not only the most important nutrient in the body, but also the most abundant.
Water is critical to the balance of all the body’s systems, including the brain, heart, lungs, kidneys and muscles.

How important is this balance?

A 2% drop in body water can cause a small but critical shrinkage of the brain, which can impair neuromuscular coordination, decrease concentration, and slow thinking.
Dehydration can also reduce endurance, decrease strength, cause cramping, and slow muscular response.
Mild dehydration is also one of the most common causes of daytime fatigue.

How common a problem is this in the United States?

Estimates are that 75% of Americans have mild, chronic dehydration.
This is alarming since proper hydration is required for maintaining healthy blood flow, proper kidney function, proper sodium/potassium /electrolyte balance and proper digestive functions.

Benefits of water for health

Water has many health benefits. Health benefits include the following:

• Healthier Skin:

Ensuring that you are properly hydrated will prove to be a far better solution to preventing or decreasing wrinkles.

• Healthier Joints:

Water is extremely important to the joints.
Synovial fluid contains water; if you become dehydrated, less synovial fluid is available to protect the joints.

• Healthier Teeth and Bones:

Water makes teeth and bone stronger. The additional fluoride added to the water supply provides extra strength and bone density to teeth and bones.

• Healthier Digestive System:

Water helps improve the digestive process and is imperative in maintaining a healthy urinary tract and digestive system.
Water is important to properly metabolize food.

1- Drinking sufficient amounts of water will help reduce constipation.
2- Drinking sufficient amounts of water will help the body process and transport nutrients and excrete any waste products once they are metabolized.

This is important for bodybuilders because they consume much larger amounts of food, vitamins, and supplements.
Exercise increases the amount of water lost through sweat (working out) and encourages a high metabolism (caused by increased exercise and more lean body mass).

• Reduces Fatigue:

Although water does not provide energy in the same way carbohydrates and fat do, it plays an important role in energy transformation.

Water is the medium in which all energy reactions take place.
Athletes who become dehydrated often find reduced performance in the days following.

• Helps In Weight Loss:

Water can suppress appetite naturally and increases the body’s ability to metabolize stored fat.
Studies have shown that a decrease in water intake will cause fat deposits to increase, while an increase in water intake can actually reduce fat deposits.

• Reduces Fluid Retention:

The body perceives dehydration as a threat to survival and begins to hold on to every drop.
Water is stored in extracellular spaces (outside the cell) which can result in swollen extremities (feet, legs, and hands).

Diuretics offer a temporary solution, but may cause more harm than good.
Diuretics will cause the elimination of water, along with many essential nutrients.

• Helps Build Muscle:

Water is needed to transport nutrients to your cells and transport waste out of the body.
Water helps form the structures of protein and glycogen.

If your body is dehydrated, your muscles will be deprived of electrolytes. without the proper water and electrolyte balance, muscle strength and control will also be impaired.

• Increases Muscle Tone:

Muscles are made primarily of water. Dehydration can prevent muscles from properly contracting, reducing muscle tone.
Increasing water intake will help prevent muscle cramping, improve the strength of muscle contractions and quicken muscle response.

• Reduces Risk Of Disease:

Studies have shown that increasing daily water intake has shown to decrease the risk of colon cancer by 45%, reduce the risk of bladder cancer by 50%, and it may potentially reduce the risk of breast cancer.
It is also believed that water may prevent kidney stones and urinary tract infections.

• Other Known Benefits:

Water also aids circulation, and helps regulate the body’s cooling system.
Improper hydration can result in muscle cramping, decreased strength and reduced endurance, severely impeding athletic performance.

How Much Water is Lost During Normal Body Functioning

The average amount of water lost per day includes:

• 16 ounces through respiration (average).
• 16 ounces through invisible perspiration (more if sweat is visible).
• 48 ounces through elimination.

How Much Water Is Enough

It is suggested that the average person—who is fairly inactive—requires a minimum of 8-to-12 cups of water per day.
However, this amount is far too low for bodybuilders and other active people.
Active people need much more to replace the fluid lost during exercise.

Depending on your size and perspiration rate, you lose about four cups of water per hour of exercise.
If you are working out in a mild climate, you are probably losing about 1/2 gallon of water through perspiration.

If you are working out in a hot climate, you can easily lose a gallon or more by the end of your workout and cardio session.
Bodybuilders need even more water to assist with the metabolism of the additional food and supplements consumed.

The major sources of water for the human body

The major sources are: liquids, foods, metabolic water and glycogen-bound water.


1- Liquids are by far the most abundant source of water for the body, accounting for about two-thirds of a person’s water intake per day.
2- Liquids can be readily taken in by the body without much digestive effort.

As the carbohydrate and electrolyte contents of a liquid increase, the length of time that it takes the liquid to empty from the stomach increases.


All foods consist of water and solids. The amount of water that a food contains depends on what the food is. For example, fruits, vegetables, cooked cereals, and milk are 80 to 95 percent water.

Meat cooked is about 75 percent water, while meat cooked well done is about 45 percent or less water.
Ready-to-serve cereals are about 3-to-5 percent water.
Generally, approximately one-third of daily water intake is from food.

Metabolic Water:

Metabolic water is the water that is produced in the body as a result of energy production.
Totals approximately 10 ounces per day, depending on how many calories are burned.
Metabolic water is produced from oxygen and hydrogen atoms.

The oxygen atoms are obtained during breathing.
The hydrogen atoms are obtained from the food that are broken down in the body for energy.

Glycogen-Bound Water:

Glycogen-bound water is stored in the muscles along with glycogen. About 3 ounces of water are stored along with every 1 ounce of glycogen.

Effects of dehydration on performance

Dehydration can, and does, affect athletic performance.
As the body loses water, its core temperature rises. This affects all the metabolic pathways, interferes with cardiovascular functioning, and reduces total exercise capacity.

When the water losses reach 1-to-4 percent of the body weight, athletic performance is reduced.
During a race, marathon runners can lose several quarts of water, representing 6-to-10 percent of their body weight.
If they do not properly rehydrate during the race, they will find that this amount of water loss can significantly impair their performance and possibly even put their well-being at risk.

Non-endurance sports such as football, basketball, hockey and soccer can cause similar water losses.

During tournaments, no matter what the sport is, athletes must make sure they increase their water intake to compensate for the prolonged exercise over the one or two days of competition.

Sports in which participants must meet weight-class requirements – boxing and wrestling, for example – are also associated with dehydration.
Wrestlers typically dehydrate themselves to make a lower weight class. This type of chronic dehydration decreases performance and adversely affects health.

Chronic dehydration will develop in any athlete who does not make an effort to remain adequately hydrated.
This means that the body can enter a state of dehydration and the person may not feel the sensation of thirst for several hours.

Therefore, you should not rely solely on your thirst response but should, instead, make a point to keep rehydrating your body all day long.

Some general daily hydration guidelines for athletes

Daily hydration is vital for everyone: endurance athletes, power athletes, and even nonathletes.
Table presents general water-intake guidelines for healthy, active individuals who exercise on a regular basis.
Researchers have found that the best way to determine the recommended daily water intake is to look at daily energy expenditure.


Table provides a minimum daily water-intake range to accommodate individual differences as well as climatic differences.
As the temperature climbs above 70 degrees Fahrenheit and the humidity above 70 percent, water loss will be increased due to increased sweating, especially during exercise.

Attaining and maintaining a peak hydration level starts by following the daily hydration guidelines discussed above.
For athletes competing in endurance events lasting more than 30 minutes, hydration supercompensation (water loading) before an event as well as hydration maintenance during the event have been shown to increase athletic performance.

Other athletes should make sure that they properly maintain their hydration levels leading up to the event, but they do not necessarily need to concern themselves with drinking water during their events.
One exception is athletes competing in tournaments that require participation in several events per day or several events over several days.

Table – Daily Hydration Guideline Estimates.


Daily Energy Expenditure Minimum Daily Water Intake
2,000 Calories 64-80 Ounces
3,000 Calories 102-118 Ounces
4,000 Calories 138-154 Ounces
5,000 Calories 170-186 Ounces
6,000 Calories 204-220 Ounces