Hydration, rehydration, replacing what’s lost through exercise and how much

Today I will discuss the role of water, electrolytes lost through sweating and their importance, signs of dehydration and hyponatremia, how to calculate sweat loss and tactics to employ to stay hydrated before during and after exercise.

Proper hydration is one of the most important aspects of physical activity. Athletes should employ hydration plans that take into consideration many factors, including sweat rate, climate and level and intensity of training. By Replenishing fluids and electrolytes, it can aid performance and prevent dehydration and hyponatremia.

Lets start at looking at the role of water In the body.

1- It makes up 60% of our body weight is one of the most vital and most neglected nutrients in our diet.

2- It plays many vital roles that directly affect the athlete’s health and performance.

3- Water is also the main component of blood, which is responsible for transporting nutrients (such as glucose), gases (such as oxygen) and waste.

4- Helps cool the body and maintaining its core temperature.

5- Water removes lactic acid from exercising muscles, and muscle glycogen holds water, which can be an advantage to well-hydrated athletes.

6- Water is also responsible for lubricating joints, moistening tissue and protecting body organs.

The athlete’s goal is to take in adequate amounts of fluid and electrolytes to compensate for the fluid and electrolyte losses during exercise.

We lose water when we Sweat, sweat is around 99% water; the other 1% is electrolytes. Electrolytes keep our cells, tissues, and fluids active and able to communicate within our bodies.

Key Electrolytes lost in through sweat include

1- Potassium / Controls fluid and electrolyte balance, assists in the conduction of nerve transmission and helps move glucose into the cell

2- Magnesium- Regulates muscle relaxation and helps other electrolytes travel through cell membranes

3- Calcium - Aids skeletal muscular contraction, nerve impulse transmission and the breakdown of muscle and liver glycogen

4- Soduim-  maintain the balance of water in and around your cells. It's important for proper muscle and nerve function. It also helps maintain stable blood pressure levels. If there is a lack of it you may suffer from hyponatremia.

Athletes can lose 115–2,300 milligrams of sodium per liter of sweat, To put this in perspective, one teaspoon of table salt has approximately 2,000 milligrams (mg) of sodium.

Factors that affect sweat loss

1- Sport

2- Skin and clothing

3- Environment

4- Heat and altitude

5- Level of fitness and diet

6- Body weight and gender- Women have more heat-activated sweat glands than men, but sweat less profusely.

7- Dehydration

A certain level of dehydration is inevitable with long distance training and racing. Athletes who lose 2% or more of their body weight during exercise are at risk for suboptimal performance. Inadequate fluid intake may result in fatigue, GI distress, reduced blood flow, increased heart rate and sometimes death.

Signs of dehydration include

1- Thirst,

2- Flushed skin,

3- Premature fatigue,

4- Increased body temperature,

5- Faster breathing and pulse rate, Due to lower blood volume, the heart compensates by beating faster to circulate more blood

6- An increased perception of effort and a decreased exercise capacity.

Other sign (that may occur later) include

1- Dizziness,

2- Chills,

3- Muscle cramping,

4- Increased weakness and

5- Labored breathing during exercise

Hyponatremia is a medical condition in which the concentration of sodium in the blood is lower than normal.

The signs and symptoms of hyponatremia as well as know how to prevent it from occurring

1- Nausea and vomiting

2- Headache

3- Confusion

4- Loss of energy and fatigue

5- Restlessness and irritability

6- Muscle weakness, spasms or cramps

7- Seizures

The combination of dehydration and hyponatremia is called hyponatremic dehydration.

To determine sweat rate, follow these steps

1- Athletes weigh them selves prior to exercise.

2- The athlete should exercise for at least one hour, while keeping track of the quantity of water he or she consumes.

3- After exercise, the athlete should re weigh themselves making sure to wear exactly what was worn before.

4- The athlete’s weight before and after exercise, as well as the amount of fluid that was consumed during the exercise, will be used to determine the athlete’s sweat rate.

5- Subtract the post-exercise weight from the pre-exercise weight in pounds or kilograms and convert to ounces , and add to the amount of fluid that was consumed during the exercise.

6- This will determine how much sweat was lost during exercise.

Tactics to employ before during and after

Fluid Replacement Before Exercise Athletes should consume fluids several hours before exercise. At least four hours before exercise, athletes should approximately 300ml per each 10 pounds of body weight, consume beverages with sodium (460–1150mg/liter) and/or sports nutrition products and sodium-containing foods to help to stimulate thirst and retain the consumed fluids.

It is important to consume the fluids slowly, rather than all at once. Consuming beverages with sodium will help stimulate thirst as well as retain fluids.

Fluid Replacement During Exercise

During exercise, the goal of drinking fluids is to avoid dehydration. This is accomplished by replacing fluids based on the athlete’s sweat rate and according to his or her level of thirst. Consuming fluids in excess of sweat rate should be discouraged. To increase gastric emptying, athletes should consume an average of 100ml/300ml of fluid every 15–20 minutes of exercise and consume 500–700 mg sodium per liter. The amount of fluid intake, as well as the rate of intake, will depend on the individual’s tolerance, the type of activity and the intensity of the activity

Fluid Replacement After Exercise

After exercise, the athlete should drink adequate fluids to replace sweat loss.

Coaches should encourage athletes to consume approximately 450 to 675 milliliter fluid for 0.5 kg of body weight lost during exercise. consuming foods and fluids that contain sodium to facilitate rehydration will improve hydration.

I hope that you enjoyed this blog and until next time stay healthy.


#Running #Practice #Payoff



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