Exercise-Associated Hyponatremia

Introduction:

Hyponatremia is a condition when the complete serum sodium concentration in the body turns out to be below normal. This is a small variable value in different laboratories. Hyponatremia occurs when the serum sodium levels go below 135 mEq/L. This condition is referred to as a frequent electrolyte abnormality resulting from an excess amount of total water present in the body compared to the total amount of sodium present in the body. Some of the reasons that are frequently seen causing hyponatremia are vomiting, diarrhea, renal or liver diseases, congestive heart failure, etc. Exercise-associated hyponatremia is a term used when this condition is seen in athletes. It is seen in athletes mostly due to excessive sweating or water intake. It can be treated by managing proper fluid intake or by providing proper sports drinks for the athletes.

What Is Hyponatremia?

Hyponatremia is a term that indicates decreased blood sodium levels than the average level (less than 135 mEq/L). The ratio of sodium and potassium is essential as they maintain an electrolyte balance in the body, which is vital for proper body functioning. Due to this, an issue is faced in which water is increased, which dilutes the sodium value. As a result, water begins to penetrate the body tissues and cells, and they swell up.

Due to this swelling, serious issues can occur, especially in the brain cells, which could even result in seizures or coma. Hyponatremia can be caused by the intake of medications like diuretics (sodium excretion in the urine is increased), excessive consumption of alcohol, etc. It occurs in people with kidney failure, congestive heart failure, and surgery or people with endocrine diseases.

What Is Exercise-Associated Hyponatremia?

Exercise-associated hyponatremia is frequently associated with prolonged exertion during sustained, high-intensity endurance activities such as marathons or triathlons.

Exercise-associated Hyponatremia (EAH) is a condition in which the serum sodium levels are lower than the average (less than 135 mEq/L). This type of hyponatremia is frequently seen in athletes. Water retention occurs in various body cells and tissues as a result of this, due to which brain cells face multiple issues. This could result in seizures or coma.

Who Is Prone to Develop Exercise-Associated Hyponatremia?

Usually, people or athletes who drink lots of water during or after exercise in warm, humid environments are prone to develop this kind of hyponatremia. All athletes are not susceptible to hyponatremia. Only the athletes who sweat a lot or are more salty and those with an over-drinking habit. Athletes who are slow runners, triathletes, and cyclists have more time and are likelier to develop an excess water intake. This excessive sweat or salty salt can result in the sodium loss,

How Is Exercise-Associated Hyponatremia Caused?

The causative factors for exercise-associated hyponatremia can vary from person to person. Some of the reasons are listed below:

• The first reason associated with this is SIADH syndrome of inappropriate antidiuretic hormone (ADH) response. Due to this, urine production decreases, and more excellent retention of undigested fluids occurs in fluid overload.

• Another reason for this condition is the absorption of water into the gut.

• Intake of NSAIDs (Non-steroidal anti-inflammatory drugs) might cause changes in the kidney's function and reduce urine production.

• Intake of diuretics, which can cause increased sodium excretion through the urine.

• Increased loss of sodium through the sweat.

What Are the Symptoms of Exercise-Associated Hyponatremia?

The symptoms of exercise-associated hyponatremia are:

• Impaired Exercise Performance: This is likely caused by the altered status of brain cells due to water retention.

• Nausea and Vomiting: Nausea and vomiting are caused by increased pressure in the cerebral cells caused by a swelling in the brain cells or fluid accumulation in the stomach, intestine, or both.

• Headache: This is caused due to an increase in the intracranial pressure that occurs due to swelling in the brain.

• Altered levels of consciousness

• Seizures.

• Bloating, swelling of hands, legs, etc.

• Muscle cell breakdown.

How Is Exercise-Associated Hyponatremia Diagnosed?

Exercise-associated hyponatremia can be diagnosed with the help of a few tests, physical examination, and thorough history. This includes:

Urine test: With the help of this test, measurement of urine sodium, potassium, and creatinine concentrations is done.

Blood test: This test indirectly determines the total body water, the levels of sodium (Na+), and, in some cases, the hormones responsible for regulating water uptake by the kidneys.

Some Other Questions That Can Be Asked to an Athlete Are:

1. Which sports do they participate in, and for how long do they train?

2. What medications do they take?

3. What medical conditions do they have, and what surgeries did they have in the past?

4. How much alcohol do they consume?

5. Do they take any substances to boost performance?

How Is Exercise-Associated Hyponatremia Managed?

Doctors suggest small steps to correct the issue in case of mild symptoms. Treatment might be short-term or long-term.

Short-Term Treatment Is as Follows:

• Sports drinks (with a 4% - 8% concentration of carbohydrates) are advised for athletes. This provides fuel, which is much needed for the athletes' muscles performing in marathon or long run exercises.

• Immediate treatment is done in acute hyponatremia cases, which can result in cerebral edema.

• Limiting the intake of water.

• Adjusting or quitting medications.

• Treating the underlying issue.

Long-Term Treatment Is as Follows:

• Limiting the intake of water.

• Adjusting or quitting medications or adding another medication.

• Adding salt to the diet.

In moderate-to-severe hyponatremia, the patient is mainly advised to visit the hospital for proper medical evaluation and treatment. People with more severe cases of hyponatremia are advised to get sodium replacement intravenously (directly into the vein). They are also advised to limit water consumption.

Conclusion:

Hyponatremia is when serum sodium levels are reduced to the average level. Exercise-associated hyponatremia is linked with prolonged exertion during exercise. In most cases, this exercise-induced hyponatremia is due to excess fluid intake after the exercise, which results in dilutional hyponatremia. This condition can be diagnosed with the help of urine and blood tests by checking for serum electrolytes. It can be treated by regulating fluid intake or replacing it with sports drinks for athletes.