hyponatremia

Hyponatremia

An elecrolyte disorder which occurs when the sodium level in the blood drops below 110mEq/L (Normal is 135-145mEq/L).

Causes

• Excessive water intake.
• Inadequate sodium intake.
• Loss of sodium rich body fluids.
• SIADH (Syndrome of Inappropriate Antidiuretic Hormone Secretion)

Symptoms

• Anorexia
• Vomiting
• Nausea
• Confusion
• Lethargy
• Headaches
• Seizures
• Osmotic transfer of water into the blood
• Brain swelling
• Coma

Treatment

Treatment for hyponatremia varies based on the causes and extent of sodium depletion. Although there are many web based 'treatments', if you suspect that you may be suffering from hyponatremia, please see your doctor immediately.

Seriously though, for an otherwise healthy adult person with normal renal function to suffer from hyponatremia from water overdose, it takes a water intake of somewhere close to 20 litres of water per day, a feat most would balk at. Equally unlikely as a cause of hyponatremia in most Americans is hyponatremia secondary to a dietary deficiency of sodium as the average Western diet nowadays contains far more than the daily requirement of sodium.

This leaves sodium losses and SIADH as the most common causes of hyponatremia. The treatment for hyponatremia is to find and treat the underlying cause and to consider fluid restrictions until the hyponatremia is corrected.

Conventional running wisdom emphasizes drinking lots of water while racing (and holds that water is more or less as good as various enhanced sports drinks and supplements), which is fine advice for most races. However, the very prolonged nature of marathons and ultra-marathons, with runners going for hours at full effort, can result in serious sodium depletion through sweat, which can actually be exacerbated by the amount of water runners will take in during the race to stay hydrated. Until recently many marathoners who collapse have been incorrectly tagged as being dehydrated and given more water, which too can delay recovery.

The moral of this story is: if you intend to run for more than 90 minutes at a pop, take a few pretzels along or drink a bit of an electrolyte containing sports drink (Gatorade or what have you) along with your water.