» Hyponatremia in Endurance Athletes

Marathon running is one of the fastest growing sports in America, and San Diego just hosted its own Rock and Roll Marathon.  For seasoned runners and novices alike, there are medical issues to consider before participating in a marathon.  One of the most serious concerns is exertional hyponatremia, which is a dangerously low concentration of sodium (salt) in the blood.

Symptoms of hyponatremia include: malaise, fatigue, muscle cramps, weight gain, confusion, and nausea. In the most severe cases, hyponatremia can result in cerebral edema, seizures, coma and perhaps even death.

So what causes healthy athletes to develop this potentially life-threatening condition?  Factors include:
•Drinking excessive amounts of water while exercising 3 or more hours.
•Gender: women’s smaller size and decreased sweat rate may make some women more susceptible.
•Not being acclimatized to hot weather.
•Taking non-steroidal anti-inflammatory drugs (NSAIDs) prior to an endurance event (the most common NSAIDs are Advil and Motrin).

In fact, a study conducted during a triathlon in New Zealand revealed that the 6 individuals who suffered from hyponatremia had each taken a NSAID prior to the competition. So be cautious with pre-competition medication!

Use these tips to avoid hyponatremia:
•Be properly (not overly) hydrated prior to competition. Drink water when you need it – not because you feel you “should” be drinking.
•Acclimatize to hotter environments. If at all possible, you should arrive 5-7 days prior to a competition to get used to the heat and humidity.
•Avoid taking NSAIDS prior to long hours of training and racing.
•Remember to include sodium for longer bouts of exercise. Try Gatorade, Powerade, pretzels and even salt tablets in moderation.
•Weigh yourself before and after long training bouts. You shouldn’t lose more than 3% of your body weight after a long training session, and you certainly shouldn’t weigh more.

When exercising, it’s important to stay hydrated, but don’t mindlessly drink.  Remember- you don’t need to guzzle water at every water station.

Written by Michelle Grenier MS, RCEP ATC, CSCS, CES. Michelle Grenier MS, RCEP ATC, CSCS, CES is the exercise physiologist for LWI Peak Performance and Lifewellness Institute. Michelle’s lifestyle is dictated by her passion for running.   She’s been running for 22 years, coaching athletes for 10 years and wrote her master’s thesis on Uphill Running Economy. Get an edge on your training program – visit  www.lwipeakperformance.com or email Michelle at elite@mylwi.com