In 1996, the American College of Sports Medicine (ACSM) had implemented a ‘zero percent hydration’ rule that dictates: the weight lost during exercises must be replaced if health is to be protected and performance is to be optimized.  It was portrayed that fluid ingestion was the be-all end-all of exercise induced heat illness. They noted that the thirst mechanisms in humans was slow, and that athletes regularly drink too little prior, during, and post exercise. Also, every athlete, regardless of weight, height, etc. was to have the same fluid ingestion guidelines. These may have not been exactly evidence-based.

Hyponatremia is the state in which there is a low concentration of sodium in the serum. It is not as you think though. It is not exaclty a loss of overall sodium in the system (though we will lose some through sweat and urine), but it is often induced by too much hypotonic fluid uptake. We are essentially diluting the body’s serum. Symptoms may or may not be present. Some indiviuals may be symptom-free in early stages, though it may progress to cerebral edema, noncardiogenic pulmonary edema, altered mental status, and death.

History:

• 4+ deaths in the military between 1989 and 1996 – recruits were encouraged to consume 1.8L of fluid per hour of time spent in temperatures above 30C.
• 2 USA physicians – too healthy??
• 2002 had 2 female runner deaths, one each in Boston and Washington Marathon
• 2 college students died participating in a hazing requiring downing gobs of water
• 2007 – a 28 year old female died while competing to see if she could drink 2 gallons in a short period of time, without going to the bathroom

 Who’s at Risk?

A couple of nephrologists from the University of Virginia have outlined some of the risk factors based on current evidence:

• Exercise duration over 4 hours, or slow running/exercise pace
• Female gender – postulated that it may be moreso due to body mass
• Lower body weight
• Excessive drinking (>1.5 L.h) during the event
• Pre-exercise overhydration
• Abundant availability of drinking fluids at the event
• Use of NSAID anti-inflammatory medications
• Extreme hot or cold environments

What do we do? Drink or no drink?

If you are serious about running in a race, you will have to practice your long distance runs before the race date. Weigh yourself before your run, monitor exactly how much water you have ingested during your run (drinking only when feeling thirsty), then weigh yourself immediately after the run.

There should be a net loss of body weight or an unchanged body weight. If your weight has increased during the run, you have consumed too much water and are at risk of EAH. Try to figure out the amount of fluid you will need through the run with this test.

DO NOT overhydrate the day before the race. During the race, I was explained that you should grab the small amounts of electrolyte solution (small amounts, to maintain the small amounts of salt lost), and take the water handed out and throw it onto your head (helps cool you down!).

This seems like a topic that I can write forever upon! I normally would write up the reference list, but wil hold off for now, because it has gotten pretty late! If interested, send me a message and I’ll compile the list for you!

TO ALL THE WEEKEND RUNNERS:

Thanks for reading!!