News From Terre Haute, Indiana

May 5, 2013

CHRIS DAVIES: Keep sodium levels in mind when sweating buckets

Chris Davies
Special to the Tribune-Star

---- — Salt, or sodium, is vital to life. Too much or too little sodium can cause all kinds of problems in your body. How much sodium do we need if we are exercising consistently?

If you are salt sensitive or hypertensive, always check with your doctor before experimenting with sodium prior to racing. As always, eat plenty of fresh fruits and vegetables to enhance the benefits of exercise.

Sodium is responsible for maintaining fluid balance inside and outside your cells, including blood. Consuming too much fluid prior, or during exercise, dilutes the extracellular sodium allowing too much fluid to seep into the cells. Affected cells expand resulting in hyponatremia, causing the brain to swell and is potentially fatal.

Athletes most at risk for hyponatremia are marathoners, triathletes, and other athletes who exercise longer than four hours. Typically, conditions might not be too humid or hot. The athlete is hyper vigilant about maintaining hydration levels to the point they consume far more fluid than they excrete in sweat. With blood sodium diluted, athletes may experience weakness, nausea, grogginess, and incoherence. If not treated they may progress to seizures, coma, and possible death.

Knowing your sweat rate and sodium loss rate during exercise are important in reducing risk of hyponatremia. Weigh yourself naked before and after exercise to determine your sweat rate. A one-pound loss equals 16 ounces in fluid loss. Post workout, you should consume ounce for ounce what you lost. Be sure to include a salty snack to hang on to the fluid you ingest.

Learning your sodium losses is a bit tougher. Maybe you have trained with the human salt-lick. He is the guy who resembles a salt block once the sodium has dried on his skin and clothes. On average sodium losses occur at a rate of 500 mg/pound of sweat with ranges being 220 to 1,100 mg. If you sweat heavily and resemble a salt block, you should lean toward the high end. Do the math to determine sodium losses over time.  

Replacing salt during exercise is relatively easy. Though electrolyte drinks can help, they usually are light on sodium content. Salty snacks are usually best. Since you’ll be racing for long periods of time and will need the extra fuel, baked pretzels are a good choice. You may find that you need even more sodium than you can consume in foods or drinks. You might want to experiment with sodium tablets, or concentrated sources of sodium. Use caution with these since they may delay gastric emptying and/or cause nausea. Always experiment with them in training before trying them in competition.  

Simulating racing conditions in training is crucial to reducing sodium losses. If you can’t spend the winter in Florida preparing for a spring marathon there are other ways to acclimate to heat. Overdressing during some long training runs can add some heat acclimating benefits. You’ll benefit from he extra sweat rate and have a psychological edge when you shed all those layers of clothing.

The non-athletic person needs about 500 mg. of sodium per day. Dietary guidelines recommend no more than 2,400 mg. per day.  

Feel free to sweat buckets during your racing and training but don’t forget about sodium.

Chris Davies, MS owns and is soon expanding Fitness Solutions, Inc. He can be reached at