Are You A Salty Runner? – Low Sodium Levels in Runners

By Rick Morris

Sodium levels in runners is a fairly unknown subject. Some runners hate to run in the heat – others love to. I am on the side that likes to run in warm weather. My muscles feel stronger and more relaxed when I run in warm weather versus cold weather. I sweat a lot when running in hot weather, which is a good thing. Sweat is your body’s way of keeping you cool. The sweat evaporates and cools your core temperature.

While I like to run in warm weather, many of my friends and clients would rather run when the temperature is cooler. There is good reason for that. They tend to have problems with muscle cramps and dehydration when they run in a high heat environment. Why do some runner’s have problems when running in the heat while others don’t? How can some athletes complete a hot weather marathon with no problems when many others must drop out due to dehydration or muscle cramping? Part of the answer might be as simple as the taste of your sweat.

That’s right – how does your sweat taste? While this may not sound especially appetizing it is a good way to find out if you are a salty sweater. All runners do not lose sodium at the same rate. Some lose a little while others lose a lot. There have been several studies conducted to determine the rate of sodium loss in athletes. All of the studies have shown the sodium losses can vary greatly from athlete to athlete from around 2g per hour to over 10g per hour.

Is sodium loss really a big deal? Yes – It can be. Low sodium levels can cause muscle cramping, dehydration and hyponatremia. Hyponatremia is a potentially dangerous condition caused by low blood sodium.

When you take into account the fact that our average daily sodium intake is 8 to 12 grams it is easy to see how a salty sweater can get into trouble when running in hot weather. How do you know if you are a salty sweater? The easiest way is the taste test. Does your sweat taste salty or does it sting your eyes? If so you may be a salty sweater. Another way to tell is to look for salt stains on your workout clothing or salt residue on your skin. If the residue is there it is a sign you may be a salty sweater. Another sign of a salty sweater are frequent muscle cramps or problems with dehydration.

If you are a salty sweater there are a couple of strategies you can use to protect yourself.

Always consume a sports drink when you are running in warm weather. The electrolytes and sodium in these drinks will help keep your sodium levels replenished. Drinking plain water will further dilute the sodium concentration in your blood that is already low due to your salty sweat.

Increase your dietary consumption of salt. While this goes against most healthy diet recommendations, it will help top off your sodium levels. Try to consume healthy high salt foods such as pretzels, soups, canned vegetables, whole grain crackers and nuts. Avoid the unhealthy high salt foods like packaged meats, hot dogs and fast food.

There is new research that suggests salt loading before a hard training run or competition will improve performance in the heat and decrease the adverse effects of being a salty sweater. One recent study (Medicine & Science in Sports & Exercise. 39(1):123-130, January 2007) investigated the effects of sodium loading on eight distance runners. The study found that sodium loading increased the runner’s plasma volume and resulted in increased exercise capacity and a reduced feeling of perceived strain. This is a relative new area of study and more research needs to be done but the early investigations seem to show positive effects of sodium loading.