Issue: 17.05 July/August 2007

Salt in their Sweat

Why do some athletes experience extremely high rates of salt loss when exercising? And how do we prevent them from getting cramps and heat illness? Here’s how to work with salty sweaters.

By Josh Hingst

Josh Hingst, MS, RD, SCCC, is Director of Sports Nutrition, Assistant Strength and Conditioning Coach, and Adjunct Professor of Sports Nutrition at Florida State University. He can be reached at: jhingst@fsu.edu.

Cramping, ice baths, IVs, and electrolyte supplements: For those of us who care for football athletes, these are signs that two-a-day practices are officially here. The majority of us, especially in the South, battle heat and humidity every year at this time. We have carted players off the field and placed them in ice baths immediately after practice and we have instructed athletic training students to hold down a 240-pound football player experiencing full body muscle cramps.

Educating every athlete about heat illness and providing fluids and electrolytes to help them avoid the dangers is an important part of our job. However, recent research indicates that some athletes need even more care in this area than others. They’re called “salty sweaters,” and when the heat strikes, they are more likely than other athletes to suffer from heat-related illnesses.

AT GREATER RISK
As the name implies, the biggest difference between salty sweaters and other athletes is that salty sweaters lose more sodium when they sweat—in some cases, a lot more. Consider this: In a study of 10 football players, sodium losses during a two-hour practice ranged from 0.8g to 8.5g. In another study of top male tennis players during matches on a hot, humid day, average sodium loss was 2.7g per hour, but one player lost 12g of salt in an hour.

Although they lose more sodium, salty sweaters have been shown to lose about the same amounts of chloride, potassium, calcium, and magnesium as non-salty sweaters. But the extra loss of salt has a dangerous implication: Research is increasingly showing that salty sweaters are at greater risk for muscle cramps and dehydration.

One recent study observed football players during a two-a-day practice and examined differences in fluid and electrolyte losses between a group of athletes with a history of heat cramps and a control group without a history of cramps. Results revealed that the cramping-prone group lost twice as much sodium as the non-cramping group: 5.1g on average for the cramping athletes, and 2.2g for non-cramping athletes during a single 2.5-hour practice. The authors concluded that sodium depletion is a recurrent theme in heat cramping and is most likely one of the factors contributing to its cause.

Dehydration can be another risk for salty sweaters, because it appears that they also tend to lose more fluid than non-salty sweaters. In the same study, fluid losses for those with muscle cramps averaged 1.49 liters per hour, while those without cramps averaged 0.99 liters per hour.

While more research is needed, it’s probably safe to assume that salty sweaters are also at greater risk of other heat-related illnesses such as heat stroke and heat exhaustion. Increased fluid and sodium losses limit the body’s ability to control its temperature, making all kinds of heat-related problems more likely.

IDENTIFYING SALTY SWEATERS
How do you know if an athlete is a salty sweater? The most scientific test is to use absorbent patches to collect sweat and employ specialized analyses to determine exact electrolyte losses. This is the method used by researchers. However, for athletic departments, this isn’t very practical. Fortunately, simpler methods are available.

At Florida State, we start by using our pre-participation physical exam. Since salty sweaters appear to get muscle cramps more easily, we use our questionnaire to identify athletes with a history of cramping. We also ask our athletes if they have noticed more salt loss themselves. Two simple questions can be sufficient to help identify athletes potentially at risk:

How often have you experienced muscle cramps during practice or games?
• Never
• Sometimes
• Frequently

When you sweat, does your sweat often sting your eyes or taste salty?
• Tastes Salty
• Stings Eyes
• Neither

Visual assessment can also be helpful. We’re careful to check for salt stains on practice clothing and salt on athletes’ skin during practices. Lastly, we keep records of athletes who experience muscle cramps during practices and contests and note how often they get them. Players who commonly succumb to muscle cramps, especially during two-a-day workouts or intense competitions, are flagged as salty sweaters.

At Florida State, I would estimate that 10 to 15 percent of our athletes could accurately be classified as salty sweaters. Generally speaking, of the 100-plus athletes on our football rosters, between 10 and 15 are identified as salty sweaters at risk for muscle cramps.

DIETARY STRATEGIES
Protecting salty sweaters from muscle cramps and heat illnesses means making sure they are replacing the extra sodium and fluid their bodies lose during exercise. Using electrolyte supplements is one way to do this, but a more natural and effective method is to help the athlete make changes to his or her diet. At FSU, we prefer to try this route first.

I encourage our salty sweaters to increase their consumption of healthy high-sodium foods. Good choices include pretzels, peanuts, baked potato chips, soups, canned vegetables, and lean luncheon meats. Unfortunately, many high-sodium foods athletes are likely to reach for—like regular potato chips, fast food, and frozen dinners—are highly processed and limited in nutritional value compared to fresh and whole foods. So be sure to give athletes specific advice on which salty foods are best. (See “Healthy Salt” below.)

Another way to increase sodium intake is to have the athlete use the salt shaker more often, applying salt to healthy, whole foods. Adding one teaspoon of salt to foods provides about 2,000mg of sodium, and this can be used as a guideline when increasing sodium intake through dietary means.

Athletes should also focus on caloric requirements. It is vital that energy needs are met, especially during periods of heightened training. Skipping meals or not eating sufficiently to fuel training can lead to cramps, so in athletes who are already at higher risk, eating enough takes on greater importance.

Of course, adequate fluid intake and proper fluid replacement strategies also warrant special emphasis. Similar recommendations for fluid replacement can be used for both salty sweaters and other athletes—they should replace 120 percent of fluid lost during exercise by taking in roughly 20 ounces of water or a carbohydrate/electrolyte/fluid replacement drink for every pound lost during exercise.

Because they may lose more fluid than other athletes, weighing salty sweaters before and after practices is important to determine their exact needs. They may lose four to six pounds while non-salty sweaters may only lose two to four. It’s also safe to go a little bit higher in the replacement recommendation, shooting as high as replacing 150 percent of the fluid lost (24 ounces for every pound instead of 20).

In some cases, however, dietary changes may not be enough, especially in extreme conditions such as football, where some players may average 5g of sodium loss via sweat during a single practice. That’s where supplements come in. During two-a-day practices or when training duration exceeds four to six hours per day, salty sweaters should be provided with 3,000 to 5,000mg of sodium immediately after practices in combination with fluid and carbohydrate drinks.

We use a pre-made product containing a combination of sodium and potassium. The powder is mixed with either water or a carbohydrate/fluid replacement. It is important to note that the electrolytes need to be consumed in combination with high fluid volumes.

When supplementing, each athlete should be treated individually. Initially, sodium supplementation should be done conservatively, with 1,500 to 3,000 mg. If the salty sweater continues to suffer from muscle cramps, the amount of supplementation can be increased. As mentioned, research has found that in very rare cases, an athlete can lose more than 10g of sodium per hour, and in these cases, up to 6,000mg of sodium supplementation is certainly warranted.

Another idea is sodium loading prior to competition. This is a relatively new concept, but early studies have produced positive results. Most research has utilized acute sodium loading protocols in an attempt to increase plasma volume, thereby improving heat tolerance and performance. Recent studies conducted in New Zealand have found sodium loading to increase plasma volume in both men and women. It has also been shown to reduce physiological strain, reduce perceived strain, and increase exercise capacity.

DANGER ZONES
When creating a strategy to keep a salty sweater free from heat illness across a season, it’s important to focus on managing the situations when their status is likely to put them at risk. The first variables to consider are exercise intensity and duration. Salty sweaters are most likely to run into problems when exercise duration hits six hours a day, such as during two-a-days in football. Because coaches also tend to place a considerable amount of emphasis on conditioning during these early practices, they often require a high level of intensity.

The next variables to consider are environmental conditions and equipment required for the sport. While it’s obvious that athletes practicing under the hot sun will sweat a lot, don’t forget about indoor sports like volleyball that may be having multiple practices in an uncooled gym. In addition, sports requiring special equipment can limit the athlete’s ability to cool their body, so they also pose a greater danger for salty sweaters.

Competitions can be another time when salty sweaters need extra help. It’s important to make sure they pay particular attention to their pre-competition sodium intake to help prevent them from cramping during competition. At Florida State, we begin supplementing our salty sweaters two to three days prior to a competition, increasing their daily sodium consumption by 1,500 to 3,000mg via dietary means or supplementation. This protocol is most common amongst football players, but it may also be warranted for other athletes who have a history of late-game muscle cramps.

Lastly, fluid and electrolyte replacement during competition takes on greater importance for salty sweaters. Carbohydrate, fluid, and electrolyte fueling during competitions is vital for salty sweaters, and paying sufficient attention to this can reduce the risk of muscle cramps.

In treating salty sweaters, the key is to remember that not all athletes are alike, especially when it comes to sodium losses during exercise. Special steps need to be taken to identify salty sweaters and help them understand their risks. Once they’re identified, it’s up to us to help them stay heat-illness free and performing up to their potential.

Sidebar: HEALTHY SALT
One way to make sure salty sweaters replace the sodium they lose during exercise is to encourage them to consume more salt in their diets by incorporating some high-sodium foods. However, not all high-sodium foods are created equal, so it’s important to help athletes choose the ones that won’t also add saturated fats, additives, and preservatives to their daily intake.

Healthy Choices
Pretzels
Peanuts
Soy Nuts
Baked Potato Chips
Whole Grain Crackers
Low-Fat Salted Popcorn
Soups
Canned Vegetables
Lean Luncheon Meats
Canned Tuna Fish
Canned Beans

Unhealthy Choices
Regular Potato Chips
High-Fat Deli Meats
Fast Food
Frozen Pizza
Frozen Dinners
Sausage
Hot Dogs
Pepperoni
High-Fat Canned Hash, Stew, or Chili
Instant Macaroni and Cheese

References for this article can be found here.

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