HERE’S EVERYTHING THAT AN ENDURANCE ATHLETE NEEDS TO KNOW ABOUT SODIUM

If you get super sweaty during your training workouts, don’t forget to replenish your body with this key essential mineral. Get to know why sodium is so important for endurance athletes.


BY: MARITA RADLOFF, MS, RDN, CSSD, LD

More and more people are becoming active and training for endurance races, including half-marathons, marathons, and triathlons. However, they might be neglecting a key nutrient that can make-or-break you on race day: sodium.

So what exactly is sodium?

Sodium is an electrolyte, along with calcium, potassium, magnesium, chlorine, and phosphate. Electrolytes are minerals in your body that have an electric charge, and exist in your urine, blood, tissues, and body fluids.

Electrolytes help to balance pH level, remove waste out of your cells and nutrients into cells, balance the amount of water in your body, and ensure that your nerves, muscles, heart, and brain function properly. These last two functions are where sodium plays its largest role. 

We mostly consume sodium from food through table salt, which is a combination of sodium and chloride, and excrete it through urine and sweat. The level of sodium in your body can become too low or too high depending on the amount of water in your body. 

If the amount of water you consume isn’t equal to the amount you lose, you can become dehydrated (too little water) or overhydrated (too much water). Certain medications, diarrhea, vomiting, sweating, and liver or kidney problems can also cause these imbalances.

How much sodium do we normally need?

The Institute of Medicine (IOM) recommends the Adequate Intake (AI) for the general population is 1500 mg of sodium per day. This is a number that you likely want to aim for especially if you have health conditions that require you to watch your sodium intake, such as high blood pressure. The Upper Limit (UL) is set at 2300 mg per day, meaning the guideline suggests not to exceed that amount. 

The average American consumes between 8 to 12g of table salt per day, which is 20-30 times more than the amount of sodium needed to replace everyday sodium losses from sweat, bowel movements, and urine. Table salt, also known as sodium chloride, is 40% sodium, so there are 3.2-4.8 grams of sodium in 8 to 12 g of salt. This excessive consumption of sodium, plus too little potassium, can lead to an increased risk of hypertension. 

However, these standard recommendations can be harmful to athletes, especially those who train outside and live in hot or humid climates.

So why is more sodium necessary for athletes?

Athletes need more sodium because it is lost while sweating. The amount of sodium excreted in sweat is large and depends on many factors, such as body mass, training level, temperature, clothing, gender, and heat/humidity acclimatization. 

Some athletes are also “salty sweaters”; if your workout clothes or hat and skin have white residue or streaks after training, it’s likely you are a salty sweater and lose more sodium than others. Typically, this applies to those who are untrained, at the beginning stages of heat acclimation, or men who generally lose more sweat. 

If you lose too much sweat while training and don’t properly replenish with electrolytes and fluid, you put yourself at risk for muscle cramps and poor recovery. Salt intake during intense training can also help prevent hyponatremia, or low sodium in the blood. 

Hyponatremia has become more prevalent in endurance events, especially ultra-endurance events or those who are on the course for longer periods of time. It is a potentially life-threatening condition that can cause fatigue, dehydration, swelling, nausea, vomiting, seizures, confusion, slurred speech, moderate to severe muscle cramps, and losing consciousness, possibly leading to death.

It tends to occur when sweating causes disproportionate sodium loss or an excessive intake of plain water, which dilutes the level of sodium in the blood. This is why it’s imperative to drink sports drinks containing electrolytes and not plain water for any physical activity over an hour.

So just how much sodium do you need for endurance events?

Athletes require more salt than the general population. Unless an athlete has a contraindication to increasing salt intake (like hypertension or kidney disease), most athletes should be liberal about consuming salt. 

Since sweat loss varies greatly from person to person, it’s difficult to determine an exact number that should be consumed. For instance, studies following football and tennis players found sodium losses ranging from 800 to 8,500 mg over two hours. Only a lab test can determine exactly how much sweat you are losing while training- but most athletes don’t have access to this. 

The baseline recommendation is 500-700 mg of sodium per hour but this increases upwards of 2000 mg + if you’re unconditioned, training in heat or humidity, a heavy or “salty sweater,” or exercising for several hours at a time. Athletes who fall into these categories need to be replenishing their fluid and electrolytes consistently in the days before, during, and after exercise.

What are some of the best ways for athletes to get in more sodium?

In order to avoid the downfalls of not getting enough sodium in and around workouts, it’s crucial to remember that the guidance of cutting back on salt for the general population doesn’t apply to athletes. Athletes regularly training over an hour need to replenish lost sodium, and reducing sodium intake is the last thing someone training for a marathon or Ironman should do. Here are a few general guidelines:

BEFORE TRAINING

Approximately 2-3 hours before training, consume 16-24 ounces of fluid, preferably water and a sports drink that contains sodium and other electrolytes. Choose a sports drink with at least 150 mg/sodium per 24 oz; if you can find one with more (upwards of 250 mg plus) that’s even better. If you are a salty sweater, be sure to include foods that also have sodium, either in your pre-workout meal or with sports foods. 

It’s always important to train with the nutrition you plan to race with, so experiment with how much fluid works and what types you like. Try different brands and assess how you feel in the first 10-15 minutes of your workout, halfway, and after your workout. If you felt sloshing, experienced cramping, or felt like you had to use the restroom the entire time, try a different brand.

30 minutes before your training, drink another 8 oz of fluid, either from a sports drink or water.

DURING TRAINING

If you’re doing an activity where you can eat more readily, such as biking, try to include foods such as pretzels, popcorn, or crackers to get enough sodium. These are also great to combat flavor fatigue from all the sweet-heavy sports foods. 

If you’re running and can’t fathom the thought of eating popcorn while running, stick to gels, chomps, jellybeans, and gus that contain sodium. Be sure to stay on top of your hydration with a sports drink that contains (you guessed it!) electrolytes. Aim to drink 4-6 ounces of water or a sports drink every 15-20 minutes. Start with at least 500 mg/sodium per hour of exercise and increase from there depending on your needs.

AFTER TRAINING

Sweat rates vary greatly and can range from as much as 1-4 lbs per hour. One way to help determine your sweat rate without having to go to a lab is to weigh yourself before and immediately after training. For every pound of weight lost during training, consume 16-24 ounces of water. If you lost close to 4 lbs, consider adding more fluid before and during your training.

What about eating more sodium through daily meals?

Increasing your sodium intake doesn’t necessarily mean you need to buy all of the most processed and sodium-laden foods available, such as frozen pizza, deli meat, frozen entrees, and heavily processed bread. 

Instead, think about adding salt while cooking and at the table to taste, especially if you live in a hot or humid climate. Eating foods that are saltier will help you stay hydrated and increase performance. Here are a few tips that will help you include more daily sodium to increase your performance:

  • Cook with salt and salt your foods at the table, especially if you live in a hot or humid climate.
  • Include foods such as crackers, salted potatoes, and pretzels to your training instead of regular sports foods.
  • Snack on salted foods like nuts, jerky, pickles, olives, popcorn, and chips.
  • Have chocolate milk post-workout since it contains more sodium than regular milk.

Replenishing lost sodium from training is crucial to maintaining performance, avoiding injury, and staying hydrated. However, you don’t need a fancy lab test to determine how much sodium is lost during training. 

If you follow these guidelines and experiment with what works, you should be able to avoid the pitfalls of sodium losses.

Adapted from the original post.
HEADER IMAGE: BOGDAN DREAVA

Marita Radloff, MS, RDN, CSSD, LD is a Board Certified Sports Dietitian teaching athletes how to fuel for their sport without restrictive diets. Marita believes everyone is an athlete, no matter the level of fitness. She strives to teach athletes how to fuel for performance, recovery, and endurance while still enjoying the foods they love without the confines of a diet. You can find and connect with her at Marita Radloff Nutrition.

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