Beyond Water & Carbs • No Limits

The Role of Electrolytes in Athletic Performance

You begin your run on a hot day, as the sun feels like it’s peeling layers of skin from your body. You’ve barely even made it through the warm-up, and you are already sweating through your clothes. By the time you are halfway through the session, you feel the salt on your skin. You feel a little dizzy, and you notice you feel much more tired than you typically do.

You start to triage the situation: you’re taking in enough calories. You’re drinking enough water, in line with your sweat rate. Then you realize: electrolytes! I forgot my electrolytes. Carbohydrates have received so much attention in the fueling and hydration news that it may be easy to forget those tiny charged particles that are equally important to our success.

Electrolytes play a crucial role in our bodies for everyday health, as well as optimal athletic performance. This week, we’ll review what electrolytes are, why they matter, and how to recognize imbalances.

What Are Electrolytes?

Electrolytes are minerals that carry an electric charge, found in your blood, sweat, and urine. They include sodium, potassium, calcium, magnesium, chloride, bicarbonate, and phosphate. These tiny charged particles play a significant role in the real-world function of our bodies, especially for endurance athletes.

For endurance athletes, electrolytes are vital for several key functions.

1. Muscle function

Electrolytes like calcium and magnesium enable proper muscle contraction and relaxation. Calcium is crucial for initiating muscle contractions, while magnesium helps muscles relax. Potassium also plays a role in muscle function by regulating muscle cell excitability [2].

For example, during a hard effort, calcium ions trigger the fibers of your leg muscles, causing them to contract powerfully. After the sprint, magnesium helps your muscles relax by competing with calcium for binding sites. Potassium helps maintain the right electrical charge across muscle cell membranes, ensuring they’re ready for the next contraction.

2. Hydration

Sodium helps maintain fluid balance through osmosis, preventing dehydration. It’s the primary electrolyte lost in sweat, with losses ranging from 460-1840 mg per liter of sweat[2]. Proper sodium balance is crucial for maintaining blood volume and preventing hyponatremia during prolonged exercise[1].

For example, while running a marathon on a hot day, let’s say you lose 1 liter of sweat per hour (your individual sweat rate will be unique). And let’s say this sweat contains approximately 1000 mg of sodium. If you only drink water without replacing sodium, your blood sodium concentration will drop, potentially leading to hyponatremia. Proper sodium intake helps maintain blood volume and prevents this dangerous condition.

3. Nerve signaling

Electrolytes facilitate the transmission of electrical impulses along nerve cells. This is essential for muscle coordination and overall nervous system function during endurance activities.

For example, the rapid and coordinated movement of your legs during cycling requires constant communication between your brain and muscles. Electrolytes like sodium and potassium facilitate the transmission of these nerve impulses, allowing for smooth pedaling and balance maintenance.

4. pH balance

Electrolytes help maintain the proper acid-base balance in your body. This is particularly important during intense exercise when lactic acid buildup can alter blood pH levels.

For example, during a high-intensity interval training session, lactic acid builds up in your muscles, potentially lowering your blood pH. Electrolytes like bicarbonate act as buffers, helping to neutralize this acid and maintain a stable pH, allowing you to continue exercising at a high intensity.

5. Carbohydrate absorption

Sodium plays a crucial role in carbohydrate absorption in the intestines. Think of sodium and glucose (carbs in your bloodstream) as a buddy system for getting energy into the cells of your working muscles. Your body needs to move nutrients once they are digested by the intestines into the bloodstream so they can be used for energy.

Now, think of sodium as a helpful friend to glucose, which is a key source of energy, especially during endurance events. But glucose can’t easily get into your cells on its own. This is where sodium comes in. There’s a special “doorway” in the walls of your intestines called the sodium-glucose cotransporter (SGLT1). This doorway is designed to let both sodium and glucose through at the same time. Sodium is the key to not only opening the door but walking through it and into your bloodstream. And, it brings glucose along with it.

By having sodium in your sports drinks or energy gels, you’re not just replacing electrolytes lost through sweat – you’re also helping your body absorb the carbohydrates you need for energy more efficiently. This can help you maintain your performance during endurance events.

6. Cardiovascular function

Electrolytes, particularly sodium and potassium, are essential for maintaining proper heart function. They help regulate heart rate and blood pressure, which is critical during prolonged endurance activities [3].

For example, during an endurance swim, your heart rate increases to meet the demands of your muscles. Sodium and potassium work together to regulate your heart’s electrical activity, ensuring a steady, efficient heartbeat. This allows for consistent blood flow and oxygen delivery to your working muscles throughout the swim.

7. Thermoregulation

Electrolytes contribute to the body’s ability to regulate temperature through sweating. Proper electrolyte balance helps maintain efficient sweating mechanisms, crucial for endurance athletes competing in hot conditions [1].

During intense exercise, especially in hot conditions, athletes lose electrolytes through sweat. Replenishing these is crucial for maintaining performance and preventing health issues.

Signs of Low Electrolytes

Watch out for these symptoms of electrolyte depletion:

Muscle cramps*
Dizziness
Irregular heartbeat
Belly bloating
Mental confusion or brain fog
Fatigue
Nausea
Headaches

*It’s important to note that not all muscle cramps are due to low electrolytes. If you have a single site cramping, that may be more from muscular fatigue than an electrolyte imbalance. That being said, if you experience muscle cramps, the research has demonstrated that putting salt directly on your tongue can be effective for releasing the cramp.

Signs of Excess Electrolytes

While less common, having too many electrolytes can also be problematic. Symptoms may include:

Fatigue
Muscle weakness
Nausea and vomiting
Swelling and bloating in the fingers and ankles/feet
Frequent urination
Confusion or irritability
Seizures
Irregular heartbeat
High blood pressure

It’s important to note that electrolyte imbalances in either direction can be serious and may require medical attention.

Maintaining Electrolyte Balance

For most people, a balanced diet and proper hydration are sufficient to maintain electrolyte levels. However, endurance athletes need to pay special attention to their electrolyte intake, especially during long or intense training sessions or competitions.

To determine your unique needs, it’s best to consult with your coach. If you’ve been struggling to determine your needs, you may consider a sweat rate assessment. Our partner Precision Hydration has testing centers across the US. To find out if they have a center near you, click here.

At-home remedies you can try include the Gatorade patches, Nix Biosensors, or Hdrop systems. However, the accuracy of these patches and systems remains in question. Levelen offers a sweat test you can do at home and mail in.

It’s also important to keep track of your precise electrolyte and fluid intake during training. Then, log how you felt to get a sense of your water and electrolyte needs across varying conditions. It is helpful to report on weather conditions in this case, so you have a record of what works (or doesn’t) in varying weather.

Research Findings on Hydration and Performance

Recent studies have provided valuable insights into hydration strategies for athletes. Here’s a sampling. See the citations if you want to read more.

Sweat rates: Research has shown that sweat rates can range up to 3.5 liters/hour in trained athletes and even greater (up to 8.8 liters/hour) if wearing protective clothing [2].
Electrolyte loss: In 1 liter of sweat, athletes can lose 460-1840 mg of sodium, 710-2840 mg of chloride, 160-390 mg of potassium, 0-36 mg of magnesium, and 0-120 mg of calcium [2].
Hydration recommendations: The American College of Sports Medicine recommends that athletes aim to consume a fluid volume equal to the amount lost through sweat during exercise, which is typically 0.4 to 1.8 L/hour[3].
Individual variability: Studies have highlighted the importance of individualized hydration strategies, as sweat rates and electrolyte concentrations can vary significantly between athletes[1].

By understanding electrolytes and recognizing the signs of imbalance, athletes can take proactive steps to maintain their health and performance. Stay hydrated, stay balanced, and keep pushing your limits safely!

Ready to dial in your hydration and electrolyte strategy? Don’t leave your performance to chance—work with a No Limits Endurance Coach to create a personalized fueling and hydration plan tailored to your training and racing needs. 💧💪 Book your FREE consult today and take the guesswork out of your electrolytes. Your peak performance starts with the right foundation!