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Electrolytes For Runners On A Keto Diet – What You Need To Know

If you are a runner, you are probably well aware of the need for proper hydration. Maybe you are one of those who carry a hip belt with a water bottle on their runs. If you are training for an ultra-marathon, you probably own a hydration vest or are at least thinking about getting one.

But what do you put into your hydration reservoir?

Don’t worry. I am not trying to convince you to swap your water for sugary sports drinks. Instead, we will look at some specific ingredients of those sports drinks: electrolytes.

What are they? Why are electrolytes essential for runners? And why might they be even more critical for runners on a ketogenic diet?

Let’s dive in.

What Are Electrolytes?

As you are undoubtedly aware, you sweat when you run. Usually more when it is hot and less when it is cold. And as any good runner, you take care of your body and replace that fluid loss with water.

However, when you sweat, you also lose minerals that play a vital role in your body.

These minerals are involved in every bodily process, such as digestion, brain function, and heart health. When you run low on them (pun intended 😉), you might experience symptoms such as cramps, side stitches, nausea, muscle weakness, or dizziness.

In the worst-case scenario, you risk hyponatremia – a dangerous condition where blood sodium is too low. Hyponatremia is a common problem in endurance training, likely caused by an overconsumption of plain water. That’s why it is essential to:

  1. avoid overhydration and drink only to thirst
  2. make sure to replace electrolytes and keep them in balance

While proper hydration is the topic for another article, let’s have a look at the minerals you should pay attention to and how they impact your body.


Many people argue that sodium might be the most important mineral in your body. If you fear eating too much of it because you are afraid that it will drive your blood pressure up, then I have good news for you.

First of all, there is no scientific evidence that reducing salt intake can prevent high blood pressure for most people. 

Secondly, if you are an endurance athlete, who regularly loses a decent amount of sodium through sweat, you need more salt.

And finally, if you are eating a ketogenic diet, you might need even more salt. Why? Because on a ketogenic diet, your kidneys naturally excrete more sodium. That is not a bad thing. But instead, it is a natural adaptation of your body while in a ketogenic state.

What Are The Symptom Of Sodium Deficiency And How Can You Get Enough?

Common symptoms of too little salt in your diet can include irritability and a lack of concentration, fatigue, and headaches.

Make sure to not artificially restrict your salt intake, salt your food according to taste and consider drinking a cup of bullion or so a day.

I had loved drinking hot bullion even before I went on a ketogenic diet – especially during the winter, and I still love it. I will add extra salt to my water when running in the heat, as I have found that it helps with fatigue and prevents headaches.


Potassium is maybe one of the hardest minerals to get enough of on a very low carbohydrate diet. However, most people are not meeting the recommended intake for potassium, , so this is not an issue caused by a ketogenic diet.

It is better to get your potassium from whole food sources than fill your needs with a supplement.

You can overdose potassium from supplements with symptoms ranging from nausea to vomiting and even cardiac arrest. However, overdosing on potassium from foods is exceedingly rare unless you have a serious medical condition.

What Are The Symptom Of Potassium Deficiency And How Can You Get Enough?

Common symptoms of a potassium deficiency include muscle cramps and twitching. You may also experience fatigue, headaches, constipation, or heart palpitations.

The best potassium sources on a ketogenic diet include avocados, brussels sprouts, spinach, and fatty fish. Include potassium-rich foods in your diet and a general electrolyte supplement geared towards endurance athletes or keto dieters, as needed. But make sure to avoid the “more is better” trap for supplementation.


Like potassium, magnesium is a nutrient of concern for many people – not only keto dieters.

Magnesium is critical for many processes, such as protein synthesis, brain biochemistry, nerve transmission, and muscular contractions.

What Are The Symptom Of Magnesium Deficiency And How Can You Get Enough?

Magnesium deficiencies can result in muscle cramping or twitching and have been linked to symptoms of depression and anxiety. Frequent headaches might also be a sign of a magnesium deficiency.

The best magnesium sources on a ketogenic diet include nuts and seeds, leafy greens, avocados, and fatty fish.

You can also supplement with magnesium. However, be aware that there are several different forms of magnesium, and some can cause digestive upset.

If you choose to supplement, opt for magnesium glycinate, magnesium citrate, and magnesium chloride, as the body best absorbs these forms. As always, it is best to meet your daily needs through diet and to consult your doctor before supplementing.


Calcium is one of the most abundant minerals in the body. It makes your bones and teeth strong and plays a vital role in regulating nerve function, ensuring proper muscle contraction and blood clotting.

What Are The Symptom Of Calcium Deficiency And How Can You Get Enough?

If you are deficient in calcium, you may experience brittle fingernails, lethargy, poor appetite, and tingling fingers.

However, people following a ketogenic diet usually get enough calcium through cheese and other dairy products.

If you choose not to eat dairy products, you should eat small fish, including their bones, leafy greens, almonds, or pumpkin seeds, to meet your calcium needs.

How Does A Ketogenic Diet Affect Your Electrolyte Levels?

When you first switch to a ketogenic diet, you may experience the dreaded “keto flu.” While it is not a severe disease and you are not contagious, you might experience the following symptoms:

  • brain fog 
  • irritability
  • headache
  • sugar cravings

These symptoms occur because your body is going through a substantial metabolic shift that results in fluid and electrolyte balance changes.

Once you reduce your carbohydrate intake to very low levels, your body naturally decreases its glycogen stores.

Glycogen is the storage form of sugar found in your muscles and liver. Alongside glycogen, your body stores water. That is why many people who start a low-carb diet lose more significant amounts of body weight in the beginning. They deplete their muscle glycogen and, along with it, lose water weight.

And as water and electrolytes are linked in your body, you will also lose a more significant amount of essential minerals at the start of your keto journey. 

Hence, your electrolyte needs may be significantly higher when you are a runner and training frequently while also switching over to a ketogenic diet.

You can lessen the keto flu symptoms or avoid it altogether by adding electrolytes.

In addition to taking electrolytes during your runs or races, you might benefit from adding electrolytes to your drinking water or other beverage of choice. If and how many additional electrolytes you might need depends on many factors. You need to consider your eating habits, exercise levels, climate, and if you already have some underlying deficiency.

It may be that you need more of one mineral or that you don’t need to supplement with electrolytes at all outside of your exercise sessions. You must check-in with yourself regularly and adapt your electrolyte intake according to your needs. 

Final Words

As stated already, always try to meet your needs through food first and consult your doctor before supplementing.

Micronutrient needs vary from person to person.

For example, suppose you are a marathon runner who trains several hours per week on top of having a stressful corporate job and a busy family life. In that case, your needs are likely to be very different from an 83-year-old who spends their day reading a good book 😉.

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