What are Electrolytes?
Electrolytes are similar to laundry soap in your washing machine; although soap doesn’t make your washer run, it is necessary to get your clothes clean.
Like laundry soap, balanced electrolytes are necessary for your digestive, cardiac, muscular and nervous systems to function well.
Electrolytes are sodium (Na+), potassium (K+), calcium (Ca 2+), magnesium, (Mg 2+), chloride (Cl-), phosphate (PO4 2-), bicarbonate (HCO3-), and sulfate (SO4 2-).
Sodium, potassium, magnesium and calcium are the four major electrolytes that maintain the body’s fluid balance.
As a side note, the + and – symbols mean these minerals are ionic. Their ionic nature gives the electrolytes the ability to carry electrical energy to keep the body’s systems functioning.
Why is Electrolyte Balance Important for Runners?
For a runner, keeping your electrolytes balanced is key for successful training and optimum performance.
If your electrolytes are imbalanced, you could potentially compromise the success of your next run because of muscle fatigue or cramping.
Moreover, drinking water alone isn’t enough.
If you are trying to rehydrate by drinking a lot of water, failing to consume electrolytes at the same time can upset the balance of electrolytes in your bloodstream.
In a worst-case scenario—drinking lots of water during a very long race in the heat, for example—this can even lead to a dangerous condition called hyponatremia, where blood sodium levels drop too low.
Therefore, keeping your electrolytes balanced is critical for both performance and health.
Along with the more frequent muscle cramps in the legs, stomach cramps or side stitches can also be the result of an electrolyte imbalance.
But wait, there’s more:
Other electrolyte imbalance symptoms are: muscle spasms, dizziness, fatigue, nausea, constipation, dark urine, decreased urine output, dry mouth and foul breath, dry skin, muscle weakness or stiff and achy joints.
Electrolyte Balance and Cramping in Runners
While running you lose electrolytes through your sweat, mainly sodium and potassium.
Potassium permits the movement of fluids and nutrients across your cells’ membranes, thus allowing them to carry on their metabolic activities such as contacting muscles.
Without sufficient potassium, your muscles cells can’t generate the necessary nerve impulses that control muscle contraction.
Cramping is the body’s way of letting you know the electrolyte tank is empty and it cannot continue; it’s like a car running out of gas.
Even you’ve never experienced cramping, electrolytes need to be replenished after sessions longer than a hour to facilitate optimal recovery.
Electrolytes and Running Performance
Even in more mundane situations, when not racing in extreme heat, maintaining your electrolyte balance has its advantages.
A 2001 study by Sanders, Noakes, and Dennis found that cyclists who consumed a sports drink with sodium in it during a 4.5 hour ride produced much less urine than those who consumed an equivalent volume of salt-free sports drink.
They concluded that this was because the cyclists did not need to excrete as much water to balance out the sodium concentration inside their bodies.
This bodes well for marathoners—after all, who wants to have to take a bathroom break during a race?
It seems strange that the “saltiness” of a fluid influences how much urine your body will produce, but when the fluid you’re drinking (the sports drink) is closer in electrolyte concentration to the fluid you’re losing (sweat), your body can more or less replace the sweat one to one instead of having to add in electrolytes that are already in your body, resulting in lower overall sodium levels in your blood.
The Best Way To Replace Electrolytes
Now that we understand the function and importance of replenishing your electrolytes, we can discuss the best possible options to replenish quickly and efficiently.
Of course, you can always opt for electrolyte drinks like Gatorade and Powerade, but those often contain high amounts of simple sugar.
When you’re replenishing electrolytes throughout the day, you don’t want to be consuming high amounts of simple and artificial sugars.
Moreover, according to researches like Noakes, most sports beverages don’t contain nearly enough sodium to replenish what a runner needs.
That is why we recommend using a product specifically designed for endurance athletes like LMNT Recharge.
Specialized products like LMNT recharge have higher amounts of sodium to specifically meet the demands of runners. Plus, they don’t contain sugar, making them much healthier overall.
If you want to give them a try, they have a special offer where you can get an 8 pack sample for free. Check it out here.
For Sodium, can I just add more salt to my food?
Just because sodium is an electrolyte, don’t assume your daily sodium consumption will replenish your electrolyte loss from your run.
First, sodium causes water retention. Consuming sodium alone and not in combination with other electrolytes may cause severe swelling of the hands, feet and ankles.
Second, the body monitors electrolyte losses during the run through hormones.
After a run, if sodium is consumed in high amounts without other electrolytes to balance, it neutralizes the hormonal system and disrupts the bodies regulation processes.
Sodium should be consumed in combination with other electrolytes to assist proper electrolyte balance.
How to Calculate Your Exact Electrolyte Needs
Knowing what we know now about the latest research on hydration, dehydration, and performance, how should you structure your own hydration routine, and what’s the best way to figure out how much you need to drink?
Does Weighing Yourself Before and After a Run Measure Hydration Loss?
One of the most popular ways of measuring your water needs is by weighing yourself before and after you run, then calculating the difference.
It seems fairly basic: if you go out for a run in the heat, you sweat out a lot of water and need to replace it.
But, there’s more to it than that. In fact, scientific research has shown that there are a few problems with this model.
First, this doesn’t measure your electrolyte levels.
Second, not all of the weight you’re losing is water!
A significant portion is fuel—carbs and fat, burned for energy during the course of your run.
The exact caloric cost of running varies from person to person, but:
- A figure of 120 calories per mile is about right for most runners.
- So, for example, over the course of an eight or nine-mile run, you’d expect to burn about 1000 calories.
- If you are running at an easy pace, about half of these calories will come from carbs, and the other half will come from fat.
- After doing some math on the energy content of carbs and fat, you’ll find out that you’ll be losing almost half a pound of fuel during your run.
- On top of this, a wide body of research has established that your body stores water alongside glycogen, the molecule carbohydrates are converted into for storage.
In one representative study by Karl-Erik Olsson and Bengt Saltin at the Karolinska Institutet in Sweden, 19 healthy subjects had their total body water and muscle glycogen content measured before and after a three-day period during which they consumed only fat and protein, depleting their body’s carbohydrate stores.
Following this, the subjects ate a carb-rich diet again for four days and the measurements were taken again.
Olsson and Saltin demonstrated a fluctuation in body water content according to the concentration of glycogen stored in the muscles, to the tune of three to four grams of water per gram of carbohydrate.
For a runner, this means that each gram of carbohydrates that you burn liberates a few grams of water which can help maintain your hydration level, even though you’re losing water to sweat.
What About Drinking to Thirst?
Timothy Noakes, a South African exercise physiologist and medical doctor, has demonstrated in several studies that athletes can lose at least 2.2 pounds of weight during exercise, and possibly up to 4.4 pounds, without any measurable decrease in hydration.
Additionally, Noakes points out that runners seem to have differing levels of sensitivity to water loss.
Some become extremely thirsty after only a pound or two of body weight lost, while others lose up to 8% of their body weight during a race, even when they’re drinking water en route!
Some multi-hour ultramarathon events feature weight checks at intermediate points along the course, but primarily to prevent overhydation in the form of hyponatremia, a dangerous condition that results from drinking too much water or sports drink.
What About Monitoring the Color of Your Urine?
Unfortunately, that too fails to pass scientific muster.
A 1999 study by three researchers at Maastricht University in the Netherlands compared the color and volume of urine production in eight trained cyclists before and after a long cycling session in the heat which led to a 3% loss in body weight.
While it is true that urine color and output followed the trends we’d expect—a small amount of dark yellow urine immediately after exercise, then increasingly clear urine and larger volumes produced as the subjects rehydrated—neither the color of the urine nor its volume were statistically correlated with the amount of water in the body.
In fact, the only scientifically valid measurement of hydration is the concentration of your blood plasma, which is not exactly easy to measure.
So, How Can We Accurately Measure Hydration and Electrolyte Loss?
So what’s a runner to do?
Well, luckily for you we’ve developed a calculation that factors in your carbohydrate and fat burned while also compensating for glycogen storage and actual sweat loss.
Download Your Hydration Calculator!
Find out your sweat rate and how much you need to drink after a run based off temperature conditions
Or, if you want to do it yourself, here are the steps to take:
Step 1: Calculate your total calories burned. 120 calories per mile is about right for most runners.
Step 2: Calculate percentage of calories burned from fat and carbohydrates. This is a reflection of intensity. This is a relatively complicated calculation, but if you want the in-depth details check out the article we did on this earlier here.
Step 3: This will give you how many grams of carbs and fat you burned.
Step 4: Measure how much actual weight you lost
Step 5: You can now subtract the value from how many grams of carbs and fats you burned from total weight loss. The difference is how much sweat you lost.
