Hydration has become a popular word, but it’s hard for a company to make a product stand out by selling plain water. So, companies are now selling you electrolytes in your water (or electrolyte packs to add to your water). A lot of people are buying these products even though many couldn’t even tell you what an electrolyte is. It’s kind of like when shampoos were advertising they were pH balanced. The average person may have heard of pH but most had no idea what the “balance” was.
At one time, Gatorade and a few similar products dominated the electrolyte drink market. These drinks were promoted mostly for people playing sports or exercising in the heat. Now, electrolyte drinks, as well as electrolyte powder that can be added to water, are advertised to a wide audience. Despite this, many medical websites say that under most conditions, most people don’t need these products. Even so, some of you may be thinking” “I don’t care what these sites say; I want electrolytes in my water every day.” If you think that, consider the following.
Five days a week, I get a news email from a group called NutraIngredients. This is a little like a Wall Street Journal for the nutrition and supplement industries. NutraIngredients seems to try to relate most news honestly. However, since they solicit product ads, this organization doesn’t seem to want to classify products as ineffective as often as they could. Yet, their recent article on electrolyte products politely pointed out that they may not help everybody. So, the question is: Can they help anybody? Before addressing that, let me first define electrolytes.
What are electrolytes? They are ionic (charged) atoms or molecules that contribute substantially to the positive or negative charges of body fluids. Note the word substantially. Something like iron can hold positive charge, but not enough roams free to make much dent on fluid charges.
Electrolytes provide the right conditions for critical life processes to work (like nerve impulses and muscle contraction including heart muscle). People can die from electrolyte depletion.
The largest contributors to body fluid charges are sodium (+), chloride (-), and potassium (+). These 3 ionic atoms form the basis for electrolyte drinks. Companies also add other electrolytes, sugar and/or other carbohydrate, and sometimes vitamins.
Electrolyte drinks have two possible benefits:
1. Electrolytes in the drink might replace electrolyte losses. This provides safety and improves
exertion performance.
2. Compared to just water, electrolytes drinks may increase the % water entering the blood from
the digestive system (due to the electrolytes and sugar if the contents are not too high)
As a side note, in some circumstances, the added sugar in electrolyte drinks can provide energy fuel during prolonged exertion, However, that topic is not covered in this writing (though it is discussed in another writing on this blog).
Electrolyte drinks for replacing lost electrolytes. Most people don’t need electrolyte drinks to get enough sodium or chloride in normal circumstances. It is true that sweat takes sodium out of the body, but sweating has to be long and strong to start depleting most people’s sodium. Even then, people that eat a lot of processed foods and salt their foods may still be fine.
Nonetheless, for those people and others, if sweating occurs profusely for a long time, it’s good to get a little extra salt before or during the activity. Having an electrolyte drink during the extended sweating can provide a convenient way to replace some of the lost sodium. This can especially hold for those who lose sodium easily (which can be detected by noticing dried salt on skin or clothes).
Usually, even lengthy sweating doesn’t deplete potassium enough to cause a dangerous shortfall (even for the many people who eat less than optimal amounts of this mineral). Nonetheless, with very extreme perspiration, potassium can deplete. Eating good amounts of this mineral + having some in an electrolyte drink can help. How much potassium to eat is an involved topic that goes beyond the current writing.
Some of you are now thinking: “Wait a minute. I had a sports coach who told us to eat bananas before long competitions to get potassium to prevent cramps.” Well, during prolonged muscle exertion, something does happen with this mineral which is independent of sweat losses. Repeated muscle contraction moves potassium out of the muscle temporarily. The percent of muscle potassium that leaves, and how fast it goes back, could affect exercise performance and cramping tendencies. Consuming a good amount of potassium could minimize the percent that leaves and speed up the return. However, very little real research exists about potassium intake in this regard. And, even if short term potassium intake could help, it’s unknown whether the amount of potassium in electrolyte drinks can have a big effect.
Other situations where electrolyte replenishment may help. I just said that usually electrolyte drinks have only a narrow use for replenishing sodium and chloride. On the other hand, unusually large water losses due to vomiting, diarrhea, or diuretic drug use can deplete these minerals as well as potassium. In these cases, you may benefit from specific electrolyte drinks. These include products like Pedialyte (which can be taken by both children and adults). If these situations become severe, professional health care should be sought. Sometimes, intravenous water + electrolytes offer the best initial treatment.
Calcium and magnesium. Some electrolyte products contain calcium and magnesium. One study (1) reports that calcium sweat losses after running over 6 miles is only 20 mg. Recommended daily calcium intakes equal or exceed 1000 mg. Thus, sweat losses of calcium are not usually going to dent body stores. Nonetheless, some studies say that short-term small calcium loss can trigger a hormone reaction that draws calcium out of the bone. However, other studies say this does not happen. For the moment, I don’t have this on my worry list.
Magnesium acts as an electrolyte, though it functions mainly in other ways. Serum magnesium drops right after strenuous exercise, though this is thought to mostly reflect body redistribution rather than loss. Even so, some magnesium is lost in sweat and urine during exercise. It has been proposed that regular exercise can increase magnesium needs by 10-20% (2). To compensate for this, dietary magnesium intake may be more important than what’s in an electrolyte drink. Still, the drink may make some contribution. Magnesium nutrition is a whole separate subject (which I discuss elsewhere in this blog).
Do electrolytes improve water hydration efficiency? A number of studies show that this can happen even when people are in non-exertion, room temperature conditions. However, how much, if any, improvement occurs in these studies depends on:
• How the water uptake is measured
• Individual people’s make up (a lot variation has been seen)
• The contents of the electrolyte drink.
The last consideration includes sugar content. At low levels, sugar can combine with electrolytes to help with the speed and efficiency of water uptake into the blood. This is in addition to the possibility that sugar + flavoring can help a person want to drink more liquid.
Does any of this matter in a practical sense? Many medical websites say that most of the time, the answer is no. It is true that that for reaching an ideal hydration state, an electrolyte drink can do it with a little less liquid versus plain water. But, who can figure out when they hit that state? There is no magic number of glasses of water and/or electrolyte drinks per day that works for everyone. This depends on the person’s make up, the person’s activities, and how much water they get from foods and all beverages. It seems reasonable to just encourage people to drink a little more than needed to not feel thirsty (thirst is a good internal guide when one is not rapidly losing a lot of water). Another crude test is to look for light yellow or colorless urine rather than a dark yellow. For normal conditions, I don’t know of any study that shows practical health benefits of electrolyte drinks giving modest improvements in water uptake efficiency.
On the other hand, for situations of heavy sweat for a sustained period, an electrolyte drink can replenish body water faster with less total liquid than plain water (which would produce less bloating). An approximate idea of when one reaches this state can be gained by looking at urine color and weighing oneself. However, both methods are not always practical during training or competition (though they can be done afterwards to plan future hydration strategies).
The salt in electrolyte drinks can sometimes make a person more thirsty. That can make it hard to hit just the optimal intake without going over it. Still, electrolyte drinks do provide a convenient way to hydrate and replace salt during long bouts of training or sports competition. Specific hydration protocol recommendations I have seen don’t exactly match each other, but here’s one from a YMCA: https://www.glcymca.org/hydration/.
Can electrolyte drinks overload you on electrolytes? Yes, this can happen. Drinking lots of these drinks regularly can elevate total sodium intake. This can present problems for people needing to restrict total sodium intake (though that’s not as big a group as is often thought).
Another issue arises when getting a lot of electrolytes quickly from sports drinks without any food to slow absorption. This could throw off electrolyte balance, which could cause symptoms ranging from uncomfortable to dangerous. The dangerous state probably doesn’t happen all that often, but it is still a concern that should be considered.
My conclusions. Based on current data, I don’t see value for general use of electrolytes in water. However, during perfuse & prolonged sweating, electrolyte drinks provide a convenient way to replace electrolytes + raise water uptake efficiency. For other extreme water loss states, products like Pedialyte can be useful (though these states can call for visiting a health care facility).
1. Wenk C, Kuhnt M, Kunz P, Steiner G. [Methodological studies of the estimation of loss of sodium, potassium,calcium and magnesium through the skin during a 10 km run]. Zeitschrift Fur Ernahrungswissenschaft, 1993;32:301–307.
2. Nielsen FH, Lukaski HC. Update on the relationship between magnesium and exercise. Magnesium Research 2006;19:180–189.