Electrolyte supplements are extremely popular right now in the fitness space. There are a ton of claims around their reported benefits, which revolve around improved hydration and physical performance.
Similar to most dietary supplements, the answer to whether or not they’re beneficial is very nuanced and depends on a number of different variables.
What we want to address in this article is whether or not electrolyte supplements are useful in the context of resistance training specifically, and if you should consider taking them.
What Are Electrolytes and Why are they Important?
Electrolytes are specific minerals that contain an electrical charge when dissolved in water that can be obtained from both food and beverages. Sodium, potassium, magnesium, chloride, and phosphate are some of the main electrolytes that our bodies need to function properly.
They are important for a variety of physiological functions, including regulating fluid balance, maintaining proper nerve and muscle function, and supporting other metabolic processes. For example, magnesium is involved in more than 300 different metabolic processes including ATP production, protein synthesis, proper muscle and nerve function, and many more.
In other words, electrolytes are really important for our bodies to function correctly.
When we exercise, we lose water and electrolytes through sweat. The quantity of electrolytes and water lost in sweat is dependent on different variables like the temperature of the environment, the intensity and duration of the exercise, as well as the individual person’s propensity to sweat. For example, some people are naturally light sweaters while others are heavy sweaters. Also, some people naturally excrete more electrolytes (AKA salty sweaters) than others.
If you’re exercising for prolonged periods of time without replenishing the fluid you lose through sweating, you’re going to become dehydrated, which can negatively influence exercise performance [1]. In fact, there’s evidence to show that poor hydration can negatively affect many different aspects of your fitness. For example, a 2007 review article suggests that hypohydration (ie: being poorly hydrated) can reduce strength by ~2%, power by ~3% and high-intensity endurance by ~10%, which shows that poor hydration doesn’t only affect cardiovascular performance, but also strength and power [2].
Since electrolytes play an important role in fluid balance, muscle contraction, and hydration, they’ve become a very popular sports supplement.
Companies that sell electrolyte products claim that electrolyte supplements can:
- Improve hydration
- Improve performance
- Speed up recovery
- Reduce cramping
While the thought process behind the use of electrolyte supplements makes logical sense, many supplement companies suggest that they’re beneficial for everyone in every context, which is not true. While in some contexts, electrolyte supplementation can help, they’re definitely not going to provide a performance boost in all contexts.
Let’s go ahead and dive into some research on the effects of electrolytes on exercise performance to get a better picture of why or why not electrolytes may be beneficial for you.
One important thing to keep in mind is that the research on electrolyte supplementation is done exclusively on endurance training and not resistance training. This is because endurance exercises, like long-distance running, typically induce more dehydration than resistance training. Also, most research on exercise in general is conducted using aerobic exercise and the body of literature on resistance training just isn’t there yet.
Effects of electrolyte supplementation on hydration status
Of course, what we want to see is that using electrolytes helps you hydrate quicker and more effectively than water; if not, then there’s no point in using them if simply drinking water is equally as effective. Thankfully, there are plenty of studies comparing the effects of electrolyte supplements and water on hydration status.
A really interesting study published in 2021 compared the effects of water, versus electrolytes + water, versus electrolytes + water + carbohydrate on hydration status using the beverage hydration index (BHI) [3]. BHI is an index used to compare the hydration properties of different beverages compared to water as a control. The reason that the researchers included a group of individuals that supplemented with electrolytes plus carbohydrates is the fact that simple carbohydrates actually aid in hydration by essentially enhancing your cells’ ability to absorb water. Both the electrolyte-only and electrolyte + carbohydrate supplements contained the same concentration of sodium and potassium, however, the carbohydrate + electrolyte drink also contained simple carbohydrates. The participants all consumed their corresponding supplement in the morning in a euhydrated state (AKA properly hydrated), and urine was collected in 60-minute intervals for a total of 4 hours to assess hydration status.
The results indicated that although electrolytes alone increased BHI scores by a higher value than water alone, they were not statistically significant. On the other hand, the addition of carbohydrates on top of the electrolytes did have a significantly positive effect on BHI scores, suggesting that carbohydrates + electrolytes can be more hydrating than simply drinking water alone, which isn’t really a surprise. This study indicates that supplements that include electrolytes alone and do not include carbohydrates may not be the most efficient way to rehydrate and if you sweat a ton during exercise, consuming some simple carbohydrates alongside your electrolytes can be beneficial.
There is one big limitation to this study though, and it’s the fact that the participants were not dehydrated when consuming their respective drinks. In fact, the researchers made sure that everyone was properly hydrated to standardize the hydration status of the participants. There’s really no reason to think that these drinks would work differently if participants were dehydrated, but perhaps the magnitude of the effect might be different. For example, electrolytes alone may be slightly more beneficial than water when starting off from a dehydrated state.
That being said, there is research investigating the effects of different beverages on hydration status in individuals who are dehydrated from exercise. A 2020 clinical trial compared the effects of an oral rehydration solution (ORS) with a high electrolyte concentration versus a sports drink versus just water on fluid balance in cyclists [4]. And ORS is essentially a solution of carbohydrates and electrolytes, but it’s typically at a higher concentration than a sports drink like Gatorade. Pedialyte is an example of a commonly consumed ORS. The participants consumed their respective beverages both during and after exercise with a volume amounting to 150% of sweat lost during the exercise protocol. The results showed that the ORS significantly increased fluid retention compared to the sports drink and water, indicating that it may be a better choice for rehydrating after exercise.
With regard to hydration specifically, it seems like electrolyte supplements that do not contain carbohydrates are not nearly as effective as carbohydrate-containing beverages to improve hydration, which is why most sports drinks contain some sugar in addition to electrolytes. That being said, another important variable to consider is the concentration of both carbohydrates and electrolytes in the drink.
Concentration refers to the amount of solute (carbohydrates and electrolytes) per unit of volume in solution (water). For example, you can measure concentration by saying there is 2 grams of sodium per 16 oz of water, which would be a concentration of 1g of sodium per 8 oz. Hydration beverages can obviously contain different concentrations of electrolytes depending on how much water is used to dilute them. Hydration beverages can be categorized into three main categories based on their concentrations, hyper-, Iso-, and hypo-tonic. Hypertonic drink are those that contain a higher concentration of solutes than the fluids in your body. Isotonic drinks have a similar concentration and hypotonic drinks contain a lower concentration of solutes compared to the fluids in your blood. For example, classic Gatorade is an example of an isotonic hydration drink because it contains a concentration of electrolytes and carbs than your bodily fluids.
You might be thinking, why are we talking about the concentration of electrolyte beverages? Isn’t the quantity of electrolytes in my drink what matters?
In other words, isn't drinking a gram of sodium more important than how much water I put my sodium in??
And the answer to that question is no.
The concentration of electrolytes and carbs in the beverage is likely the most important variable influencing the hydrating effects of the beverage.
Beverages that contain both carbohydrates and electrolytes and are hypotonic (have a lower concentration of solutes) seem to be superior for hydration.
A really great meta-analysis published in 2022 actually compared the hydrating effects of electrolyte-containing beverages with and without carbohydrates on hydration at different concentrations during continuous exercise [5]. In other words, they compared the effects of hyper-, Iso-, and hypo-tonic electrolyte drink without carbohydrates and hyper-, Iso-, and hypo-tonic electrolyte drink with carbohydrates on hydration during continuous exercise. Essentially what they found was that drinks with lower concentrations of electrolytes and carbs were more beneficial for hydration than those without carbs and with higher concentrations. Hypotonic beverages containing both electrolytes and carbs were significantly more hydrating that just drinking water as well.
This might sound confusing. If electrolytes help with hydration, why would a lower concentration be better?
Let's explain this in the simplest way possible. The term hydration essentially means that the cells of different tissues in our body have sufficient water. The way they get that water is from our blood. When we drink fluids, they are absorbed into our bloodstream. Those fluids contain water plus anything else in it (e.g., electrolytes, carbs, etc.,). The water from those fluids then moves from our blood stream into different cells and tissues to help hydrate them. Water can also move in the opposite direction from our cells into our blood as well. The movement of water in and out of our blood vessels and tissues is regulated by a process called osmosis. Osmosis refers to the movement of water from an area of higher water concentration (low solute concentration) to an area of lower water concentration (high solute concentration). If the concentration of water is higher in your bloodstream, then it’s going to move into your tissues to reach equilibrium, and vice versa.
If this sounds confusing just use the image below to paint a better mental picture. You see that there’s just water on the left and then water plus sucrose (sugar) on the right. The “outer wall” of your cells are “partially permeable membranes.” They are partially permeable because some things can pass through them, like water, while others cannot, like large sugar molecules. Let’s think of the left side as your bloodstream, and the right side as muscle cells. Since there is more water in your bloodstream than in your muscle cells, water will move from the blood into the muscle cells. It’s that simple.
This is where the concentration of your electrolyte beverage comes in. Since hypotonic drinks have a lower concentration of solutes (e.g., carbohydrates and electrolytes) than your blood, it actually “dilutes” your blood causing it to have a higher concentration of water. Since hypotonic drinks increase the amount of water in your blood, it’s going to cause water to move from your bloodstream into different tissues, which is why it is superior for hydration than iso or even hypertonic solutions.
Quick recap on this section:
- Dehydration can influence physical performance.
- Electrolyte-containing drinks are definitely helpful for hydration.
- In general, you want your drink to contain carbohydrates because they will actually help speed up hydration.
- Aside from carbohydrates and electrolytes, the concentration of the beverage is important. Beverages that are hypotonic solutions will be more beneficial than iso or hypertonic ones.
Effect of electrolytes on muscle cramping
All athletes experience muscle cramps to a certain degree. They can be painful, uncomfortable, and if they occur during your training, can negatively impact your workout, and may even inhibit your ability to finish your workout.
Not good.
The truth is that researchers don’t know exactly why muscle cramps occur, but there are two major hypotheses. The first hypothesis is that muscle cramps occur due to dehydration and shifts in electrolyte balance. The second hypothesis suggests that muscle cramping is caused by a temporary problem in the peripheral nerves, which are the nerves that connect the muscles to the brain. Essentially, the muscles contract continuously, which sends signals from the neuromuscular spindles to the brain, causing fatigue. At the same time, these continuous contractions inhibit the Golgi tendon organs, which normally help to prevent muscle cramps [6]. Nonetheless, hydration and electrolyte balance do seem to play a role in muscle cramping.
The question then is, if I drink some electrolytes during and after my training, can I reduce my risk of cramping?
There definitely is evidence that electrolyte containing beverages may be helpful for reducing your risk of cramping. That being said though, it’s important to note that the evidence for the benefits of electrolytes on muscle cramping is sparse. There just aren’t a ton of human trials investigating the effects of electrolytes on muscle cramps and theoretically, some scientists even believe that it doesn’t make sense that electrolyte beverages would be beneficial for preventing cramps because it would be very difficult to consume enough electrolytes to match the amount lost via sweat during exercise [7]. That being said though, there are a few trials that actually show that electrolyte-containing beverages can indeed help reduce risk of cramping. Let’s go ahead and review them.
First, is a series of two studies published by the same group in 2019 and 2021 that investigated the effects of water intake and electrolytes on muscle cramps during exercise [8][9]. Both of these studies had essentially the same exact study design. 10 healthy male participants who underwent a dehydration protocol through downhill running in the heat. After dehydration, the participants consumed either water or an ORS containing electrolytes. Again, ORS contains both electrolytes and carbohydrates. To test muscle cramping, the researchers used something called electrical stimulation-induced muscle cramping. Essentially, they increased the frequency of electrical stimulation to the muscles until a cramp was induced. They identified a cramp by looking for signs like a visibly tense muscle, pain, and muscle contraction. They then recorded the frequency at which the cramp occurred for further analysis. Interestingly, the researchers found that water intake after dehydration increased muscle cramp susceptibility. Perhaps because water actually further dilutes the concentration of electrolytes in your blood. On the other hand, ORS intake reduced the susceptibility of muscle cramps. Overall, both studies suggest that ingestion of ORS instead of water during and after exercise may reduce exercise-associated muscle cramps.
Another study published in 2005 investigated the effects of a carbohydrate + electrolyte drink on the onset of muscle cramps during a calf-fatiguing protocol [10]. This study is interesting because what they did was exercise participants until they experienced a cramp and what they wanted to see was whether the electrolyte beverage increased the amount of work they could do before they cramped. However, the control group wasn’t allowed to drink anything during exercise, so rather than comparing the effects of an electrolyte beverage, they compared it to nothing, which in our opinion, is not the best study design. Participants underwent a calf fatiguing protocol that included a ton of different calf exercises in the heat. The protocol is shown below, just so you can see how ridiculous it is. The researchers found that of the participants that actually cramped, exercise duration before the onset of cramping was more than doubled in the carbohydrate-electrolyte trial (36.8 ± 17.3 minutes) compared with the hypohydration trial (14.6 ± 5.0 minutes, P < .01), indicating that the electrolyte beverage increased the participants work capacity before experiencing cramping.
Quick recap on this section:
- Muscle cramps are common in athletes and can negatively impact workouts.
- The exact cause of muscle cramps is not known, but dehydration and electrolyte imbalances as well as nerve issues are possible factors.
- While there is limited evidence, some studies suggest that electrolyte-containing drinks may reduce the risk of muscle cramping during and after exercise.
- In particular, two studies found that consuming ORS instead of water reduced susceptibility to muscle cramps in a group of male participants who underwent a dehydration protocol through downhill running in the heat.
Effects of Electrolyte Beverages on Perceived Exertion and Performance
Another negative side effect of dehydration is higher perceived exertion during exercise. In other words, exercise that is objectively the same intensity just feels more difficult when you’re dehydrated.
A 2022 systematic review and meta-analysis found that on average, RPE increased by 0.21 points for every additional 1% of dehydration. Furthermore, for dehydration between 0.5 to 3% of total body weight, there was a max difference of ~0.8 RPE points compared to being properly hydrated [11]. RPE was measured using the Borg scale, which goes from 6-20, where higher values indicate greater perceived exertion. The authors mentioned that it seems like hydration status doesn’t practically impact perceived exertion until individuals are dehydrated by more than 3% of total body weight, but I do not agree with this at all. A 0.8-point increase in RPE is essentially a 5% increase in perceived exertion. It might mean a difference of 5 lbs. on the bar or running a little faster, both of which can be important for individuals trying to maximize performance.
Given that electrolyte beverages, in particular those containing carbohydrates, can improve hydration status, there’s definitely reason to believe that they may be helpful for improving perceived exertion and performance during exercise.
For example, a 2008 study looked at how much water loss and dehydration occur during one hour of paddling on a kayak ergometer, and how effective rehydration with water or a sports drink (Gatorade) is [12]. As you guys probably know, Gatorade is a sports drink that contains both electrolytes and carbohydrates. The researchers monitored ten national-level kayakers who rehydrated themselves with either water or Gatorade during the exercise. They found that kayakers who drank water lost more body mass and experienced higher ratings of perceived exertion at the 30th and 60th minute mark than those who drank Gatorade.
Another study published in 2015 looked at the effects of a carbohydrate-electrolyte drink on active women during a prolonged session of submaximal running [13]. Eight healthy women were asked to run on a treadmill until exhaustion, while consuming either the drink or a placebo every 20 minutes. The study found that there were no differences in RPE between women who drank the carbohydrate-electrolyte drink and those that drank the placebo. That being said though, those who consumed the carbohydrate-electrolyte drink were able to run for 16% longer than those who drank the placebo indicating that while RPE was similar in both groups, the carbohydrate-electrolyte drink improved work capacity.
Another study published in 2017 looked at the effects of drinking a 12% carbohydrate-electrolyte beverage during simulated soccer match-play. The players drank either a carbohydrate drink, a placebo drink or water at specific times during the game [14]. Similar to the previous study, the carbohydrate drink didn’t necessarily improve RPE, but it did improve players' performance during self-paced exercise and dribbling speed, compared to water and the placebo drink.
Collectively, the findings of these studies suggest that a carbohydrate-electrolyte drink doesn’t necessarily decrease perceived exertion during exercise. It seems that athletes push themselves equally hard during exercise independent of what they’re drinking. This makes sense, if you’re an athlete you’re going to push your body to its limits, hence why there really isn’t a difference in RPE in some of these studies. Keep in mind, RPE is simply the rating of perceived exertion, which means “how hard does the particular physical activity feel.” That being said though, performance is consistently better when hydrating with an electrolyte-carbohydrate drink compared to water. In other words, if you drink water or an electrolyte drink, you’re still likely to push your body as hard as possible, and the exercise will feel really hard, however, you’re going to perform better using a carbohydrate-electrolyte beverage.
Quick recap on this section:
- Dehydration increases perceived exertion during exercise, making it feel more difficult than it objectively is, and reduces performance.
- Electrolyte beverages, especially those containing carbohydrates, can improve hydration status and may help improve perceived exertion and performance during exercise.
- Studies have shown that drinking a carbohydrate-electrolyte beverage improves performance during exercise compared to water or a placebo, even if there is no significant decrease in RPE.
- Athletes push themselves equally hard during exercise regardless of what they're drinking, but performance is consistently better with a carbohydrate-electrolyte drink compared to water.
Should you take an electrolyte supplement for resistance training?
This is the main question we really want to answer. As mentioned earlier in this article, there really isn’t any direct scientific evidence supporting the use of electrolyte beverages in the context of resistance training. All of the research is exclusively on cardiovascular exercise.
That being said, there are some things that we can extrapolate from the available data to make an informed decision.
In any context, dehydration can lead to impairments in performance and carbohydrate-electrolyte containing beverages can help improve hydration, which should aid in performance. The majority of the evidence does suggest that these can help improve performance, endurance, reduce cramping, and improve hydration compared to just water or placebo when individuals are dehydrated.
In the context of hypertrophy training, a carbohydrate-electrolyte drink may help if you’re:
Training early morning. If you’re training first thing in the morning it’s likely that you’re starting your training session slightly dehydrated since you haven’t been drinking fluids overnight.
Training for long periods of time. The longer you train the more dehydrated you become. Longer training sessions will benefit from using these beverages compared to shorter training sessions.
Sweating a ton during training. If you’re training in the heat, or you’re simply just a heavy sweater, you’ll likely benefit from using a carbohydrate-electrolyte beverage.
Training with really high intensity. If you’re training with high volume, performing high repetitions, and using intensity techniques like super-sets and drop-sets, you’re going to likely benefit from using these beverages.
All of these contexts result in greater dehydration, thus, will likely benefit from the use of a carbohydrate-electrolyte beverage. If you are training in a way that’s optimal for muscle growth, you’re likely going to benefit from the use of a carbohydrate-electrolyte beverage because you’re probably training for longer than an hour, you’re probably training really hard with high volume and high reps, and you’re probably using intensity techniques like drop-sets and super-sets in your training.
Furthermore, there is evidence that carbohydrates themselves prior to resistance training can be beneficial for performance if you’re training with high volume and intensity [15], so it just makes sense to combine carbohydrates with electrolytes if you want to optimize your performance as much as possible.
On the other hand, if you’re just training for 45-60 minutes, you’re in a nice cool gym environment, and you’re not training very intensely (e.g., not breathing heavily between sets or sweating hard) then you’re probably not going to benefit much from electrolyte supplementation.
It’s important to highlight the fact that an electrolyte supplement is by no means “necessary" for weight training. It’s not like you can’t make progress without it. If you simply stay hydrated by drinking just water, you’re going to be fine in most cases, and you can still build muscle. Furthermore, on the hierarchy of useful supplements for weight training, electrolytes are definitely not one of the most important. Things like whey protein, creatine, and caffeine are generally more applicable and useful. However, for those who train for long periods of time, push themselves hard, and sweat a lot, then a carbohydrate-electrolyte beverage might be worth using.
References
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9. Lau, Wing Yin et al. “Effect of oral rehydration solution versus spring water intake during exercise in the heat on muscle cramp susceptibility of young men.” Journal of the International Society of Sports Nutrition vol. 18,1 22. 15 Mar. 2021, doi:10.1186/s12970-021-00414-8
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