Hydration plays a critical role in performance for anyone taking part in sport, but especially for competitive athletes.
It takes as little as a 2.5% weight loss from water to impair the capacity to perform high-intensity exercise by as much as 45%, according to one 1985 study. Adding to this, it turns out your performance is massively impacted by how hydrated you are when you start exercising in the first place.
It follows that you should pay a lot more attention to pre-hydration (or preloading, as it's known), especially before long, hot or really hard sessions. The big surprise is just how much preloading can improve your performance. We'll explain.
Activate “preload mode”
The practice of “preloading” has been widely studied in athletes and astronauts over the last 20 years. There's strong evidence that taking in additional sodium with fluids before you start sweating is effective in promoting increased endurance, particularly in the heat, but also at ambient temperature.
To understand why, let's take a step back. Within five to fifteen minutes of starting vigorous exercise you are likely to see a 10% drop in blood plasma volumes as your blood flows into your working muscles and skin, essentially leaving less available for your cardiovascular system. And, once you begin sweating, you're generally fighting an uphill battle against fluid and electrolyte loss.
Now, if you're fully hydrated beforehand, you have a larger "tank" of fluid to draw from over time. This maximizes blood volume, which improves general cardiovascular function. You also disperse heat better, keeping you cooler, reducing fatigue and ultimately enabling you to maintain your performance for longer.
The problem with coming in “hot” and under-hydrated
It's not uncommon for people to think about hydration only once they arrive for a session, as opposed to preparing in advance. This happens because those of us who are not pro athletes are juggling life and work, and aren’t always able to prepare properly - that’s just how it is.
On the flip side, a full-time athlete training multiple sessions a day also tends to under-hydrate, because uncorrected loss of fluid from a prior training session often rears its head once the next session gets underway.
But whatever the reason, under-hydration reduces athletic capability by decreasing blood flow, sweat rates and heat dissipation while increasing an athlete’s core temperature, causing energy to be used inefficiently.
Reaching for fluids at this stage may quench your thirst, but won’t give you the same boost a preload will.
The magic is in the salt, really!
According to Dr James DiNicolantonio, Author of “WIN, Achieve Peak Athletic Performance, Optimize Recovery and Become a Champion”, hydration isn’t just preventing dehydration. Hydration is about maintaining cellular hydration, blood volume and electrolyte status.
"When we have good hydration, our arteries have optimal blood volume, supplying enough oxygen to the heart, brain, skin and working muscles", Dr DiNicolantonio says. “This can be achieved only when our electrolytes are balanced and in the optimal range.”
The main electrolyte in extracellular fluid (meaning fluid found outside cells) is sodium - much of your body’s total sodium is found here. Furthermore, the total volume of extracellular fluid is directly related to the amount of sodium you have at a given time. More sodium equals more fluid. You’ll soon see why this is important. Sodium also plays a key role in the absorption of nutrients from the digestive system, and is essential for cognitive function, nerve impulse transmission and muscle contraction. Basically, you can't exist without it.
DiNicolantonio says consuming a salt solution over the course of 30 minutes, starting 90 minutes prior to exercise, will ensure optimal hydration and shoot your performance through the roof when doing high intensity exercise, long duration exercise and exercise in the heat. It is less important for low intensity exercise at ambient temperature.
Using a sodium concentration of 3,300mg per litre of water (yup, you read that correctly) and a total fluid intake of 12 ml per kg body weight is where the magic happens. The sodium number is eye-popping but that’s just because we aren't used to it. In fact, it's been almost totally overlooked. But there’s excellent science to back it up.
Let’s stop for a minute to unpack the numbers and give some examples. The first thing to note is that the amount of fluid intake is related to weight. The more you weigh, the more you need to drink beforehand, using the 12ml per kg target.
So, if you weigh 60kgs, you should be preloading with 720 ml of water (60 x 12ml). The water should contain 2,376mg of sodium. How do we get the sodium figure? We take the 3,300mg sodium per litre (or 1,000ml) and adjust it for 720ml. Our goal is to keep the sodium concentration the same. So, if we are using 72% of the water, we need 72% of the sodium. 3,300mg x 0.72 = 2,376mg.
What sodium do we use and how do we overcome the fact that it's like drinking sea water? We recommend using 1 Revive sachet which has 1,000mg of sodium and adding unprocessed salt (like Oryx Desert Salt) for the balance. 2,376mg – 1,000mg = 1,376mg: that's how much sodium to add.
How much salt do you need to get 1,376mg of sodium? One more formula (sorry). Salt is sodium chloride or NaCl. The amount of sodium in sodium chloride is 38%. So, to get 1,376mg of sodium, you need 3.6g of salt (1,376mg / 0.38 = 3,621mg). We can round this to 3.6g. A teaspoon of salt is about 5g. So, 3.6g is approximately ¾ of a teaspoon. Hopefully that’s all clear. One Revive sachet + ¾ tsp Oryx Desert Salt added to 720ml water.
Let’s do the numbers for an 80kg athlete. First the water. 80 x 12ml = 960ml. Then the sodium. 960ml is 96% of 1L so we take 96% of 3,300mg, which is 3,168mg. Then Revive, which has 1,000mg of sodium. So, the remaining sodium needed is 2,168mg. Then the salt formula: 2,168mg / 0.38 = 5,705 mg, rounded to 5.7g. Each teaspoon is 5g, so it’s 1 + a bit teaspoons of salt added to the water. One Revive sachet + 1 and a bit tsp Oryx Desert Salt added to 960ml water.
Why do we recommend Revive? It’s not just to sell a product. Aside from the sodium, Revive contains the potassium and magnesium too, which will help hydration, energy creation and maintaining muscle function. But more importantly, the flavour and stevia in Revive will make the whole solution more palatable. Otherwise, you'll be drinking salt water.
We know this sounds like a lot to digest (excuse the pun). All we will say is two words – try it. Work out the calculations for your own weight, practice it once, and the next time will be simple. And please tell us what happens to your performance. We’d love to know.
An important point to note - make sure you don't try this for the first time before a competitive event. Practice beforehand, and make sure it works for you and your gut can tolerate it.
To recap the basic idea, your blood volume drops quickly as you start vigorous exercise, even before you start sweating. Preloading with Revive + salt + water increases your blood volume to offset the pending drop. A higher blood volume means an easier time for your cardiovascular system when you’re exercising and a bigger reservoir of fluids to ‘lose’ through sweating. Once you’re into your session, you will drink less, sweat less, keep your core temperature lower, use less energy and maintain performance for longer. Boom!
The science - hocus pocus or reality?
What kind of performance increase should you expect from this preloading or pre-hydration protocol? In a profound scientific study, 13 well-trained female cyclists were asked to cycle to exhaustion at 70% of their VO2 max, at an incredibly uncomfortable temperature of 32°C. Those who consumed the high salt preload before the test were able to cycle for 20 min longer on average than those who consumed the low salt preload. Note that both consumed the same amount of fluid, so it was really a test of the sodium.
Let’s translate this “20 minutes longer” because it's a staggering number when you think about it. The average time to exhaustion with the low salt solution was 78 minutes. With the high salt solution, it was 98 minutes. That’s not just 20 minutes longer. It is a 25% increase in performance! There isn’t a drug in the world that can do that.
Is this science solid? When we read scientific studies, our default mentality is scepticism. Deep sceptisicm. Ok, we admit we are geeks for actually reading studies. But why so sceptical? Because there’s a lot of really crap science out there. Bad study design, a lot of bias, a lot of commercial interest, misinterpretation of results, big misleading headlines, academic fraud and the list goes on. All of it well-documented. So, we like to dig a bit, read the abstract, listen to different expert opinions and interpretations, think about the study design, and evaluate the results for ourselves, where possible. Often, we conclude the study is poor quality. And more times that you’d think, it is throw-in-the-bin rubbish. But every once in a while, something jumps out at us, like this study of the high sodium protocol.
Bear with us a bit as we explain. The study was particularly well designed. Firstly, it wasn’t 2 groups of athletes given different salt solutions and then compared as a group. It was each athlete, given either the high or low salt solution and tested, and then the same athlete, after sufficient rest, given the opposite solution and tested again, in the same way, under the same conditions. The athletes didn’t know which solution they were getting. That part was randomised and blinded. Some got the high salt solution first while some got it second. The researchers also didn’t know who was given which solution. This is called a double-blind study. It is also a cross-over study, meaning each participant “crosses over” and is tested on both the control and intervention. Good study design. Are there any negatives? Yes – the sample size was small; it had only 13 participants.
Because of the small sample, we really wanted to see the individual results for each athlete. Averages can hide things. What if one woman blew away the performance on the high salt solution, but 12 others had reduced performance? The average increase could still be 20 minutes but most athletes may have performed worse. We managed to uncover the actual data. Incredibly, every athlete performed better with the high salt solution. The “worst” result was a 5% improved performance and the best was a whopping 74% improvement. Stunning results. Even with a small sample size, this is compelling.
Replication is another big problem in science. Most results can't be replicated. But, we found similar studies with male runners, and we’ve looked at data for ambient conditions, in other words significantly lower than the 32°C that the female cyclists were exposed to. The performance numbers hold up. What we don’t know is whether this kind of performance improvement translates to different types of exercise, say a HIIT session in the gym. We also don’t think it is worth the effort to preload with high sodium for less intense sessions, such as zone 2 cardio, which is about 70% of maximum heart rate.
Despite this performance increase, we don’t think athletes should load-up on high sodium for ALL intense training sessions. Rather reserve the protocol for competition, super-hard days, high heat or when you are feeling flat and haven’t been performing well.
An important take-away is this though: do not ignore pre-hydration. Start your hydration before exercise, irrespective of workout type. Prepare your usual Revive, but start sipping, say an hour before your workout, and consume the rest during and after. Don’t worry as much about hydrating during your workout, unless it is hot or you’re going for a long time (more than 2 hours).
Also, it is worth emphasising post-workout hydration too. The idea is to replace what you’ve lost during a workout, both for sodium and fluid. As a rule of thumb, use 1,200mg of lost sodium per hour of sweating as a guide. This will aid recovery and ensure you perform well during your next workout. Doing this research has taught us a lot too – more emphasis on "pre and post", not as much on "during", except (as mentioned) if it’s hot or you’re going long.
One more point to note: attempting to preload with plain water inevitably just leads to more bathroom visits, as your body tries to avoid an excessive dilution of your blood sodium levels. Not a good idea, and also increases the risk of hyponatremia which is serious. That’s why electrolytes with water are important, particularly sodium.
To conclude, if you truly want to hack your performance, focus on preloading 60-90 minutes before you train and then hydrate post exercise too, to ensure you replace what was lost. You can do this with a Revive + salt + water solution. For normal training, where you don’t need the supercharge, think of Revive as the healthy pre-workout you didn't know you needed. Lastly, don’t be shy on the post workout sachet so you can reset properly and go again tomorrow.
Co-written by Jess Mouneimne and Mark Myerson
Jess is a certified health coach, certified strength and conditioning coach and professional MMA athlete. Mark is the co-founder of Revive Labs and a certified keto nutrition and diabetes coach.
Note from the authors: This article was a bit more technical than our usual, but we thought it was important to dive deeper on the topic. We hope it was a worthwhile read and not too difficult to understand.