Sweat.  It leaves white marks on your clothes. It burns your eyes. It corrodes your cables. It tastes salty.

Sweat is absolutely essential to exercise because it is our body’s most important means of cooling off.  We produce a lot of it when we’re exercising – as you can see in Table 1.  

These amounts are averages and for discussion purposes only.  There is wide variation between people and how their sweat rates differ in environmental conditions.  Generally, men sweat more than women, and we all sweat more the harder we work and the more heat stress we are exposed to in the environment.

Sweat tastes salty because it is salty.  It is full of electrolytes, especially sodium and chloride.  

Table 2 lists the average electrolyte content of sweat.  Again, these are averages and there is a great deal of individual difference. However, notice how much more sodium and chloride are in sweat than any of the other electrolytes.

So, why do we put sodium in SWORD®? For an athlete, sodium is king. Sodium (Na+) is an essential positive ion that can be found in almost every fluid in our body. It helps transmit signals down the nerves, from the brain to our muscles.  It also helps our body maintain proper fluid balance. This is important for temperature regulation, ensuring maximal oxygen and nutrient movement to working muscles. There is plenty of debate about this, but expert opinion suggests it also has a large role in the development of muscle cramps.  Despite a salty reputation, we choose to focus solely on the power of sodium for performance in our endurance drink mix SWORD®. We believe that those who are serious about their passion most likely consume a colorful balanced diet and shy away from the salt-infused food groups plaguing much of the processed and fast-food industry. In terms of the athletic performance benefit of sodium:  

1) It has many important physiologic functions essential to peak athletic performance

2) It is the most prevalent (by far) positive ion in sweat

3) We can lose a lot of sweat (and therefore sodium) when we’re working hard.

4) Sodium is known to distribute water to the extracellular space and keep it there

5) Sodium is an essential component to the intestinal absorption of carbohydrate fuels 

Why don’t we put other electrolytes in SWORD®?  We recognize that their are 4 positively charged electrolytes lost in sweat, each with their own special function in our body. But the fact is, you’re just not losing that much potassium, calcium, or magnesium during most activities to warrant replenishment from a drink source during exercise. Research studies have shown that in order to warrant the replenishment of any additional K+, Ca+, and Mg+, one must be exercising vigorously non-stop for more than 4 hours. Now we know many people who drink SWORD® do exercise for 4+ hours, and in fact, our founders are two of them. If you're into the ultra endurance distances, we expect your diet to be rich in vitamins, minerals, and essential electrolytes which the body is designed to store for use on demand. During those 4+ hours of exercise, we also expect you to take in other forms of fuel and sustenance that contain K+, Ca+, and Mg+, adequate for the minor replenishment recommended. Furthermore, adding additional electrolytes just increases the osmolality of a fluid and increases the likelihood that it will upset your stomach.  We believe in keeping things simple so you can keep pushing.
Bottom Line: We feel that for those 3 hours and 59 minutes in-between, the simplicity and power of a sodium-only fluid is the critical electrolyte to maintain speed, stamina, cognitive function, and a happy stomach. Consuming a well balanced diet and other sources of fuel that contain minor amounts of other electrolytes are an adequate source to compliment the electrolyte values lost in sweat. Consuming a sodium-only electrolyte fluid, as found in SWORD®, provides the essential ingredients to maintain efficient processes in your body that allow us to perform at our peak potential for hours on end.
 
Specifically why no Potassium electrolytes in SWORD®?
Potassium (K+), the other well known hydration electrolyte, like sodium carries a positive charge. The big difference comes down to it's size (~39 u) and physiologic function which preferentially maintains the hydration status of the intracellular space (See scientific reference). This means that when a free potassium sees a molecule of water, it latches on and then by concentration gradient, is moved inside our cells, taking water along for the ride.
During exercise, the most critical fluid compartment to maintain for an athlete is the extracellular space (the fluid outside of our cells, like our circulating blood volume). It is responsible for the transport of it's components like water, oxygen, carbon dioxide, lactic acid, glucose, and other vital elements needed to sustain cellular performance.
*If you think of this in real-world terms, our extracellular space is like the highway, our intracellular space is like a parking lot, and cars are like glucose, oxygen, carbon-dioxide, and lactic acid. During exercise, you want those cars moving on the highway to transport their essential components efficiently, not stuck in parking lots.
Consuming beverages that primarily contain potassium or high concentrations of potassium electrolytes can preferentially shuttle water away from the extracellular space and into the cells for storage, robbing the critical extracellular fluid space(s) of water and subsequent transport performance. SWORD® utilizes a physiologically relevant blend of sodium (NaCl & NaCHO) in a concentration extremely similar to published values of the average concentration of sodium lost during exercise (see above). Once absorbed, additional positively charged electrolytes found in drinks like coconut water, compete for the internal distribution of water against sodium, therefore creating fluid shifts, ultimately decreasing your athletic performance.
Bottom Line: While potassium is an electrolyte lost in sweat and is essential to the normal function of our body, in terms of maximizing athletic performance, additional ingestion of potassium just causes traffic jams. Potassium will compete with sodium to pull water away from our vital circulation, potentially slowing down the movement of essential molecules like oxygen, carbon-dioxide, and lactic acid, contributing to a decrease in efficiency and performance. A healthy and colorful diet will keep substantial stores of potassium to quickly replenish the little lost when we sweat, but do not belong in a drink when we're pushing our body to it's athletic limits.  

Overall
Replenishing sodium electrolytes during exercise can support your overall ability to perform at your peak for hours. Sodium only ingestion from SWORD® will maintain superior hydration status by minimizing cellular fluid shifts, improving and maintaining your mental clarity, and minimizing excess fluid loss by the kidneys by holding it in our vital blood volume. Plus, if you regularly experience muscle cramps, consumption of SWORD® has been the new go-to method for athletes, athletic trainers, and medical professionals as a quick and easy way to avoid them completely or having to administer an IV to help. Furthermore, sodium plays a substantial role in delaying the feeling of fatigue and tiredness by aiding in carbohydrate absorption. Sodium works with water to limit gut distress with a low osmolality and reduces bloating by speeding carbohydrate absorption across the small intestine. Finally, sodium replenishment ensures responsive brain function even under stress and keeps our muscles contracting. So when you want dig deep at the end of the race and kick, you and the competition will be blown away by your endurance.  

Get out there and work hard. Push your boundaries.

This is the second subject in our Sword 101 series. Read about Carbohydrates next.