In animals and humans the primary source of storage carbohydrate is glycogen. Glycogen is also the preferred energy source for exercise, necessary for fueling muscles, supplying glucose to the brain and it is even required for burning fat. Unfortunately, humans can only store limited amounts of glycogen. During exercise lasting longer than 90 minutes, the body can become glycogen depleted. When glycogen stores run out, exercise cannot be maintained at the same intensity and often the athlete is forced to stop. This is referred to as “bonking” or “hitting the wall”. For a more in-depth analysis of glycogen please visit the Carbohydrate Crash Course.
To prevent glycogen depletion, ingestion of 1.0 to 1.2 grams/minute of carbohydrate is needed after the first hour of endurance activity. This provides the body with the necessary energy for exercise without tapping into glycogen reserves. During prolonged exercise the mechanism behind this performance improvement is likely to be related to maintenance of high rates of carbohydrate oxidation and the prevention of hypoglycemia (47). For many athletes, carrying enough products to satisfy these needs can become heavy and cumbersome. eDISCS™ offer a compact, portable solution.
Quick absorption of nutrients is important for preventing stomach upset that can set in when the concentration of solute (or particles) remains high in the gastrointestinal tract. The process of removal of solute from the small intestine into the blood is dependent on rapid gastric (stomach) emptying, and efficient digestion and absorption in the small intestine. This need is especially amplified when exercising in the heat, when gastrointestinal discomfort occurs with increased frequency.
To avoid glycogen depletion, the rapid removal of glucose from the GI tract into the bloodstream resulting in increased blood glucose must occur, thereby sparing glycogen stores (47). The Glycemic Index (GI) of food can provide a tool to measure the effect that various carbohydrate sources have on blood glucose. The scale ranges from 0 to 100+ and the higher the GI, the faster the absorption of carbohydrate into the blood. For this reason, a high GI carbohydrate is the preferred fuel during exercise.
Carbohydrates, especially in the heat, must be able to supply quick energy, so the closer to 100 on the GI scale the better. All high GI carbohydrates are immediately available and ready to use by the body once absorbed because they require no processing in your liver, giving you the energy you need now to fuel performance; they are therefore also called 'fast burn' carbohydrates. Dextrose is certainly in this category and also has the benefit of being easy to digest and absorb, with no carbohydrate remnants passing into the large intestine (see Resistant Starch).
Dextrose, a high GI carbohydrate, was selected as eDISCS™ primary carbohydrate for several important reasons:
In the heat, especially when exercising, taste perception changes, when things that taste normal at rest suddenly seem overpowering, even nauseating (11,12). eDISCS™ have well balanced flavor during exercise-not too overpowering.
Another key ingredient in eDISCS™ is MultiCitrate™. Our bodies convert each MultiCitrate™ molecule into three bicarbonate molecules (9), and bicarbonate is the most important lactic acid buffer within. Lactic acid is produced by anaerobic metabolism, a common part of pushing yourself to the limit. Lactic acid build - up contributes to heat related illnesses, including muscle fatigue, muscle burning and cramping. It also can slow down gastric emptying (23). Neutralizing this compound can lead to improved performance and recovery.
Considering this, you may be wondering why we don't just put lots of bicarbonate in eDISCS™. In fact many companies use sodium bicarbonate in their tablets to help them dissolve. However, bicarbonate can be very irritating to the gastrointestinal tract. Through a unique manufacturing process we eliminated the need for these ingredients, and with the use of MultiCitrate™ created a natural, non-irritating tablet ideal for athletic performance.
Electrolytes (sodium, potassium, calcium, magnesium, zinc and chloride) are an incredibly important part of a sports product designed for performance in the heat, and all are lost through sweating. Electrolytes are responsible for maintaining many functions in the human body, including normal muscle contraction, blood pressure, nerve conduction, heart rate and gastrointestinal motility, to name a few. They also play an important role in energy metabolism. Allowing electrolyte concentrations to fall below normal through the process of sweating can contribute to the many problems discussed in the "Heat Stress and Heat Illness" section, including muscular cramping (13). This is a crucial issue in managing heat stress; however, most sports products have minimal and/or incomplete concentrations of electrolytes, and do very little to counter the electrolyte depleting effects of sweating.
The sodium concentration in sweat averages 800 mg/litre (39), and may average as high as 1000-1100 mg/litre, especially in hotter, more humid environments (14, 40), and varies by diet, sweating rate, hydration, and degree of heat acclimation (39). Sweat glands reabsorb sodium, but the ability to reabsorb sweat sodium does not increase with the sweating rate; thus, at high sweating rates the concentration of sodium in sweat increases (17). Falling potassium levels can contribute to all of the heat illnesses, including cramping and hyponatremia (15,16). Deficiencies in one or both of these important electrolytes can have detrimental effects on exercise performance, especially in the heat.
In addition, the sweat sodium : potassium ratio in humans is between 3:1 and 5:1. We are amazed at how many formulas out there ignore this important physiological truth. Some products even have more potassium than sodium in them. This would be great if your sweat had more potassium than sodium in it, but this isn't the case.
Also, the calcium : magnesium ratio in sweat is about 2:1, and your drink should reflect this. Replacing these important electrolytes in these ratios is important in order to optimize your function and performance, especially in the heat. Calcium is important for normal muscle contraction and nerve conduction (hence, it probably has a role in preventing muscle cramps), and replacing calcium may have role in protecting bones from reduced bone mass secondary to inadequate replacement of sweat calcium losses (38). Magnesium may also have a preventative effect on muscle cramping (13). Most sports products offer no calcium or magnesium. Finally zinc is another important electrolyte lost in sweat that is associated with optimal energy metabolism, endurance and tissue regeneration. Athletes may have a zinc deficiency induced by poor diet and loss of zinc in sweat and urine (41).
Being specifically formulated for the heat, eDISCS™ contain sodium citrate, potassium chloride, calcium carbonate, magnesium citrate and zinc citrate in amounts that reflect minimum average sweat composition. These electrolyte levels can be topped up to higher levels with the use of ZONE CAPS™, our electrolyte containing capsules, which can be used with eDISCS™ (See Customizing Your e load™). Sweat electrolyte concentration increases proportionate to sweat rate, and the e load™ customization system is founded on this principle (17).
Dear Dr. Stoddard:
As defending Rowing World Champions, my teammates and I are training hard to win again this summer in the 2008 Beijing Olympics. Training more than thirty hours per week means that fluid intake and electrolyte replacement is key to maintaining our intensity on the water. E load has been a big part of our winter training, and will be a real asset when we go into the heat of the Beijing Olympics this summer.
Kyle Hamilton 2002, 2003, 2007 Rowing World Champion, Men's Eight, 2008 Olympic Men's Eight Gold Medallists.
Congratulations to the Canadian Men's 8 Rowing 2008 Olympic Gold Champions fueled by e load!
Derek Zanstra - Mountain Bike
Ingrid Cluzeau - Duathlon
Krista Duchene: National Marathon Champion