Fueling The Body

Carbohydrates Plus Electrolytes Sustain Performance

by George L. Redmon, PhD, ND

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The goal of drinking during exercise is to prevent excessive dehydration (2% body weight loss from water deficit) and excessive changes in electrolyte balance to avert compromised performance. Because there is considerable variability in sweating rates and sweat electrolyte content between individuals, customized fluid replacement programs are recommended. Individual sweat rates can be estimated by measuring body weight before and after exercise. During exercise, consuming beverages containing electrolytes and carbohydrates can provide benefits over water alone.

--American College of Sports Medicine

It is common knowledge that carbohydrates serve as the body’s first source of energy to fuel your efforts before and after an intense workout. Once consumed, carbohydrates break down into smaller sugars such as glucose, that get absorbed and used for energy. Any glucose not needed right away is stored in the muscles and the liver (this storage form is known as glycogen). As soon as your glycogen stores are full, any extra gets stored as fat. Therefore it would appear that carbohydrates are very beneficial and the problem with them in reference to weight gain occurs when they are consumed in excess. The fact is, as cited by nationally known researchers Drs. Susan M. Kleiner and Maggie Greenwood-Robinson—authors of High-Performance Nutrition—with strength-training or any high-intensity exercise sustained for one to three minutes, carbohydrate/muscle glycogen stores supply 95% of the fuel needed to complete that workout session. Yet, during mild to moderate aerobic or endurance exercise routines, these researchers remind us that the body uses a 50/50 combination of carbohydrates and fat to fuel your efforts. However, the longer and more intense your activity, the body shifts to 80% usage of carbohydrates. As I am sure you have surmised here, carbohydrates stored as glycogen make an easily accessible source of energy for the body to call upon as backup fuel. How long this energy supply lasts depends on the length and intensity of your workout and can range anywhere from 30 to 90 minutes or more. This is why consuming enough carbohydrates before workouts, as well as refilling your glycogen storage capacity via carbohydrates following a workout is critical. 

While the body appears to have ways to call upon backup fuel sources, metabolically, using carbs as the muscles’ and brain’s primary fuel source, physiologically is a more efficient and easier process because the body doesn’t need a boat-load of oxygen to do so. On the other hand, to mobilize, meaning extracting fat from storage sites, involves initiating a sequence of extremely complex physiological reactions that require an enormous amount of oxygen to be present. Accordingly, renowned sports medicine researchers, the late Dr. Jack H. Wilmore PhD, at the University of Texas and Dr. David L. Costill, PhD, who has served as the director of the Ball State University Human Performance Laboratory—co-authors of Physiology of Sport and Exercise—state that carbohydrates can produce nearly 20 times more energy (in the form of ATP, adenosine-triphosphate) per gram when metabolized in the presence of adequate oxygen than when generated in the oxygen-starved, anaerobic environment as your efforts intensify. This is because your body can’t take in and distribute oxygen quickly enough to use either fat or carbohydrate metabolism easily. The other negative here, is that the body will also start extracting protein from hard earned muscle tissue to fuel your efforts. This is why sports nutrition researchers insist that protein should not be thought of or used as a primary fuel source. ATP is the primary energy molecule generated in cells called the mitochondria, where energy is. It is a well-known fact that ATP is the intercellular fuel source our bodies use to carry out every innate metabolic activity that sustains life.

Suggested Intake. Barbara Day, MS, RD, CN, the former publisher of Kentuckiana Healthy Woman Magazine and radio show host of Health News, as well as a sports nutrition consultant to the Navy SEALs and the University of Louisville Athletic Department, recommends 2.27 to 3.18g of carbs (CHO) per pound of body weight per day for athletes engaging in moderate-intensity exercise for 60 to 90 minutes per day. For athletes engaging in moderate- to high-intensity endurance events for one to three hours she recommends 3.18 to 5.45g of CHO/lb/day. Additionally, researchers at Iowa State University recommend consuming 5 to 7g of carbohydrate per ounce of body weight within 30 minutes after exercise and at two-hour intervals up to six hours post-exercise.

Don’t Forget to Electrolyte Your Muscles and Body

Despite the role carbohydrates play in fueling workouts, sports nutrition researchers at the Human Performance Research Laboratory at West Texas A&M University state that it is important for athletes and fitness enthusiasts to drink beverages containing carbohydrates and electrolytes during and after training or competition. One of the mistakes athletes and fitness enthusiasts make, according to these researchers, is not replacing fluids due to sweat loss. This is an important factor in improving performance as replacing fluids based on sweat loss centers around replacing lost electrolytes. As cited in the opening comments of this article, researchers at the American College of Sports Medicine report that excessive changes in electrolyte balance will compromise performance. However, more importantly they insist that replacement of electrolytes can be established via individual sweat rates by measuring body weight before and after exercise. Moreover, one pound is equivalent to approximately 24 ounces of fluid. In short, consuming beverages containing electrolytes and carbohydrates can provide benefits over water alone during exercise. 

Furthermore, investigators at the University Medical School in Scotland also say that the aim should be to start each bout of exercise in a fluid replete state that can only be achieved if the volume of fluid lost in sweat is replenished together with sufficient electrolytes. The fact is a large body of research has confirmed that ingestion of a carbohydrate/electrolyte-based drink during both pre- and post-exercise periods maintains and restores exercise capacity more effectively than plain water. In fact, exercise physiologists at the Human Performance Research Laboratory at West Texas A&M University, from their research, insist that athletes replace sweat loss via fluid intake containing about 4 to 8% of a solution that comprises carbohydrate and electrolytes. 

Essentially, fluid replacement is important, however, fueling up with just plain water may be a major reason why you are having major bouts of energy outages during and following a workout.

Electrolyte Power

At this point, key questions begin to emerge, such as just what are electrolytes and how do they generate and sustain energy, especially muscle energy? First of all, electrolytes are minerals that the body has, via an elaborate chemical process, completely broken down into their smallest components—a process called ionization. At this point these minerals are packed or loaded with energy, comparable to touching a live electrical wire. When minerals become electrolytes they are then active and usable in human tissues, essentially ensuring that all cellular structures come alive through this electrolyte activity. Electrolytes in body fluids are the electrical energy that keeps the body functioning. The electrical power that these internal commandos generate was first demonstrated by the late Nobel Prize Winner Dr. Alexis Carrel when he kept a chicken heart alive and beating for 28 years outside the body by reproducing new cells in an electrolyte solution. What was unique (despite the obvious) about his findings was that chickens only normally live eight years.

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The Electrolyte Fire Starters 

Physiologically, the main ions of electrolytes are sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), chloride (Cl−), hydrogen phosphate (HPO42−), hydrogen carbonate (HCO3−). As a point of reference here, the electric charge symbols of plus (+) and minus (−) indicate that the substance is ionic in nature and has an imbalanced distribution of electrons, the result of what biochemical researchers call chemical dissociation (a general process in which molecules or ionic compounds separate or split into smaller particles). It is for this reason mineral electrolytes are referred to as the sparks of life as they are responsible for transferring energy and for the regeneration and rejuvenation of every cell. These ions carry electrical impulses to the brain, nerves and muscles that give commands to various areas of the body to execute specific functions. Two of the body’s main electrolytes, sodium and potassium, are lost through sweat quickly during a workout. The longer and more intense the workout, the more important it is to replace electrolytes. In fact, electrolytes are so vital to energizing life and the overall maintenance of body and organ systems that when electrolyte levels are severely compromised, this can become life-threatening, as they maintain the body’s electrical conductivity. 

Electrolytes and Muscle Power

In the fitness arena, electrolyte formulas provide critical nutrients for energy production, muscle function and fluid balance. While not discussed enough in fitness circles, electrolytes play a critical role in maintaining muscle power. The fact is muscle movement occurs via what researchers call electrical nerve conduction, which is controlled by electrolytes. Sports medicine researchers now know that both muscle tissue and neurons (cells that sends messages to and receive messages from the brain through electrical signals) are considered electric tissues of the body. Muscles and neurons are activated by electrolyte activity between fluids (extracellular, interstitial and intracellular) found in the body. For example, muscle contraction is dependent upon the presence of calcium (Ca2+), sodium (Na+) and potassium (K+). Without sufficient levels of these key electrolytes, muscle weakness or poor muscle contractions may occur. So any loss of body fluids via sweating or perspiration, for instance, increases the need for electrolytes.

Suggested Intake. Make sure your carbohydrate drink (instead of just plain water) contains ample amounts of electrolytes and consume one hour before, during and following exercise. 

Last Words 

Physicists have been telling us for a long time that the universe is a giant pulsating electrical field of energy. They have also been telling us that the body relies heavily on this electrical conductive system to survive. Similarly, sports medicine and fitness researchers keep reminding us not to forget to electrolyte ourselves for improved and sustained performance. To reiterate, the take home message, consuming beverages containing electrolytes and carbohydrates before, during and after a workout will provide substantial performance enhancing benefits over water alone. Lastly, researchers at the University of Connecticut reaffirm the benefits of hydration beforehand in the study of elite women and men cyclists, stating that if athletes drink ad libitum, meaning to meet the task ahead, they can focus on training and competition rather than being distracted by ongoing thirst sensations. AF


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