As everyone should know by now, unless you’re doing light workout, you’re going to sweat and lose electrolytes, and you’ll need some replacement, both during and after your exercise routine. The popularity of flavored sports drinks stems from the fact that they were developed to replace lost electrolytes, primarily sodium, as well provide a modicum of carbohydrate to provide some energy. Not only are the electrolytes important in an exercise drink, but the carbohydrate becomes more important to provide additional energy and prolong the onset of fatigue and burnout.
An isotonic electrolyte replacement beverage may rehydrate and replace electrolytes, but without added carbohydrate, energy production resulting from consumption of the drink, would be minimal. Thus, carbohydrates, and as such, calories, must be consumed to provide the added energy boost needed for enhanced performance.
The physiology behind this is simple. When people exercise they utilize their body’s reserves of high energy phosphates, ATP (adenosine triphosphate) and PCr (phosphocreatine), to provide the energy needed to sustain the intensity of the workout. However, these phosphates are in short supply and would be used up in a matter of seconds to minutes, if they were not replaced by both the metabolism of carbohydrates, proteins and fats. The metabolism of carbohydrates involves the chemical breakdown of a substance called glycogen, in a process called glycolysis. Glycogen molecules are first broken down to sugars which are then further metabolized to provide the energy source to replace the high energy phosphates, which in turn provide the energy the muscles need for continued exercise.
The body stores glycogen primarily in the liver and the muscle, but these stores can also be depleted in a matter of 1 to 2 hours, unless they are replaced. The body has elaborate mechanisms by which it regulates the balance of high energy phosphates and glycogen, but suffice it to say, that an athlete can extend the time of exercise if external sugars, such as dextrose (glucose) are provided. Countless studies have shown the advantages of consumption of carbohydrate in various forms as a means of increasing endurance and prolonging the time-to-fatigue during exercise.
Over the past 5 to 10 years, it has become increasing evident through numerous physiological studies, that the addition of protein to carbohydrate beverages can not only prolong the time-to-fatigue during exercise, but can enhance performance, enhance recovery and protect the muscle. The precise physiological and biochemical mechanisms for this action are not yet fully elucidated, but the effects are not simply due to additional calories being derived from the added protein. Dr. Mike Saunders, Ph.D., renowned sports physiologist from James Madison University in Virginia, has shown that the addition of whey and casein proteins can prolong the time to fatigue as well as increase performance during exercise. Importantly, he demonstrated that the increased energy output exhibited by those athletes consuming protein along with carbohydrate is significantly greater than the amount of energy gained from the extra calories derived from the added protein. In other words, adding extra carbohydrate to provide the same amount of calories as derived from the protein did not account for the enhanced performance. Furthermore, when measures of muscle damage were made, Dr. Saunders demonstrated that the addition of protein has protective effects, in that less leakage of enzymes, such as creatine phosphokinase (CPK) from the muscle tissue, a marker of muscle damage, occurs in those subjects consuming the protein.
Just as athletes strive to increase their performance during exercise, they are also very concerned about the process of recovery so they can continue at full capacity in another round of exercise and/or competition. After completion of moderate to intense exercise, the body immediately ramps up the biosynthetic repair process and attempts to restore its depleted glycogen stores. It does this primarily from circulating carbohydrates, and as such, the consumption of carbohydrate sports drinks after exercise is highly recommended to augment this process. However, if insufficient amounts of carbohydrate are available for the synthesis of glycogen, the body simply breaks down muscle protein to release amino acids which are in turn used to synthesis glucose and then glycogen. Well known sports physiologist, Dr. John Ivy, Ph.D., from the University of Texas, at Austin, has shown that athletes consuming carbohydrate beverages containing protein exhibited increased rates of glycogen synthesis over those who consumed drinks with carbohydrate alone, even when the drinks were matched for carbohydrate levels or matched for total calories. The studies from Drs. Saunders and Ivy seem to support the added benefits of protein plus carbohydrate beverages, both during exercise as well as after exercise, during recovery.
The question remains, however, as to which protein and what form of protein is best to consume to achieve the ultimate in endurance and recovery after exercise. Many proteins, casein, whey, soy, etc., have been added to energy / sports drinks over the years. Most of us know all to well the bloated, gaseous, uncomfortable feeling we often get when taking whole protein, particularly whey protein, before or during exercise. It is precisely because of these reasons that most athletes usually wait until after a workout session to load up on high protein drinks containing 20 to 40 or more grams of protein, in the hopes that they will reap the beneficial effects of added protein in the process of muscle repair and rebuilding.
Internationally recognized protein biochemist, Dr. Stephen Siebrecht, from the DSM company in The Netherlands, has stated that the reason gastrointestinal problems are experienced when athletes consume protein during exercise is that proteins “. . . are relatively indigestible. The human body
cannot absorb the protein directly; it must be digested and cleaved into small peptides or separated into single amino acids, which takes both time and energy (only the very small di- and tri- peptides and single amino acids can be directly absorbed into our body).” (1). Dr. Siebrecht stated that DSM’s new protein, PeptoPro®, is a casein hydrolyzate, that contains predominately di-and tri-peptides. PeptoPro® is therefore absorbed immediately into your body, does not sit like a lead weight in your stomach, and does not cause gastrointestinal upset. It has been taken by athletes at levels up to 56 grams/serving without any gastrointestinal complaints. Through a patented enzymatic process, the bitter taste that often accompanies the digestion of various proteins has been removed from PeptoPro®. It is hypo-allergenic and forms a clear, translucent solution when dissolved in water. It is ideal for ready-to-drink (RTD) beverages for today’s athlete who wants to maximize his/her performance.
NutriBevT Science (www.nutribevscience.com), in conjunction with Nationwide Beverage Bottling, Inc. in Corona, CA, has recently released its protein sports drink, called “RADT.” It contains primarily glucose, with <2% fructose, for energy (50 calories per serving, 100 calories / ½ liter bottle), sufficient quantities of the five major electrolytes (sodium, potassium, calcium, magnesium, and phosphorous) to replace those lost during exercise, and, PeptoPro® to provide immediate protein uptake. RADT is available in a lemonade flavored drink with 5 grams of protein, with and without caffeine (100 mg/bottle), and an orange flavored 10 gram protein drink without caffeine. According to a spokesperson for NutriBevT Sciences, athletes often ask why we don't offer a sports drink with a higher concentration of protein. We inform them that we plan to produce an 18 gm protein drink containing PeptoPro® (Spring, 2007), specifically for those athletes who feel the need for higher concentrations during their recovery phase. This product will be called, "RecoveradeT." However, we point out that as of this date, the majority of studies showing enhanced performance and reduced recovery time associated with consumption of carbohydrate-protein drinks have used protein concentrations between 1-2% (10 gm/bottle). Since PeptoPro® is rapidly absorbed by the body, and does not sit in your gastrointestinal tract for several hours before being absorbed, smaller amounts of PeptoPro® may be needed to stimulate rapid glycogen synthesis after exercise. Studies are planned to answer the question regarding the amount of PeptoPro® needed to enhance recovery compared to the amounts of other, non-hydrolyzed or partially hydrolyzed protein. (1) Stephen Siebrecht, "New protein heralds next generation of sports drinks". www.nutra-ingredientsusa.com