Scott Riewald, PhD, CSCS, NSCA-CPT
USING SUPPLEMENTATION LEGALLY TO ENHANCE PERFORMANCE
The news these days is full of stories and feature articles on athletes who have used illegal performance enhancing drugs to boost performance and gain an advantage over their competitors. Athletes are looking for any way to get that extra “boost” in performance, and the use of prohibited ergogenic aids has infiltrated virtually every level of sport, from developmental/age group programs to the Olympics. However, not all types of supplementation are prohibited, and a quick review of the literature shows there are several legal supplements, when taken appropriately, that offer the potential to enhance training and competitive performance. For example, athletes have used sodium bicarbonate and/or sodium citrate for years to improve the body's buffering capacity, allowing them to engage in longer bouts of high-intensity exercise before the onset of fatigue. A number of research studies conducted on sodium bicarbonate and, alternatively, sodium citrate, also has substantiated their effectiveness. Recently in the International Journal of Sports Physiology and Performance, Burke and Pyne (1) provided a commentary on how these supplements have been, and can be, used to improve athletic performance in competition as well as in practice.
THE PHYSIOLOGY BEHIND BUFFERING
High-intensity activities rely primarily on anaerobic pathways, including anaerobic glycolysis, to provide the energy for working muscles. One result of using this energy system is the buildup of lactic acid and an increase in the hydrogen ion concentration in the working muscles. Although a direct link between these variables and muscle fatigue is debatable, the buildup of lactic acid and the increase in hydrogen ion concentration do contribute to metabolic acidosis; a decrease in intramuscular pH. This decrease is thought to negatively impact the force-generating characteristics of muscles and, directly or indirectly, influence the onset of muscle fatigue. Decreased pH has also been shown to adversely impact other physiological and/or metabolic functions within muscle, including enzymatic activity, impair calcium release, inhibit interaction between actin and myosin, as well as inhibit oxidative phosphorylation.
Accordingly, the principle goals of bicarbonate loading (the term bicarbonate loading is used here to include the use of sodium bicarbonate or sodium citrate) are to (a) increase the extracellular pH and improve the body's buffering capacity, allowing the working muscles to more readily deal with the excess hydrogen ions that are produced through anaerobic glycolysis, and (b) reduce the negative impact pH changes have on the physiologic functions necessary for optimal muscle function. As buffering capacity is improved, performance could be impacted through either of the following mechanisms: Delaying the onset of muscle fatigue within a competition/event and producing a shift towards anaerobic metabolism, allowing an athlete to perform at a high intensity for a longer period of time; or improving the quality of training, allowing athletes to seemingly improve more rapidly than those not using bicarbonate loading. This, in turn, would also impact performance in competition as well.
GUIDELINES: WHAT THE RESEARCH SHOWS US
The article outlines 3 distinct methods for using bicarbonate loading to enhance performance: acute loading, serial loading, and chronic loading.
Acute loading typically is used to prepare for an individual race/event and is beneficial for events during which high levels of lactate/hydrogen ions are produced and fatigue is an issue. It involves consuming a set amount of sodium bicarbonate (usually 0.3 g/kg body mass [BM]) or sodium citrate (typically 0.3-0.5 g/kg BM) with water in powder or capsule form. This dose is usually administered between 60 and 90 minutes before a competition. Many athletes find it beneficial to distribute this over 3-4 small doses as opposed to consuming the entire volume at once.
Serial loading can be used to prepare for a competition that involves multiple races a day and involves consuming the buffer in smaller doses spread across the several days preceding the competition. In this protocol, 0.3-0.5 g/kg BM of sodium bicarbonate is taken per day (split into 3-4 smaller doses) for 3-5 days leading up to the competition. This method builds up blood buffer levels that can persist for as long as 24 hours, allowing supplementation to stop the day before the competition, if desired.
Chronic loading is a newer supplementation technique and is used to support high-intensity training. Ingestion of 0.4 g/kg BM of sodium bicarbonate, taken 3 days per week for 8 weeks, led to greater improvements in lactate threshold (26% vs. 15%) and time to exhaustion when compared with a placebo in moderately trained athletes. The improvements were speculated to occur from the increased level of intensity the athletes could sustain during training because of the improved buffering capacity.
Unfortunately, bicarbonate loading is not a “slam-dunk” success with all athletes, and some experience severe gastrointestinal distress-something that is not welcome at any time, let alone in the midst of an important competition. Athletes using sodium citrate tend to report fewer complications. There are also “responders” and “nonresponders”-those who reap a benefit and those who don't. Regardless of loading scheme that is used, it is always a good idea to try things out before you get to your major competition.
As noted by the authors of this article, there are still a number of unanswered questions and unknowns when it comes to bicarbonate loading, including such topics as: How the impact is affected by food and fluid consumption; the interaction with other legal supplements like caffeine or creatine; and individualization of loading, including the amounts, number of doses, and timing needed to achieve the optimal results.
All of these questions need to be answered to truly elucidate the methodology behind bicarbonate loading, but there seems to be some promise for using these techniques to enhance training and athletic performance in high-intensity activities.