Overview

• Bicarbonate is the body's most important extracellular buffer. Bicarbonate loading increases the muscle's extracellular buffering capacity and ability to dispose of excess hydrogen ions produced through anaerobic glycolysis.
• Citrate loading has also been used to increase extracellular buffering capacity although some research suggests bicarbonate may be more effective (Van Montfoort et al. 2004). This area warrants further investigation given that citrate seems to be less likely to cause gut disturbances.
• Traditional protocols of bicarbonate and citrate supplementation have involved “acute” ingestion in the one to two hours before an exercise bout. 
• A meta-analysis of studies of acute bicarbonate loading concluded that it has a moderate effect-size in enhancing the performance of anaerobic exercise/events (Matson and Tran 1993).  
• Recently, a “chronic” supplementation protocol with repeated doses of bicarbonate over several days has been shown to increase buffering capacity, with effects lasting for at least 24 h following the last dose (McNaughton et al. 1999; McNaughton and Thompson 2001). This protocol warrants further investigation.
• Few studies of citrate or bicarbonate loading have been undertaken in a real sports setting.
• Effects may vary between individuals as well as between sports events. Therefore, it is essential that supplementation be supervised by a sports scientist and practiced in appropriate training sessions to assess benefits and potential side-effects for the individual athlete.

Supplement products and protocols

• Sodium bicarbonate is available in a number of forms:
o capsules (Sodibic; 0.84 g per capsule)
o effervescent powder (Ural; 1.76 g per sachet, plus additional amounts of sodium citrate)
• The acute bicarbonate loading protocol typically involves a 300 mg/kg dose, taken 1-2 hours prior to the session.
• The chronic bicarbonate loading protocol typically involves five days of 500 mg/kg bicarbonate, split into four doses over the day.

Situations for Use in Sport

• There is strong evidence for use by athletes competing in high-intensity competition events lasting 1-7 minutes.
• Some new studies show that bicarbonate supplementation may have benefits for high-intensity events of up to an hour as well as intermittent high intensity team sports.
• There is also preliminary evidence of increased training adaptations from an interval training program when acute bicarbonate supplementation is undertaken prior to each session (Edge et al. 2006). This needs to be validated within an athletic population.

Concerns Associated with Supplement Use

• Gastrointestinal distress often occurs with bicarbonate loading. This may be reduced by ingesting the capsules or dissolvable powder with sufficient fluid to decrease the osmotic ‘loading’ on the gut. Alternatively, the “chronic” bicarbonate protocol can be used in which supplementation is carried out in split doses over a number of days to increase plasma buffering capacity. Such a protocol may allow the athlete to finish their intake of bicarbonate (and the risk of gastrointestinal side effects) on the day prior to their competition, while maintaining the benefit to performance.
• Repeated use of acute loading protocols (e.g. heats and finals in a single or multi-day competition) may exacerbate the risk of side-effects. This may be reduced if the athlete uses lower doses on subsequent occasions to compensate for bicarbonate remaining in the body.  Alternatively, a chronic loading protocol could be adapted to the competition timetable.
• Changes in the pH of urine are expected following bicarbonate supplementation. If an athlete is selected for a drug test, they may need to wait several hours before urinary pH returns to the levels that are acceptable to drug testing authorities. This may cause some disruption to the athlete’s daily routine or post-event activities.
• Interaction with other supplements should be considered (e.g. caffeine, creatine).

Further Reading

Edge J, Bishop D, Goodman C. Effects of chronic NaHCO3 ingestion during interval training on changes to muscle buffer capacity, metabolism, and short-term endurance performance. J Appl Physiol 2006; 101 (3): 918-925

Matson LG, Tran ZT. Effects of sodium bicarbonate ingestion on anaerobic performance: a meta-analytic review. Int J Sport Nutr 1993; 3: 2-28

McNaughton L, Thompson D. Acute versus chronic sodium bicarbonate ingestion and anaerobic work and power output. J Sports Med Phys Fitness 2001; 41 (4): 456-462

McNaughton L, Backx K, Palmer G, Strange N. Effects of chronic bicarbonate ingestion on the performance of high-intensity work. Eur J Appl Physiol 1999; 80: 333-336

Van Montfoort MCE, Van Dieren L, Hopkins WG, Shearman JP. Effects of ingestion of bicarbonate, citrate, lactate, and chloride on sprint running. Medicine and Science in Sports and Exercise 2004; 36 (7): 1239-1243

Please refer to summary table on research conducted on bicarbonate and citrate.

Last updated August 2009.

This fact sheet was prepared by AIS Sports Nutrition as part of the AIS Sports Supplement Program.  The AIS Sports Supplement Program has been designed for the specific needs of AIS athletes and all attempts are made to stay abreast of scientific knowledge and of WADA issues related to anti-doping.  It is recommended that other athletes and groups should seek independent advice before using any supplement, and that all athletes consult the WADA List of Prohibited Substances and Methods before making decisions about the use of supplement products. © Australian Sports Commission 2009