What is Sodium Bicarbonate?
Sodium bicarbonate is a buffering agent.
Proposed Benefits of sodium bicarbonate
Supplementation with sodium bicarbonate is proposed to enhance high-intensity exercise. During exercise of high intensity the acidity of the muscle and blood increase. This decrease in pH is thought to be one of the contributors to fatigue. Sodium bicarbonate may buffer this acidic environment of muscle and blood induced by exercise. This increase in pH is thought to be beneficial by prolonging the onset of fatigue
Mechanism of Action of Sodium Bicarbonate
During high intensity muscular exercise there is a build up of hydrogen atoms in both the muscle and blood. The main fuel source of exercise of maximal intensity lasting longer than approximately 20-30 seconds is from anaerobic glycolysis (anaerobic= without oxygen; glycolysis= breakdown of glucose to provide fuel). During this type of exercise there is a progressive increase in acidity of the muscle and the blood due to the accumulation of lactate and hydrogen ions. This results in muscular fatigue and the inability to maintain exercise intensity. The exact mechanism is not fully known, but it is believed that the intracellular accumulation of hydrogen ions directly inhibits muscle contraction by impairing the role of calcium in this process. It may also reduce the activity of enzymes involved in glycolysis e.g. phosphofructokinase.
When the intracellular buffering capacity is exceeded. The lactate and hydrogen ions diffuse out of the cells. Bicarbonate is one of the most important buffers for this extracellular space.
In theory an increase in blood bicarbonate levels should delay the onset of muscular fatigue during prolonged anaerobic metabolism by increasing the muscle?s ability to dispose of the excess hydrogen ions.
Research on Sodium Bicarbonate
There have been numerous studies investigating the effects of bicarbonate loading on exercise performance. A meta-analysis was also performed on the efficacy of sodium bicarbonate on anaerobic performance (1). A meta-analysis is a statistical method where the results of many studies are combined and analysed as a whole in an attempt to investigate an affect. This meta-analysis included 35 studies with a total of 285 participants. Performance was assessed over a variety of time intervals ranging from 30 seconds to 7 minutes. Intermittent exercise was also included. This meta-analysis showed that that the ingestion of sodium bicarbonate has a moderate positive effect on exercise performance. It should be noted that there was large variation among subjects. It has been suggested that a performance benefit may only be achieved if the athlete is able to pace their performance to exploit the increased buffering capacity. Studies that fail to show an enhancement with bicarbonate ingestion may be of too short duration, of insufficient intensity to accumulate H ions, or subjects are unable to pace themselves at such challenging intensities. It is recommended that the athlete experiment individually with bicarbonate ingestion.
Other studies have also noted a performance benefit of bicarbonate ingestion for cycling exercise lasting about one hour (2,3).
Most studies have investigated the ingestion of bicarbonate 1-2 hours prior to exercise. A recent study showed improved high-intensity performance with chronic bicarbonate supplementation over 5-days (4).
A study by Swank et al noted that bicarbonate supplementation improved the perceived rating of recovery (5).
Rating of Efficacy for Sodium Bicarbonate
- Matson L.G. and Tran Z.T. Effects of sodium bicarbonate ingestion on anaerobic performance: a meta-analytical review. Int J Sports Nutr. 3:2-28, 1993.
- McNaughton L.R., Dalton B. and Palmer G. Sodium bicarbonate can be used as an ergogenic aid in high intensity cycling ergometry of 1 hour duration. Eur J Appl Physiol. 80:64-69, 1999.
- Potteiger J.A., Nickel G.L., Webster M.J., Haub M.D. and Palmer R.J. Sodium citrate ingestion enhances 30km cycling performance. Int J Sports Med. 17:7-11, 1996.
- McNaughton L.R., Backx K., Palmer G. and Strange N. Effects of chronic bicarbonate ingestion on the performance of high-intensity work. Eur J Appl Physiol. 80:333-336, 1999.
- Awant A.M. and Robertson R.J. Effect of induce alkalosis on perception of exertion during exercise recovery. Journal of Strength & Conditioning Res. 16:491-499, 2002.