Wednesday, July 28, 2010

Sodium Bicarbonate: An Ergogenic Supplement From Your Cupboard

Fig. 1: Chemical structure of
sodium bicarbonate (baking soda)
In a recent post I informed you about the cumulative effect of sodium bicarbonate + beta-alanine on exercise performance. While the latter is a very popular ergogenic aid and information on dosing schemes (ranging from 1.5-6g/day, mostly in divided doses of 800mg) is readily available, the former is much less known and most of you probably think of baking soda only in the contexts of cakes and other non-fitness foods. That is why I take Tanners comment as an invitation to post some additional information on "baking soda", sodium bicarbonate or NaHCO3 on exercise performance.

The study (Craig. 2010) cited in Beta-Alanine: Positive Effects on Exercise Performance Augmented by Sodium Bicarbonate, on Friday, is only the latest of a long list of studies investigating the effect this alkalizing compound on endurance and peak performance. One of the first studies was the one by Jones (Jones. 1977). Here, the scientists provided their five male subjects with 0.3 g/kg body NaHCO3 3 hours prior to exercise and found that power output in the bicarbonate group almost doubled:
Exercise was continuous and maintained for 20 min at the two lower power outputs and for as long as possible at the highest. Compared with control (270 +/- 13 s), endurance time at the highest power output was reduced in acidosis [induced by supplementation of NH4Cl] (160 +/- 22 s) and increased in alkalosis (438 +/- 120 s). No differences were observed for central cardiovascular changes in exercise (cardiac output, frequency, or stroke volume). The respiratory changes expected from changes in blood pH were observed, with a higher alveolar ventilation in acidosis. At all power outputs arterialized venous lactate was lowest in acidosis and highest in alkalosis. Plasma glycerol and free fatty acids were lowest in acidosis. Changes in blood [HCO3-] and pH were shown to have major effects on metabolism in exercise which presumably were responsible for impaired endurance. (Jones. 1977)
Wilkes (Wilkes. 1983) demonstrated a 2% performance increase for 800m sprinting with a similar dosing protocol, as did Goldfinsh (Goldfinsh. 1988) who employed a slightly higher dosing protocol (0.4 g/kg) for 400m sprint performance.

In a relatively recent review on the effects of sodium bicarbonate loading, the authors (Requenca. 2005) conclude:
[...] the exact mechanism by which the ergogenic effects occur has not been demonstrated conclusively. Sodium bicarbonate and Na-citrate seem to be effective in activities with a sufficient duration to generate a difference in the hydrogen ion gradient, characterized by a very high intensity and involving large muscular groups. However, in activities of equally high intensity, but with longer duration, the results obtained have been conflicting and inconclusive. (Requenca. 2010)
Strength athletes and sprinters will thus derive a greater advantage from supplementation with ~20g bicarbonate (for a 70kg Athlete).

I do yet advice to exercise caution in taking those amounts of baking soda, because it may lead to gastro-intestinal distress and diarrhea. My personal advice is to start with 5g and slowly work your way up, by adding another 3 doses in equal time intervals with the last serving approximately 60 minutes before competition.

Since sodium bicarbonate can potentially elevate sodium levels in the blood it's long term use (in those doses) is debatable - my personal experience is that it appears to improves recovery even in doses of 3 teaspoons a day, taken around and during workouts.