Sodium Bicarbonate Doubles Athletes' Anaerobic Running Endurance -- Na-Citrate Works, Too, but is Less Effective

In 1990 Luft et al. were able to show that, unlike regular salt, of sodium bicarbonate does not trigger an increase in blood pressure - the exact opposite is the case, even if you don't sweat like an athlete.

If you follow the news and the SuppVersity Classic posts on the SuppVersity Facebook Page it has probably been only two to three weeks since you've read the last post and/or article about the pH buffer. If you belong to those SuppVersity readers, however, who devour only the articles at www.suppversity.com, you will probably have asked yourselves: "Where on earth are the articles about bicarbonate, wasn't that one of Adel's favorites?"

Well, guess what: I have been asking myself a similar question when I reviewed the most recent tables of contents of pertinent journals - there was no bicarbonate study to be seen... until, a few days ago, at least.
The study I am referring to was conducted at the School of Sport Sciences of the Surabaya State University in Indonesia (Hartono 2017) and it is particularly interesting because it did not just test the efficacy of sodium bicarbonate in a practically relevant context, i.e. the effect of supplementation on time to exhaustion during an anaerobic running test in trained individuals (University badminton players and thus athletes competing in a highly anaerobic sport), but also compared the its efficacy to that of sodium citrate, an almost forgotten pH buffer that has long been thought to be the one of the go-to supplement for athletes.

Figure 1: Afraid of too much sodium? For hard working athletes, a deliberate reduction in their salt intake may do more harm than good. For certain athletes, scientists even recommend to deliberately increase their consumption (learn more).

After an initial baseline trial, the subjects (30 badminton players, mean age 21 years) were randomly assigned to receive a placebo drink containing only 500 ml water, or...

• 300 mg/kg sodium bicarbonate in 500 ml water, or
• 300 mg/kg sodium citrate in 500 ml water

90 minutes before a treadmill test that measured their maximal running endurance from the anaerobic threshold to the time they stopped running because of exhaustion. Next to the time to exhaustion, the blood pH and bicarbonate ion content, as well as the subjects' lactate levels were measured.

Figure 2: Time to exhaustion (in min) during anaerobic phase of a treadmill running test with placebo (water only), water + 0.3g/kg sodium bicarbonate or water + 0.3g/kg sodium bicarbonate (Hartono 2017).

As you can see in Figure 2 the results leave little room for interpretation. The provision of the allegedly diarrhea-prone amount of ~20-25g of sodium bicarbonate (remember: serial loading can help you not to have to run to the toilette) lead to a statistically highly significant 103% (p = 0.029) increase in anaerobic running endurance and could - unless you have to run to the toilette - thus make a practically relevant difference for any athlete who competes in a sport with a significant anaerobic (=glucose-burning, like sprinting in football or soccer, lifting heavy objects etc.) component.

Figure 2 does yet also tell you that similar, albeit significantly less pronounced effects (the difference of bicarbonate vs. citrate has a p-value of only 0.020 and thus a ~2% chance of being only coincidental) can also be achieved by sodium citrate, which is said to be less diarrhea-prone than its bicarbonate brother. I have to warn you, though: My personal experience with the effects of sodium citrate on the digestive tract say the opposite and the results from (mostly older trials) with sodium citrate yielded even more ambiguous results than those with bicarbonate.
References:

• Luft, Friedrich C., et al. "Sodium bicarbonate and sodium chloride: effects on blood pressure and electrolyte homeostasis in normal and hypertensive man." Journal of hypertension 8.7 (1990): 663-670.
• Hartono, Soetanto. "The Effects of Sodium Bicarbonate and Sodium Citrate on Blood pH, HCO3-, Lactate Metabolism and Time to Exhaustion." Index coverage: 13.