Health and Nutrition
Influence of bicarbonate on exercise performance
As early as the 1930's, an increased exercise capacity and an increased blood lactate concentration were observed when bicarbonate was administered to volunteers prior to exercise. In view of the implications for athletic performance, it is hardly surprising that a large number of studies investigating the effects of ingestion of sodium bicarbonate or sodium citrate on the performance of high intensity exercise have been carried out since then. The results, however, are by no means consistent or conclusive.
Several investigators have reported a decrease in perceived exertion at a constant exercise intensity or an increase in performance during high intensity exercise after bicarbonate administration. Other experiments, however, have shown no benefit of an induced metabolic alkalosis on perceived exertion or performance. In one study designed to simulate athletic competition, trained non-elite (best 800 m time about 2 min 5 s) middle distance runners were used as subjects and the exercise consisted of a simulated 800 m race: when bicarbonate was given, subjects ran almost 3 s faster than in the placebo ( where the same runners were given pills that contained no bicarbonate) or control (where subjects were given nothing before the race) trials. A more recent report indicates similar improvements (3-4 s) over a distance of 1500 m in runners who completed simulated races in about 4 min 15 s. Although these effects on performance might seem small, they are of considerable significance to the athlete: an improvement of even a fraction of a second in these events is considered to be a major achievement.
Few athletes would be unhappy with an improvement of 3-4 seconds in their personal best time. These two studies were carried out completely independently, and suggest that there may be performance improvements from bicarbonate ingestion before racing. Not everyone can expect to benefit in every race, but is does appear that the use of bicarbonate is something that middle distance runners should consider.
Bicarbonate and Race Performance
Effects of Bicarbonate on 800 m and 1500 m Racing Performance
 |
Control | Placebo | Bicarbonate |
| 800m | 2:05.8 |
2:05.1 |
2:02.9 |
| 1500m | 4:18.0 |
4:15.6 |
4:13.9 |
What Events might be helped by taking Bicarbonate?
The reason for the conflicting effects reported in the published literature is not altogether clear, but some at least is probably due in part to variations in the intensity and duration of the exercise tests used, in the nature of the exercise task, in the dosage of sodium bicarbonate administered, and in the time delay between bicarbonate administration and the beginning of the exercise test (i.e. in the degree of metabolic alkalosis induced).
If the effect of bicarbonate supplementation is indeed to counter the effects of acidity caused by high rates of lactate formation, then an effect on performance would be expected only in events where muscle acidity might be a limiting factor. When exercise is of high intensity but is very short, as in the 100 m or 200 m, most of the energy is supplied by other anaerobic pathways, particularly the breakdown of creatine phosphate, and the runner is forced to slow down or stop before the muscle becomes very acid. In races longer than about 200 m, though, and muscle acidity becomes a real problem for the runner. In events lasting more than about 15- 20 minutes, the muscle acidity is not as low as it is in shorter races, and it is assumed
These observations suggest that benefits might be obtained at 400 m and at 5000 m, but that it is most likely that performance would be improved at 800 and 1500 m. Note also that there does not seem to be a benefit of using bicarbonate in training. This seems to be something for middle distance runners to use in races.
