As already mentioned, pH is a measure of the hydrogenionic concentration of a substance. pH regulators can change the blood pH within certain limits. The best known are sodium bicarbonate and sodium citrate.

Function

  The pH of the blood is physiologically between 7.35 and 7.45. When this tends to drop dangerously close to the lower threshold, the body automatically increases the respiratory rate so that the amount of carbon dioxide expelled increases with exhalation. Since carbon dioxide is acidic (pH below 7), its expulsion implies that the pH of the blood rises again. Now, one of the physiological causes of lower blood pH is physical load. More specifically, when the load involves a massive use of lactacid metabolism, the muscle tends to produce a large amount of lactic acid and expel it into the bloodstream. This, of course, contributes to a reduction in blood hydrogenionic concentration. Sometimes, when the load is particularly heavy, it can happen that the blood pH drops so low that the normal defence mechanisms against excess blood acidity are not powerful enough to counter the threat. By taking alkaline products, it is possible, as they enter the blood, to buffer excess acidity and assist the body’s normal homeostatic functions aimed at maintaining physiological pH. It is worth specifying that the intake of blood pH regulators has no direct influence on performance, but only a function facilitating recovery. In fact, what hinders muscle contractility is the lactic acid present in the muscles and not that in the blood. Once the lactate produced in the muscle is expelled and released into the blood, the muscle is once again able to contract with maximum effectiveness (except for other types of fatigue). pH regulators, therefore, come in handy not so much to improve muscle contractility, but to prevent the body from resorting to extraordinary and inconvenient mechanisms to solve the problem (e.g. vomiting). Research results, although not always very clear-cut, are rather encouraging (McNaughton, 1992; Shave, 2001; Edge, 2006).

Negative notes

  In Shave’s study (2001), eight out of nine subjects experienced complaints of the gastrointestinal tract. More specifically, symptoms ranged from mild abdominal bloating and flatulence to diarrhoea. With sodium citrate there are usually fewer side effects.

Form and posology

  Products based on sodium bicarbonate and sodium citrate are mostly commercially available in the form of soluble powders. There are no general indications for athletes. It is recommended that these products be taken during loading.