Why do footballers spit so often during matches? Many people will have asked themselves this question, with the European Championship in full swing. And the answer is not difficult, although in reality there are at least a couple of reasons why we see so often spitting and phlegm on football pitches.
A first reason is physiological: the prolonged effort of running causes saliva to thicken, making it difficult to swallow, and forcing players to spit it on the ground to catch their breath. Several studies have shown that when the body is under stress due to exercise, the protein content in saliva increases, making it more viscous and dense. The reasons are not entirely clear: in part, it is probably simply due to dehydration caused by sweating, in part because we breathe more through our mouths, drying it out and pushing us to produce mucus to keep it hydrated, and in part it could depend on other physiological mechanisms that are yet to be clarified.
The result is that when you play sports you often feel the need to spit. In some disciplines, such as tennis, it is forbidden and athletes have no choice but to accept it, and drink something when possible to wash down the excess saliva. In soccer there are no similar prohibitions, and therefore players are free to spit as much and as they want during matches. A habit so common that some believe it has now gone beyond the simple need to free the mouth from excess mucus, and has transformed into a sort of superstition, obsessive compulsive ritual, or even a primitive tactic to intimidate opponents and emphasize one’s masculinity.
Another, different phenomenon is the one that occurs when we see soccer players, and other types of athletes, take a sip from a water bottle and then spit the liquid out after a few seconds, without swallowing it. In this case, it is a trick known as “mouth rinsing” or also “carb rinsing”, and it is a strategy that aims to improve physical resistance by tricking the athletes’ brains. The secret is in the liquid contained inside the water bottles: not simple water, but an energy drink based on sugars and mineral salts. The idea is to rinse with this energy solution for a few seconds, in order to activate the receptors in the mouth, which warn the brain of the imminent arrival of nutrients with which to support physical effort.
The effect should be a reduced feeling of tiredness, due (it is assumed) to the signal that reaches the muscles from the brain that authorizes them to continue performing in the belief that the body has obtained new fuel. Studies on the subject are ambivalent. Some, like a Japanese study from 2022, seem to demonstrate that carb rinsing is actually able to improve the endurance performance of athletes. Others have not found any particular effects. Regardless of its scientific nature, the technique has now taken hold, and in football it is practically ubiquitous. But why limit yourself to rinsing, and not drink the drink to really give energy to the body? Because in that way, the body would then activate the digestion mechanisms, which in turn use energy, and with a full belly athletes would feel more tired and heavy.