How acidic can athletes get?

16. September 2020

Much has been said about the acid-base balance. Can you be too acidic? And are athletes more at risk of being acidic due to the constant production of lactate?

You will find products for the acid-base balance in every nutrition shop. If you read the accompanying information, acidification seems to be responsible for almost everything, ranging from general fatigue to hair loss. And the primary cause of acidification is supposed to be a diet with excess acid. While the range of products for regulating the acid-base balance reflects society’s interest in the topic, this bears no relation to the research interest.

The following generally applies: the body doesn't like to be stressed out. It prefers it when its metabolic processes are in equilibrium to a certain degree. The search for this equilibrium was already defined as homoeostasis in the 1920s, of which the acid-base balance is part. Metabolic reactions only function when there is a certain acid content in the cells or blood. The body therefore has mechanisms to control the acid content and get rid of excess acid: the buffer systems.

In blood, the most important buffers are the bicarbonate buffers and the red pigment in blood cells (haemoglobin), and in cells, there are various proteins, phosphates and - lactate. Lactate thus buffers acid and does not cause any acidification in itself. It is not the cause of «acidic» muscles in sport, as is so often claimed. With the direct splitting of the energy carrier ATP, acid or protons are released during the so-called glycolysis phase (the breakdown of glucose or glycogen into pyruvate).

Increased acid formation in sports

In the case of adults who exercise little and have a mixed diet, the metabolism produces around 800 grams of CO2 and 0.04-0.08 grams of protons per day. The buffer systems can prevent acidification here without any problem. In the case of intensive sports, 600 grams of CO2 are produced per hour and slightly more than 1 gram of protons are produced during a high-intensity load of 2-3 minutes. As a result, the acid production in those who do sports is significantly higher than in those who do hardly any physical activity. However, this is generally considered harmless - so sports and particularly endurance sports are not recognised as harmful but rather conducive to health.

So, why should the significantly lower dietary acid load be a problem when the buffer systems work well in sports? Those who take the specialist literature into account instead of the many public discussions about the acid-base balance will be surprised. Even in healthy people with a high dietary acid load, there is no noticeable increase in the risk of dying prematurely from any disease. And a high alkaline diet, incidentally, has the same effects as a high acidic diet. One exception: in the case of diseases, things may look different, so depending on the disease, it is a good idea to pay attention to your acid-base balance. The tips regarding the acid-base balance are therefore simple. If you have a disease, check with a medical specialist. Otherwise: don’t let yourself get stressed and enjoy the sport as well as the balanced diet.