Our normal table salt consists of sodium (Na) and chloride (Cl). 1 g of table salt contains approximately 400 mg of sodium and 600 mg of chloride. To replace 1000 mg of sodium, approximately 2.5 g of table salt is required.

Net salt loss during exercise is the product of the two factors sweat volume and the individual salt concentration in sweat. While the latter is relatively constant, the sweat volume varies, particularly with temperature and exercise intensity.

Sodium and chloride, components of table salt, are responsible, among other things, for our body's water balance. Sodium is also responsible for muscle function and improves glucose absorption in the body.

During exercise, we lose primarily salt through sweating, but also other electrolytes. To maintain optimal performance, we need to adequately replace these. Salt and sodium are very volatile, and stores can be depleted within a short period of time.

The salt concentration in sweat can vary greatly from person to person, by more than a factor of 10. Typically, it ranges from approximately 200 mg of sodium to approximately 2500 mg per liter of sweat. Almost all sports drinks are at the lower end, so it makes sense to adjust them individually.

A lack of salt can lead to muscle cramps, fatigue, and an increased risk of heat stroke. Therefore, it's important to monitor your body's salt levels, even during physical activity.

During exercise, intense sweating can lead to significant fluid loss, which reduces blood volume. This leads to increased viscosity ("thickening") of the blood and impairs oxygen transport and thus performance.

If the body retains too much water and has too little salt available, this can lead to hyponatremia (sodium deficiency). This is when the sodium concentration in the blood drops due to insufficient electrolyte intake. Typical symptoms include headaches or dizziness. In severe cases, this can even lead to coma or death.