In a previous blog we discussed what electrolytes are and what sodium is. We also discussed the role of sodium in a little more detail. In this blog you can find a very brief overview of some other electrolytes and their roles. Sodium and potassium are the main electrolytes in the extra-and intracellular spaces in the body respectively (fluids outside cells, for example in the blood, or inside cells (muscle cells, brain cells, etc.)). Below we will briefly discuss the role of other electrolytes. So let’s first talk about potassium:
Potassium is another electrolyte that has a really important role and is heavily regulated. Its main role in the body is to help maintain normal levels of fluid inside our cells. Potassium also helps muscles to contract, supports normal blood pressure and plays a key role in the conduction of nerve impulses. Hyperkalaemia (high potassium levels) can cause arrhythmias and cardiac arrests, but is extremely rare in otherwise healthy people.
Iron has the strongest evidence of all electrolytes. There is a clear relationship between iron deficiency and poor performance that can be restored by supplementing iron. Iron deficiency is not so easy to detect, but happens fairly regularly, especially in female athletes or athletes who restrict their food intake for longer periods of time. We discussed this topic in more detail in previous blogs. So, we refer the reader to:
Magnesium is often linked to cramping, but the evidence is very limited. What I always find fascinating is that the problem of magnesium deficiency and cramping related to it seems to be far greater in German speaking countries. Somehow the message is strongly promoted in those countries. If you speak and read English, magnesium plays less of a role in muscle cramping….. In reality, there is some limited evidence that magnesium deficiency can have an effect on nocturnal cramps, but no evidence that there is a link with exercise associated muscle cramps. Magnesium losses through sweat are very small and a balanced diet contains ample magnesium. Deficiencies are therefore extremely rare. Sometimes magnesium is measured in blood and the value measured is linked to low magnesium in the body. It is known however, that magnesium in the blood is not a good reflection of whole-body magnesium and magnesium has little or no role in the blood itself.
Although calcium is vitally important for muscle contraction and cardiovascular function and of course the maintenance of healthy bones, there is currently no evidence that calcium supplementation has any direct effect on athletic performance.
Electrolyte losses in sweat
Most of these electrolytes can be detected in sweat. However, they are only present in very small quantities and losses thus are minimal. In theory it would be possible that athletes who sweat large amounts and have diets that are inadequate are not replenishing one or more of these electrolytes on a daily basis. This theory has especially developed for calcium where the intense training of cyclists for example has been linked to low bone mineral density. However, the consensus is that there are other factors that are much more likely, such as low energy availability, vitamin D deficiency or the lack of weight bearing exercise, that are responsible for the observed low bone mineral density, not a calcium deficiency. The regulation of most electrolytes is also exquisitely controlled, and losses in one area (e.g. sweat) are often compensated for by conservation in another (e.g. less losses through urination).
In summary, apart from sodium, electrolyte losses in sweat are relatively small, and can easily be compensated through day-to-day dietary intake, and the body’s processes to conserve them in other ways. See this blog for more discussion on sodium losses.
Electrolytes in your diet
Electrolytes are important, no one argues about that. In fact, they are essential for health. But the reality is that, with the exception of perhaps iron, most athletes will get enough through their normal diet. In the media and in the world of supplements, the belief has developed that we need lots of electrolytes and these need to be ingested during exercise… Neither of these claims is true. Apart from perhaps a few very extreme situations, we can just have a balanced diet and this will supply everything we need. If you are doing an hour in the gym every day, there is no need for electrolyte drinks, or capsules or any other commercially available product. It will do no harm, but it will not have any benefits either. Because sodium is lost in greater quantities and because sodium has also received a lot of attention in the popular press, we will dive a little deeper in the evidence in the next few blogs.