Muscle cramps? The importance of electrolytes in sports

Conversations with active people make it clear that muscle cramps during sports, especially during long endurance exercise on hot days, occur quite frequently. 

In the following article, the causes of muscle cramps will be discussed, the role of electrolytes will be pointed out, and finally, possible strategies to avoid these painful conditions will be presented.

As mentioned above, muscle cramps are a very common phenomenon. 50 to 95 percent of all athletes are affected. If you browse the current scientific literature or rely on your own experience working with athletes, several theories emerge. The most widely accepted are:

  1. The dehydration/electrolyte theory

This theory states that a disruption of the fluid and electrolyte balance, usually due to a significant reduction in the body's overall sodium and potassium stores, a contraction of the interstitial fluid compartment around the muscles, and an excessive misfiring of nerve impulses, leads to cramps.

Put a little more simply: if you lose a lot of sodium and potassium, as is common with heavy sweating, or if you do not replace this loss with electrolyte-rich sports drinks – like our RACE BLEND from NO CARBS, NO GLORY! – this can lead to fluid shifts in the body and the resulting muscle cramps.

Overall, this theory is accepted in scientific circles, proven in many case studies, and also confirmed by us based on personal experience. Because in some self-experiments we were able to observe that generally, even more clearly on hot days!, muscle cramps can be prevented by a high salt (electrolyte) intake.
 

  1. The neuromuscular theory

This theory is based on the knowledge that muscle overload and neuromuscular fatigue are the causes of cramps. Specific nerve cells in the spinal cord control muscle activity. These cells are called alpha motor neurons. If they are overstimulated by overload, a muscle cramp occurs. 

It is also hypothetically discussed that the overuse of the muscles leads to an imbalance between excitatory impulses from muscle spindles and inhibitory impulses from Golgi tendon organs. This circumstance could lead to a localized muscle cramp.

The neuromuscular theory can also be supported by the fact that stretching the affected muscles is a fairly universally effective method to relieve a cramp when it actually occurs. Stretching puts the muscle under tension, and afferent activities of the Golgi tendon organs (a part of the muscle responsible for relaxing it) are triggered, so that the cramp eventually subsides.

But let's briefly dive into the world of electrolytes and their functions:

  • Electrolytes are among the minerals, more precisely the macroelements. Specifically, they are calcium, phosphorus, magnesium, sodium, chloride, and potassium. 
  • Electrolytes, especially sodium, regulate the water and acid-base balance of the organism and ensure optimal hydration. They are also responsible for nerve conduction and thus for the effectiveness of nerve impulses.
  • Electrolytes are of crucial importance for sports performance and recovery. During intense sessions and competitions on hot days, increased sweating leads to significant electrolyte losses, causing dehydration, muscle fatigue, increased carbohydrate consumption, and reduced performance. Hyponatremia (too low a sodium level in the blood) with accompanying muscle cramps and a severe drop in performance is not an uncommon phenomenon in long endurance competitions. The reasons are primarily the poorly tolerated carbohydrate mix of some sports drinks and also their low electrolyte (salt) content. This leads to severe digestive problems and the need to drink only more water, which results in the symptoms described above.

What strategies for avoiding muscle cramps can now be derived from this? 

The quintessence of all the studies, investigations, and self-tests conducted so far seems to be that muscle cramps probably have multiple causes, including, (but not limited to) electrolyte imbalances and neuromuscular fatigue, and that consequently probably several levers are required to effectively eliminate the different causes of cramps. The causes can be different for every person.

Important strategies follow:

  • Adequate fluid supply, which should be at least 0.5-1 liter of water, but ideally should be determined individually. We will go into this in detail in another blog post. 
  • High sodium intake, especially important on hot days and during long sports sessions: it is very important to pay attention to a high sodium content in sports drinks. It is not uncommon to consume 1.5g of sodium per liter with high sweat loss. So this would result in a minimum content of 1.5g of salt per 100g of drink powder. In our RACE BLEND from NCNG, we have taken this value into account and even use 1.9g per 100g of drink powder.
  • Sufficient carbohydrate intake. We recommend at least 60g, for long sessions from 2 hours even 90g, and beyond that up to 120g/hour.
  • Magnesium is highly essential as a mineral, since it is involved in 400 different metabolic reactions, and is also responsible for muscle relaxation, to name just a few essential functions. Therefore, it is necessary to eat magnesium-rich foods on the one hand and take a high-quality supplement on the other (we will report on this in another blog post). Whether a magnesium deficiency is responsible for muscle cramps remains to be seen. There is no conclusive scientific data on this. 
  • Pay attention to the acid-base balance in everyday eating – high vegetable and fruit content! 
  • Regular yoga practice. 
  • Regular stretching or other relaxation techniques for recovery.
  • Cucumber vinegar drink (see below)

lThe cucumber juice

In the last five years (and in some connection with the rise of the neuromuscular theory), there has been great interest in the use of compounds that can stimulate something in the mouth, which is referred to as "Transient Receptor Potential (TRP) channels".

TRP channels connect the mouth with the central nervous system, and the hypothesis is that the stimulation of these receptors triggers a nerve impulse that alleviates or stops cramps. Substances that stimulate TRP channels include wasabi, mustard oil, and other spicy spices. Cucumber juice pickled in vinegar contains acetic acid, and it is assumed that this (instead of the high sodium content) stimulates the TRP receptors and leads to the relief of cramps. From our own experience, we can say that cucumber juice can help with cramps.
 

Literature:

Jeukendrup, A. E. (2011). Nutrition in endurance sports: Marathon, triathlon and road cycling. Food, Nutrition and Sports Performance III, 

German Federal Centre for Nutrition, "What's in Food: Vitamins and Minerals: New Reference Values for Sodium, Chloride and Potassium". https://www.bzfe.de/inhalt/was-im-essen-steckt-vitamine-und-mineralstoffe-1307.html (June 05, 2018).

"Selected Questions and Answers on Potassium". https://www.dge.de/wissenschaft/weitere-publikationen/faqs/kalium/ (June 05, 2018).

"Selected Questions and Answers on Table Salt". https://www.dge.de/?id=485 2018.

More on sports nutrition at: www.ssns.ch
Annual conference on sports nutrition on June 2, 2022 i Top speakers.