How do calcium ions affect heart functions

Minerals and heart rhythm

Cardiac arrhythmias can be due to a disturbed electrolyte balance. However, a blood test only provides limited information about the potassium and magnesium supply. Both minerals are predominantly (98 and 95 percent respectively) in the cells and only a small percentage in the blood serum. That means, even if there is an undersupply in the cells, the blood values ​​can still be in the normal range. For potassium this is between 3.6 and 4.8 mmol / l, for magnesium between 0.7 and 1.05 mmol / l.

The answer to the question of why certain minerals are so important for the heartbeat is provided by the complex biochemical process of stimulation generation and electrical stimulus transmission. The pumping activity of the heart, i.e. the relaxation and tensing of the heart muscle cells, is essentially based on interactions between various electrically charged particles (ions) inside and outside the cell. This task is carried out by the electrolyte ions sodium (Na+), Potassium (K+), Calcium (approx2+) and magnesium (Mg2+).

Decisive for the interaction of the electrolytes is their distribution and their balanced proportions. This is regulated by the intake of minerals through food and excretion, mostly through the kidneys, but also through digestion and the skin. However, some illnesses, the use of medication and the effects of our lifestyle influence the concentration of individual electrolytes. If there are significant deviations - especially in the potassium and magnesium values ​​- our heart gets out of step.


Arrhythmias are the main symptom of potassium deficiency. After severe potassium loss, e.g. As a result of diarrhea, for example, we feel physically weak and shaky.

Potassium is the most important electrolyte within the body's cells, where it is essential for stimulus generation and transmission. In addition, it is involved in many other processes in the cells and is therefore indispensable for the maintenance of various body functions. All of this always requires a certain amount of potassium in the blood. A deficiency particularly affects the nerve and muscle cells, which are then no longer properly stimulated. This can be noticeable through tiredness, decreased ability to concentrate and muscle weakness and - if the activity of the heart muscles is impaired - trigger cardiac arrhythmias.


  • is necessary for stimulus generation and transmission in nerve and muscle cells,
  • affects certain cells that protect our blood vessels,
  • if it is in a balanced ratio to sodium, it ensures stable blood pressure,
  • influences the release of hormones,
  • regulates the acid-base balance,
  • is involved in the formation of proteins and the utilization of carbohydrates,
  • has a positive effect on bone metabolism, as it prevents increased calcium excretion.

Potassium requirement

In contrast to other minerals, potassium cannot be stored and released by the body when needed. Ingested potassium that is not directly used is excreted by our body in the urine. A one-off higher potassium intake is therefore of little use; rather, we have to regularly take in a sufficient amount through our food.

The Food and Nutrition Board of the United States and Canada recommends an intake of 4.7 grams per day for adults. Based on new findings, this amount of potassium is necessary to prevent, reduce or delay chronic diseases such as increased blood pressure, salt sensitivity, kidney stones, loss of bone mass or strokes. The World Health Organization (WHO) has also changed its guidelines for the intake of potassium due to the study situation. The WHO recommendation is now: at least 3.5 grams of potassium daily, provided that a maximum of 2 grams of sodium is consumed. With a higher intake of sodium, more potassium should also be taken in.

Foods rich in potassium

Very high potassium content (over 800 mg / 100 g)

• Soybeans • Legumes • Beans • Wheat Bran • Dried Apricots • Pistachios • Tomato Paste • Cocoa

High potassium content (approx. 400 to 800 mg / 100 g)

• Fennel • Fresh spinach • Mushrooms • Potatoes • Whole grain products • Nuts • Dried fruits • Bananas

Medium-high potassium content (approx. 200 to 400 mg / 100 g)

• Celery • Cauliflower • Broccoli • Plums • Kiwi

(Daily requirement: 2000 to 4000 mg)

According to the recommendations of the German Nutrition Society, the daily potassium requirement of a healthy person is between 2 and 4 grams. However, there are new findings (see box) that include: suggest a higher potassium intake based on our current diet. So we take in more sodium through our salty diet and thus damage the healthy sodium-potassium ratio. In addition, a high proportion of animal proteins leads to increased acid formation. If we do not compensate for this by adding base-forming minerals such as potassium, magnesium or calcium, the acid-base balance is disturbed.

Adapted to our diet, there is a higher need for potassium in certain diseases and whenever more potassium is excreted. In these situations it is important to control the potassium intake and, if necessary, to increase it.

An oversupply of potassium is very rare, as too much potassium is completely excreted through the kidneys. With impaired kidney function and as a side effect of certain medications, the potassium excretion can be reduced, so that the potassium level increases. This reduces the excitability of the heart muscle and slows the heartbeat.

The potassium requirement can be increased in:

  • Stressful situations, stress,
  • increased potassium losses due to gastrointestinal infections with vomiting, diarrhea or heavy sweating,
  • Taking water tablets (diuretics),
  • Taking laxatives,
  • Diseases of the cardiovascular system,
  • Cardiac arrhythmias,
  • High blood pressure,
  • Diabetes.


After potassium, magnesium is the second most important electrolyte within the body's cells. It is also necessary for the conduction of excitation in nerve cells and muscle work and thus has an influence on our heartbeat. In addition, magnesium is required for numerous metabolic processes and provides, among other things. for the energy supply of the cells.


  • is necessary for the generation and conduction of excitation in nerve and muscle cells,
  • stabilizes the cell membranes,
  • provides energy for the body cells,
  • is important for the electrolyte balance, especially as an antagonist of calcium,
  • contributes to bone strength,
  • activated and is part of enzymes.

Foods rich in magnesium

Very high magnesium content (over 200 mg / 100 g)

• Pumpkin and sunflower seeds • Almonds • Cocoa • Wheat bran

High magnesium content (approx. 100 to 200 mg / 100 g)

• Nuts • Oatmeal • Millet • Rice • Corn

Medium-high magnesium content (approx. 50 to 100 mg / 100 g)

• Whole grain products • Swiss chard • Spinach • Peas • Crabs • Carp • Trout

(Daily requirement: 300 to 400 mg)

Magnesium requirement

The daily magnesium requirement depends on age and living conditions. Teenagers and adults need between 300 and 400 milligrams per day. The need is increased during pregnancy and breastfeeding, in active sporting phases and with long-term stress. Normally, however, it is also possible to take in sufficient magnesium through a balanced diet that is consciously rich in minerals. It can be critical in some diseases, including Cardiovascular disease and diabetes, or the use of certain medications.

In the short term, our body can compensate for an inadequate supply of magnesium by drawing on reserves. It has stored around 20 to 25 grams of magnesium, most of it in the bones. A prolonged undersupply can therefore often only be determined when the storage tanks have already been clearly emptied. Typical signs of a deficiency are cardiac arrhythmias, heart pain, muscle cramps, muscle twitching, headaches, migraines, restlessness, concentration disorders, insomnia and increased susceptibility to stress. But listlessness and even depression can result from a magnesium deficiency.

An excess of magnesium is rare because the body simply excretes too much magnesium. If the dose is too high, loose stools or diarrhea can occur as a side effect.

The magnesium requirement can be increased with:

  • Stress, inner tension,
  • increased sweating (sport),
  • Taking water tablets (diuretics),
  • Diseases of the cardiovascular system,
  • Cardiac arrhythmias,
  • High blood pressure,
  • Diabetes,
  • Migraine,
  • excessive alcohol consumption.

Potassium and magnesium - essential for your heart

For the cells to function properly - this applies in particular to the excitation of nerve and heart muscle cells - potassium and magnesium must be present in the correct ratio.

Since both minerals are essential for heart function, patients with heart disease should regularly check their potassium and magnesium levels and have the heart disease clarified by a doctor.

If the need for potassium and magnesium cannot be met despite a balanced and conscious diet, it is often advisable to take a dietary nutrient supplement - ideally in a balanced combination of potassium and magnesium.

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