Low potassium in summer: symptoms and causes

Low potassium in summer: why heat can promote hypokalemia

Summer is the season when our body has to work harder to keep body temperature constant, and for this reason low potassium can be a common condition. Through sweating we lose water and mineral salts and, if these losses are not adequately replaced, tiredness, muscle weakness, cramps and a general feeling of being unwell can appear.

Among the minerals that deserve particular attention is potassium, an element that is essential for the proper functioning of muscles, nerves and the heart. When its concentration in the blood falls below normal values, the condition is called hypokalemia, commonly known as “low potassium.”

Although heat is not the only cause of hypokalemia, high temperatures can contribute to increasing the risk, especially in older people, in patients with chronic conditions, and in people who take diuretics or do intense physical activity.

Understanding the symptoms of low potassium in summer, its possible causes and the right prevention strategies is also important for protecting kidney health, since the kidneys play an essential role in maintaining electrolyte balance.

What potassium is and why it is so important

Potassium is one of the main minerals found inside the cells of our body.

It performs many essential functions:

• It regulates muscle contraction

  Every movement of our body, from simply walking to reaching for an object, depends on the proper contraction of the muscles. Potassium takes part in the electrical mechanisms that allow muscle fibers to contract and relax in a coordinated way. When its levels drop, weakness, fatigue, cramps and, in more serious cases, a reduction in muscle strength can appear.

• It takes part in the transmission of nerve impulses

  Nerve cells communicate with one another through electrical impulses. Potassium, together with sodium, is one of the main players in generating and transmitting these signals. Thanks to this delicate balance, the brain can send commands to the muscles and continuously receive information from the whole body.

• It contributes to a normal heart rhythm

  The heart is also a muscle, and its beat depends on extremely precise electrical impulses. Potassium is essential for maintaining a regular, coordinated heart rhythm. Levels that are too low or too high can alter the normal electrical activity of the heart, promoting arrhythmias that, in the most serious cases, require immediate medical treatment.

• It maintains the balance between fluids and electrolytes

  Potassium plays an essential role in how water is distributed between the inside and the outside of cells. Together with sodium, it helps maintain the proper fluid and electrolyte balance, which is indispensable for all organs to work well. In summer, when sweating increases, this balance can be disrupted more easily if fluids and mineral salts are not adequately replaced.

• It helps control blood pressure

  An adequate intake of potassium helps maintain normal blood pressure by partly balancing the effects of sodium. Numerous studies have shown that a diet rich in foods that naturally contain potassium can help control blood pressure in healthy people. However, people with kidney failure should not increase their consumption of these foods on their own, because they could end up with too much potassium in the blood.

• It takes part in kidney function

  The kidneys are the main regulators of potassium metabolism. Every day they filter the blood and eliminate excess potassium through the urine, or limit its loss when the body needs it. This sophisticated regulation system keeps the concentration of potassium in the blood stable and ensures that the whole body works properly.

The body normally keeps potassium levels within very narrow limits thanks to the action of the kidneys, which eliminate the excess or reduce its loss when necessary.

Can heat really lower potassium?

One of the most frequent questions in summer concerns the relationship between heat and potassium.

The answer is yes, but with an important clarification.

Sweating alone almost never causes a serious potassium deficiency in a healthy person. However, heat can promote conditions that increase the risk of developing hypokalemia.

These include:

• heavy sweating;
• dehydration;
• prolonged sports activity;
• summer diarrhea or vomiting;
• poor food intake;
• use of diuretic medications.

When these factors add up, especially in frail people, the risk of a significant drop in potassium increases.

Low potassium: what are the causes?

The causes of low potassium can be numerous.

The most frequent include:

• Use of diuretics

  Diuretics are one of the most frequent causes of hypokalemia, especially in people who take them to treat high blood pressure, heart failure or fluid retention. These medications increase urine production and, along with water and sodium, can also promote the loss of potassium. For this reason, people on diuretic therapy must have the checkups prescribed by their doctor at regular intervals, and the doctor will assess whether the therapy needs to be changed or whether specific dietary advice is needed.

• Diarrhea and vomiting

  Episodes of diarrhea and vomiting, which are particularly common in summer because of intestinal viruses or foodborne illnesses, can cause a rapid loss of fluids and electrolytes. If the symptoms persist for several hours or for several days, the amount of potassium lost can become significant, increasing the risk of muscle weakness, cramps and changes in heart rhythm. In children, older adults and frail people, it is important to act promptly to prevent dehydration.

• Laxative abuse

  Occasional use of laxatives, when advised by a doctor, generally does not cause problems. The case is different with abuse, or with prolonged use without medical supervision. Excessively speeding up intestinal transit can reduce the absorption of nutrients and increase the loss of potassium in the stool, promoting the onset of hypokalemia. This is a situation that always requires a medical evaluation.

• Heavy sweating combined with dehydration

  In summer, heat and physical activity increase sweating. Although sweat contains less potassium than other electrolytes such as sodium, very heavy sweating, especially when accompanied by a low fluid intake, can contribute to changing the body’s electrolyte balance. The risk increases further if the loss of fluids is combined with diarrhea, vomiting or the use of diuretic medications.

• Certain endocrine diseases

  Some endocrine disorders can also alter potassium metabolism. These include conditions characterized by excess hormone production, such as hyperaldosteronism, which prompts the kidneys to retain sodium and increase the elimination of potassium in the urine. In these cases, hypokalemia is often an important sign that helps the doctor identify the underlying disease.

• Specific kidney diseases

  Although the kidneys have the task of maintaining the proper balance of potassium, some kidney diseases can compromise this mechanism. There are in fact conditions that cause an excessive loss of potassium in the urine, even with an adequate diet. For this reason, when tests show persistently low values, the nephrologist may request further investigations to assess kidney function and identify any specific abnormalities.

• Poor food intake

  A diet low in potassium-containing foods is rarely enough, on its own, to cause significant hypokalemia in healthy people. However, in older people, in those who follow very restrictive diets, who suffer from malnutrition or who have eating disorders, an insufficient intake can contribute to the deficiency, especially if combined with other conditions that increase the loss of the mineral.

• Potassium loss through the urine

  In some situations the body eliminates more potassium than normal without the patient realizing it. Besides the use of diuretics, this can happen in the presence of certain endocrine diseases, particular kidney conditions or as a side effect of certain medications. To identify the origin of the loss, the doctor may request specific blood and urine tests, which are essential for setting up targeted treatment.

• Watch out for medications too

  Besides diuretics, there are numerous medications that can affect potassium levels in the blood, either raising or lowering them. For this reason, it is essential to avoid do-it-yourself treatment with potassium supplements or over-the-counter products. A deficiency, like an excess, of this mineral can have serious consequences, especially for the heart and for muscle function. Only the doctor, on the basis of the medical history and laboratory tests, can establish whether potassium levels really need to be corrected and with what treatment strategy.

  Some drug therapies can also change the balance of potassium, which is why it is important not to take supplements without a doctor’s advice.

Symptoms of low potassium

The symptoms of hypokalemia depend on how far the mineral has dropped.

In mild forms, the following may appear:

• tiredness;
• muscle weakness;
• easy fatigue;
• muscle cramps;
• a feeling of heaviness in the legs.

When the deficit becomes more significant, the following may occur:

• tingling;
• difficulty moving;
• reduced muscle strength;
• constipation;
• changes in heart rhythm;
• palpitations.

In the most severe cases, hypokalemia can be a potentially serious condition and require urgent treatment.

Cramps and low potassium: is there really a link?

When you suffer from summer cramps, you tend to think immediately of a potassium deficiency.

In reality, cramps can have many causes.

Potassium is one of the minerals involved in muscle function, but dehydration, loss of sodium, fatigue, intense heat and other electrolyte changes can also promote cramps.

For this reason, it is not correct to automatically take potassium supplements without knowing the real cause of the problem.

What to eat

If the doctor confirms hypokalemia, it may be useful to increase your intake of foods that are naturally rich in potassium, as far as your clinical condition allows.

The main ones include:

• bananas;
• apricots;
• melon;
• kiwi;
• avocado;
• tomatoes;
• spinach;
• potatoes;
• legumes;
• nuts and dried fruit.

However, in people with chronic kidney failure these foods may not be suitable.

For this reason, any change in diet must always be agreed with the nephrologist or the nutritionist.

Low potassium and dialysis: beware of do-it-yourself treatment

One of the most frequent mistakes is thinking that low potassium must always be corrected with food or supplements.

For patients on dialysis the situation is completely different.

In most cases the most frequent problem is too much potassium (hyperkalemia), but situations of hypokalemia can also occur.

Only the nephrologist can establish whether potassium levels really need to be corrected and how to do it.

Taking supplements on your own can in fact be dangerous.

How to prevent low potassium during the summer

Prevention comes down to a few simple everyday habits.

It is advisable to:

• stay properly hydrated;
• drink regularly throughout the day;
• follow a balanced diet;
• avoid dehydration;
• limit physical activity during the hottest hours;
• see a doctor in case of prolonged diarrhea or vomiting;
• have regular checkups if you take diuretics.

People with kidney disease, diabetes or high blood pressure should always follow the advice of their specialist.

When to see a doctor

A medical evaluation is advisable when any of the following appear:

• frequent cramps;
• persistent muscle weakness;
• marked tiredness;
• palpitations;
• changes in heartbeat;
• symptoms that do not improve with proper hydration.

A simple blood test can check potassium levels and detect any abnormalities that require further investigation. In-depth tests can be done at the laboratories of the NefroCenter Group facilities, including the Maiello laboratory.

Low potassium and high potassium: two very different conditions

When talking about electrolytes, it is important to remember that low potassium and high potassium are completely different conditions.

While hypokalemia indicates a reduction in blood levels, hyperkalemia is an increase in potassium in the blood, a situation that is particularly common in patients with chronic kidney failure.

To learn more about this topic, you can also read our guide on high potassium, which explains its causes, symptoms and prevention strategies.

The advice of NefroCenter specialists on low potassium

During the summer our body loses more fluids and mineral salts. For most people, proper hydration and a balanced diet are enough to maintain the right potassium balance.

However, people with chronic kidney disease, diabetes or high blood pressure, people who take diuretics and those on dialysis should avoid any supplementation on their own.

Potassium is an essential mineral, but it must stay within well-defined values. Both a deficiency and an excess can have serious consequences for health.

For this reason, if you have suspicious symptoms or abnormal blood test results, it is always advisable to see your doctor or your trusted nephrologist.