Electrolyte Imbalance + Normal Ranges and Disturbances for Common Electrolytes


Published: 12 August 2021

Electrolyte imbalances can occur due to hundreds of factors, none of which line up in neat, tidy queues.

Look at a few of the most common examples:

  • Patients experiencing congestive heart failure often end up as rebound hospitalisations due to abnormal sodium and potassium levels
  • A grandmother with diabetes or hypertension may eventually find herself on the business end of a calcium or magnesium imbalance
  • The toddler with explosive diarrhoea and the elite Australian athlete, otherwise wildly unalike, both routinely find themselves on the business end of electrolyte imbalances.

A proper understanding of these imbalances is essential for current management and future prevention.

Screenshot from an Ausmed Lecture on electrolytes

Facts and Figures

Electrolyte imbalances occur across many different diagnostic categories.

In Australia, harsh summer environmental exposure, with resulting dehydration, is just one example of a potential root cause (Roumelioti et al. 2018); sadly, more Australians are killed from the ill-effects of heatwaves than all other natural hazards, combined (Healthdirect 2020).

This is just one potential cause, however. There are hundreds of other root causes for fluid and electrolyte imbalances, including:

  • In children: a leading cause of dehydration and electrolyte imbalance in children is acute gastroenteritis, a disorder which can be effectively treated with oral rehydration
  • In the older adult: one of the primary reasons older populations are at an elevated risk of dehydration and electrolyte imbalance is a diminished thirst response
  • In the athlete: Electrolyte imbalances during exercise come from multiple sources. Strangely, the muscles doing work do not lose water content during exercise; rather, the muscles dehydrate during the immediate post-exercise recovery period, presumably in an effort to restore plasma volume and to stabilise the cardiovascular system.

(Santillanes & Rose 2018; Picetti et al. 2017; Mora-Rodríguez et al. 2014; AIS 2021)

Electrolyte Imbalance: Normal Electrolyte Levels exercise

What is an Electrolyte Imbalance?

Put simply, electrolytes are naturally occurring minerals with an electric charge.

They exist in the human body and they are also present in food and fluids we ingest every day.

Potassium, magnesium and sodium are several commonly known electrolytes, but they are not alone; calcium and phosphate also play critical roles. These electrolytes serve crucial functions in the body such as keeping water in balance, regulating the body’s base pH levels and moving nutrients and waste to and from cells (Medline Plus 2021).

Electrolyte Imbalance Symptoms

Electrolyte imbalance can be a marker of many common diseases and illnesses.

Assessing a patient for electrolyte imbalance can give practitioners an insight into the homeostasis of the body and can serve as a marker or proxy for the presence of other illnesses.

Practitioners can use physical examination, ECGs, serum electrolyte levels and pathologic signs as methods to assess for electrolyte imbalance.

Certain symptoms can even point to a specific electrolyte that is out of balance in a patient. For example, confusion is a common symptom of hypocalcaemia (Balci et al. 2013).

By using the aforementioned examination techniques, practitioners can pinpoint which electrolytes are out of balance and thus craft a more effective treatment plan for the patient.

There are many different symptoms of electrolyte imbalance that can present themselves, including:

  • Dyspnoea
  • Fever
  • Systemic deterioration
  • Confusion
  • Oedema
  • Rales
  • Tachycardia
  • Atrial fibrillation
  • Vomiting
  • Abdominal pain.

(Balci et al. 2013)

What Causes an Electrolyte Imbalance?

Dehydration does not occur at some standardised setpoint; it is caused by consuming too little fluid for the present needs of the body.

This can happen through either decreased consumption or outside factors that cause the body to require more water than normal.

When the body becomes dehydrated, certain symptoms can arise such as dry mouth or increased thirst. However, these are not universal indicators of dehydration. In fact, they may not be clinically useful for diagnosing dehydration (Hooper 2012).

Whenever the body is overhydrated or underhydrated - or when the body’s filtration systems do not operate normally - electrolytes no longer function as they should.

Abnormal electrolyte levels can occur any time the body’s fluid levels fluctuate outside of norms, such as after serious burns, vomiting, diarrhoea or excessive sweating.

Infrequently, overhydration can also result in serious repercussions. Certain medicines and dysfunctions of the liver and kidneys can also throw the body’s electrolytes out of normal range.

Electrolyte Imbalance Risk Factors

While anyone can develop an electrolyte disorder, the older population are at increased risk.

Some factors that can increase the risk of an electrolyte imbalance in older populations include:

  • Diabetes
  • Hypertension
  • The use of diuretics (which promote fluid excretion by the kidneys).

(Liamis 2013)

Within these risk factors, there is increased risk to those who use certain combinations of diuretics and to those with diabetes. Patients who use both thiazides and benzodiazepines are associated with higher rates of hyponatremia, which, in turn, is associated with a higher mortality risk ((Liamis 2013).

The use of angiotensin-converting enzyme inhibitors (ACE inhibitors), potassium and calcium supplements and certain hormones, which are classified as potassium-sparing, can also lead to imbalances.

Other conditions that can increase the risk of an electrolyte disorder include:

Diagnosing an Electrolyte Imbalance

There are several types of tests that can be used to diagnose electrolyte imbalance.

Each type of test has its own pros and cons for detecting various types of imbalances. Here are just a few of the ways practitioners test for electrolyte dysfunction:

  • The Anion Gap Blood Test is a blood test that analyses the level of acid in the blood. This can indicate an electrolyte imbalance, as one of the functions of electrolytes is balancing the pH of the blood
  • Carbon Dioxide Blood Tests are used to measure CO2 levels in the blood. CO2 in the blood is often in the form of an electrolyte called bicarbonate
  • Chloride Tests measure the levels of chloride, another electrolyte, in the blood
  • Sodium Blood Tests analyse sodium levels in the blood, another common portion of an electrolyte blood panel.

(Medline Plus 2021)

Electrolyte Imbalance Treatment

Electrolyte Imbalance: Normal Electrolyte Levels woman drinking sports drink

Individuals who experience serious symptoms, tachycardia, mental confusion, sunken eyes, reduced elasticity of the skin and/or a loss of consciousness need immediate medical attention.

Individuals who dehydrate through exercise or activity can typically look to the electrolyte restoration possibilities of sports drinks. An excellent guide to the use of such sports drinks was put out by Australia’s AIS Sports Supplement Framework, an initiative of AIS Sports Nutrition.

Between these two extremes is a vast middle ground with some patients requiring rapid - though not emergency - medical assistance, and some patients self-correcting without ever knowing anything more than that they 'felt a bit off'.

Normal Ranges and Disturbances of Common Electrolytes

Although there are many trace elements that keep the body healthy, several important electrolytes can severely affect patients when they are either too high (hyper...) or too low (hypo...).

Understanding what each electrolyte does and what happens when there isn't enough of one or too much of another is essential knowledge for nurses and can help guide electrolyte therapy.

normal electrolyte levels infographic


normal electrolyte levels Sodium.

Sodium, or Na, is one of the most important electrolytes in the body and is responsible for a number of important functions, mostly related to fluid and water regulation. The normal accepted range for sodium is 134 to 145 mEq/L.

Hyponatraemia is considered to be a serum sodium below 134 mEq/L. A common cause of hyponatraemia is water retention due to cardiac or renal or hepatic failure.

Other causes of hyponatraemia include some medicines, psychogenic polydipsia (excessive water intake), syndrome of inappropriate antidiuretic hormone secretion (SIADH), and chronic or severe vomiting and diarrhoea.

Common symptoms of hyponatraemia include confusion, agitation, nausea and vomiting, muscle weakness, spasms and cramps.

Hypernatraemia is defined as a serum sodium greater than 145 mEq/L.

Causes of hypernatraemia are simply anything that leads to excessive water loss or salt gain. For example, water depletion or dehydration may be caused by vomiting and diarrhoea.

Excessive ingestion of sodium is rare, but the administration of infusions containing sodium such as sodium chloride or sodium bicarbonate may lead to hypernatraemia.

Clinical features of hypernatraemia may include fever, irritability, drowsiness, irritability, lethargy and confusion.


normal electrolyte levels Potassium.

Potassium, or K, is responsible for the functioning of excitable tissues such as skeletal and cardiac muscle and nerves. The normal range for potassium is 3.5 to 5.0 mmol/L.

Hypokalaemia is defined as a serum potassium less than 3.5 mmol/L. A low serum potassium may be caused by decreased oral intake, increased renal or gastrointestinal loss of potassium, or a shift of potassium within the body's fluid compartments (from outside the cell where it should be, to inside the cell).

Common clinical features of hypokalaemia range from muscle weakness and ileus (lack of peristalsis) to serious cardiac arrhythmias such as ventricular tachycardias.

Hyperkalaemia, a serum potassium greater than 5.0 mmol/L, may be caused by excessive intake, tissue damage from burns or trauma, medicines such as potassium sparing diuretics, and most commonly, renal failure.

Clinical signs of hyperkalaemia include muscle weakness, hypotension, bradycardia and loss of cardiac output. ECG changes may include peaked T waves and flattened P waves.


normal electrolyte levels Magnesium.

Magnesium, or Mg, is another element that has a strong effect on muscle contractions. The normal plasma range for magnesium is 0.70 to 0.95 mmol/L.

Hypomagnesaemia, or a decreased plasma magnesium level, may be caused by decreased intake or increased loss of magnesium. Clinical signs include confusion, irritability, delirium, muscle tremors and tachyarrhythmias.

Hypermagnesaemiais when the level of magnesium in the blood is above the normal range. Fortunately, this is uncommon. Symptoms include poor reflexes, low blood pressure, respiratory depression and cardiac arrest. It is usually caused by the excessive administration of magnesium and lithium therapy, often in the presence of renal failure.


normal electrolyte levels Calcium.

Calcium, or Ca, is an important element in the body as it helps to control nerve impulses, muscle contractions and has a role in clotting. The serum calcium range should be between 2.20 to 2.55 mmol/L when normal.

Hypocalcaemia, the presence of low serum calcium levels in the blood, is relatively rare because the bones always act as a reservoir for this electrolyte. However, parathyroid disease, vitamin D deficiency, septic shock and acute pancreatitis can cause this problem. Some symptoms include tetany (involuntary muscle contraction), mental changes and decreased cardiac output.

Hypercalcaemia, elevated levels of calcium in the blood, again arises from parathyroid problems and vitamin D issues. Signs of this form of electrolyte imbalance include nausea and vomiting, polyuria, muscular weakness and mental disturbance.


normal electrolyte levels phosphorus

Phosphate, or P, is an electrolyte used in several functions throughout the body. Although a phosphate imbalance isn't as well known as some of the other imbalances, it can still cause problems with your patient's condition. The normal range of phosphate in the plasma is generally between 0.8 to 1.3 mmol/L. The signs and symptoms of either abnormal reading are usually subtle.

For hypophosphataemia, when levels of phosphate in the blood are below the normal range, the symptoms generally include muscle weakness, heart failure, seizure and coma. It may be caused by vitamin D deficiency, hyperparathyroidism or alcoholism. Hypophosphataemia may also be present in addition to other electrolyte disturbances in re-feeding syndrome, which is associated with the commencement of total parental nutrition (TPN).

Hyperphosphataemia, when levels of phosphate in the blood are above the normal range, can be caused by kidney disease, parathyroid issues and metabolic or respiratory acidosis. Symptoms are usually not present, and they are related to hypocalcaemia. Renal patients can experience hardened calcium deposits when this condition goes untreated.

Electrolyte Imbalance Complications

Improper management of electrolyte imbalances can worsen the baseline condition.

For example, overly aggressive treatment of hypo- and hyperkalemia can cause cardiac arrhythmias (Espay 2014).

Some additional complications that can be caused by electrolyte imbalance include:

  • Arreflexic weakness due to hypermagnesemia, hyperkalemia, and hypophosphatemia
  • Epileptic encephalopathies from hypomagnesemia, dysnatremias and hypocalcemia
  • Visual loss due to intracranial hypertension caused by respiratory acidosis
  • Quadriplegia due to hypermagnesemia
  • Central pontine myelinolisis due to mistreatment of hyponatremia.

(Espay 2014)


Many electrolyte imbalances self-correct without any ill-effects. A simple drink of water can correct others.

However, electrolyte imbalances can be much more than just a nuisance - they may cause severe complications when left untreated. It is important for practitioners to correctly test for and diagnose electrolyte imbalances in order to treat them in an appropriate and timely fashion.



Andrea Salzman View profile
Andrea Salzman, MS, PT graduated from the University of Alabama at Birmingham with a Master’s degree in physical therapy in 1992. Over the last two decades, she has held numerous prominent leadership roles in the physical therapy field, with a heavy emphasis on academic writing and administrative functions. Between 1995 and 1998, Salzman served as the Editor-in-Chief of an American Physical Therapy Association (APTA) journal. In 2010, Salzman received one of the highest honors given to a physical therapist from the American Physical Therapy Association, the Judy Cirullo Leadership Award. Between 2012 and the present, Salzman has written 12 physical therapy courses for Care2Learn, Relias Learning and reviewed over 100 other course offerings. Currently, Salzman continues in her writing, leadership and administrative roles at Aquatic Therapy University and 10K Health.