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Normal Levels of Sodium in the Body

by Matthew Fox, MD

About Matthew Fox, MD

Dr. Matthew Fox graduated from the University of California with a Bachelor of Arts in molecular, cell and developmental biology and received a M.D. from the University of Virginia. He is a pathologist and has experience in internal medicine and cancer research.


Sodium is an abundant mineral in the body. It is found as an electrolyte, which is an electrically charged mineral. Sodium is important for regulation of many physiological processes, and problems with sodium are both a manifestation of disease and a cause of disease. It is important to consult with a physician for the diagnosis and management of electrolyte imbalances and other conditions.

Normal Sodium Concentration

The normal sodium concentration for average healthy adults is about 135 to 145 mEq/L. This reference range was established by measuring the sodium concentrations in many healthy people, then calculating the average and the range of deviation from the average. It is possible for healthy people to have sodium levels slightly higher or lower than these levels, but most people are normally within this range.


Sodium levels are regulated by numerous mechanisms. As examples, the renin-angiotensin system helps regulate sodium and blood pressure. When the blood pressure drops, the kidneys release the hormone renin. This converts a blood hormone called angiotensinogen to angiotensin I. The lungs convert angiotensin I to angiotensin II, which increases blood pressure and signals the adrenal glands to release aldosterone. Aldosterone, among other things, signals the kidneys to conserve sodium and water. In addition, if there is too much fluid in the blood, the heart releases the hormone ANP, which signals the kidney to release sodium and water. Antidiuretic hormone, released by the pituitary gland, signals for increased water that can decrease sodium concentrations.


Sodium helps to maintain and propagate electrical currents in the body. All cells have an electrical charge relative to the surroundings. This charge can be used to perform work or communicate. Nerve and muscle cells are very reliant on generating currents. Second, sodium helps to maintain blood pressure and blood volume. This is because blood is composed mostly of water, and water tends to follow sodium. Third, sodium helps the body absorb and transport nutrients.

Health Conditions

Hyponatremia and hypernatremia are conditions of low and high sodium, respectively. These conditions are dangerous because they interfere with muscle and nerve function, including the nerves of the brain. In addition, these conditions induce fluid imbalances in the body that can damage cells and organs. Also, over long periods of time, excessive salt intake is associated with health conditions such as high blood pressure.

References (5)

  • Robbins and Cotran Pathologic Basis of Disease; Vinay Kumar et al.
  • Harrison’s Principles of Internal Medicine; Anthony S Fauci et al.
  • Physiology; Linda S.Costanzo
  • Molecular Biology of the Cell; Bruce Alberts et al.
  • Henry's Clinical Diagnosis and Management by Laboratory Methods; Richard A. McPherson and Matthew R. Pincus

Photo Credits:

  • blood cells image by Marko Kovacevic from Fotolia.com

This article reflects the views of the writer and does not necessarily reflect the views of Jillian Michaels or JillianMichaels.com.