Most Americans eat much more sodium than their bodies require. Too much sodium can worsen high blood pressure and heart failure. For these reasons, many Americans are advised to reduce the amount of sodium they eat. Because there is so much sodium in most foods, it is very difficult to eat too little.
But can sodium in the blood be low even if the amount of sodium in the body is too high? It can.
Low blood sodium is called “hyponatremia.” Although an underlying health condition usually causes low blood sodium levels, there are still signs that indicate if your levels are low.
What causes low blood sodium levels?
A low blood sodium level is a problem for many people.
“It usually happens with other ongoing problems,” said Dr. Kelley Anderson, a Marshfield Clinic cardiologist. “Low blood sodium rarely occurs in healthy people.”
The blood’s sodium reflects how diluted the blood is, not how much sodium is in the body.
One of the common causes of low blood sodium is heart failure. “Heart failure” means the heart is unable to supply your body with the blood flow it needs. The body tries to maintain blood flow by releasing certain hormones. Vasopressin is one of those hormones.
“When vasopressin increases, your kidneys retain pure water,” Dr. Anderson said. “That dilutes your blood, resulting in low sodium levels.”
Other causes include some mental disorders or cirrhosis of liver.
Symptoms of low blood sodium
The signs and symptoms of hyponatremia are common for a lot of other conditions. Some symptoms include nausea, vomiting, headache, confusion, feeling weak or tired, restlessness, muscle weakness, spasms or cramps and seizures or passing out.
“It can be tricky because a vast majority of people who have these symptoms may not have low sodium,” Dr. Anderson said. “Just because they have these symptoms, it doesn’t mean they have to run and get their sodium checked. So always check with your doctor first.”
A normal blood sodium level is around 140 mEq/L (milliequivalents per Liter). If it’s less than 135, it is considered low. When the level is below 130 or lower, more problems can occur.
How to treat low blood sodium levels
Blood levels of electrolytes are usually done to find out if sodium levels are low. Patients with conditions that cause hyponatremia usually have their blood checked regularly.
Dr. Anderson says most people don’t need to monitor their own sodium levels.
“In a healthy person, the body automatically maintains normal blood sodium.” Dr. Anderson said. “On the other hand, the body does not always do a good job of maintaining normal total body sodium. So people should remember sodium in your blood does not always reflect sodium in the body.”
The treatment of hyponatremia depends on how low the blood sodium is, the individual’s medical problems and their medications and dietary habits.
If you are experiencing symptoms that can be associated with low blood sodium, contact your provider.