Symptoms of a low sodium level include nausea, vomiting, headache, confusion, feeling weak or tired, restlessness, muscle weakness, spasms or cramps and seizures or passing out.
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.
For low blood sodium concerns, talk to a Marshfield Clinic Health System provider.
Schedule appointment Message your provider
My blood sodium level is 29 is this concerning?
Hello Susan,
Thank you for reaching out. We recommend discussing this directly with your provider. Due to their knowledge of your medical history and past conditions, they can best advise you.
Thank you,
Jake
Low sodium can give headaches and lightheadedness. Nephrologist suggested urea powder for my husband for low sodium because he can't take sodium, has heart failure. He's taking it for a year, no side effects.
It’s funny all you say is go seek medical help. That you cannot give advice. so, why even have people ask questions?
My thoughts exactly!! I came here because I was just diagnosed in the hospital and just released today. I'm going to follow up with my doc so yeah I'll be asking her 9 dozen questions on the first visit alone, but if I wasn't getting answers from her, where would I go, right? Frustrating.
4 years ago I had an excruciating headache. I went to the emergency room, where they determined that my sodium level was below the normal range.
They put me on a drip, and I was released.
I went to a neurologist, who found nothing, but gave me a prescription of rhizatryptan, in case of further headaches.
Since then, I started having headaches, migraine, for a 5 night period, not day, which I would treat with the rhizatryptan, but these headaches would recur, as I said, for many days.
Then, I would be okay for a few weeks, and it would happen again, for even 7 or 8 days. This has continued.
Could this be a continuation of the sodium issue?
I have normal blood pressure, 90-110 range on top- 60 on bottom.
Normal cholesterol-
Mediterranean diet-
I am 72, 5'2", 100 lbs, to give you an idea of my vitals.
Hello Mariam,
Thank you for reaching out. Unfortunately, we are limited in the medical advice we can provide on this platform. We recommend discussing these symptoms with your neurologist.
Thanks,
Jake
Is it true that a layer of salt left on the body after sweating could be an indicator of low sodium? If so, what should be done to help that problem?
Hi Nicole,
We recommend talking to your medical provider if you are experiencing this and looking for solutions. For more on the salt and sweat, you can click here: https://www.healthline.com/health/why-is-sweat-salty
Thanks,
Jake
What causes cramps in the hands and fingers?
Hi Velma,
If you are experiencing cramping in your hands and fingers, we recommend reaching out to your provider about the symptoms you are experiencing. Your doctor is most aware of your medical history and can best advise you. If you are a Marshfield Clinic patient, you can message your provider through My Marshfield Clinic at the following link: https://www.marshfieldclinic.org/mymarshfieldclinic
Thank you,
Kayla
My 14yo son was advised to take salt tablets and water, after a rapid growth rate. The effect on his complexion was remarkable. From sallow and pale to a healthy pink colour. This was after day or so. Could you give the family any idea of why this would be so?
Hello Anne,
Thanks for reaching out. We contacted Dr. Anderson – the expert featured in this blog post and here is what he had to say:
"There is not enough information to determine what was wrong or what made it better.
However, it is possible that he was essentially dehydrated, was somewhat low in both water and salt, and that his physicians treatment was successful in correcting this, making him look better due to replacement of blood volume, skin turgor etc. It is possible his body sodium and water were low for his needs. However, direct measurement of body salt is not a routine examination, and the serum sodium does not reflect whole body sodium necessarily.
To determine more precisely what the problem was and how the patient responded, one would need to interview the patient, examine the patient, obtain test results and make a determination."
If you are within the Marshfield Clinic area and would like to learn more about our heart care team, you can click here: https://www.marshfieldclinic.org/specialties/heart-care. This webpage also includes contact information and links to our specialists.
Thanks and I hope that helps,
Jake
My husbands soduim is 114. He is on kidney dialysis they say he is in danger can he get any lower
Sherri – We cannot provide individualized medical advice on our blog. It's important you ask your husband's care team any questions you have regarding his health – they are the most familiar with his current conditions and medical history. -Kirstie