Hypernatremia is when there's too much sodium and not enough water in your blood. Sodium is one of the electrolytes in your body, found mostly in your blood. It's important for many body functions. However, when there's too much, the imbalance can cause serious problems.
Hypernatremia: Too Much Sodium
Doctors define hypernatremia as a sodium level of over 145 milliequivalents per liter of blood — a normal level is between 136 and 145 milliequivalents per liter.
It's most likely to happen in babies or people who are older. Certain health conditions can make hypernatremia more likely. But it's often a symptom of dehydration — if you don't have enough water, your blood sodium levels can get too high.
It's also possible, but less likely, to get hypernatremia from taking in too much salt or having salt poisoning. But if you're otherwise healthy, you don't need to worry about getting hypernatremia from your diet, says Amanda Beaver, a registered dietitian nutritionist at Houston Methodist in Houston.
"If we just eat a bunch of sodium from food, it's not going to necessarily cause us to develop hypernatremia, because our body tries to closely regulate the amount of sodium that's in our blood," Beaver says.
Here's how it works: When there's a change in the balance of sodium and water, your body senses it and gets rid of more or less sodium in your pee to get back to a normal level. If the amount of sodium in your blood is getting too high, it'll trigger you to feel thirsty and drink more. Dehydration and hypernatremia can be more likely when you're older because, in part, your sense of feeling thirsty can diminish with age.
Your body will also release hormones called aldosterone and antidiuretic hormone (ADH). These cause your kidneys to hold onto more water. So, you'll see your pee look darker and more concentrated if you aren't drinking enough. Your body naturally will get rid of more sodium and less water to keep your levels in a normal range.
Even if you do get hypernatremia, most cases are mild and can be treated by taking in more fluids. If you start to get dehydrated and feel thirsty, you're sensing a mild case of hypernatremia. You can treat it by drinking water or a sports drink that contains electrolytes. Moderate or severe cases need medical care.
Hyponatremia vs. hypernatremia
Hyponatremia is the opposite of hypernatremia. It means sodium levels in your blood are too low. If sodium levels aren't high enough, it can make water move out of your blood and into your tissues and organs.
"If we're way overly hydrated, that can even be life-threatening," Beaver says. "The main thing is to just avoid extreme dehydration or overhydration."
Like hypernatremia, hyponatremia usually doesn't happen if you're healthy and your kidneys are working normally. But it can happen if you're dehydrated and then drink too much water too fast without replacing sodium or other electrolytes. Certain medicines can also cause an imbalance to make hyponatremia more likely.
Why Is Sodium Important?
Too much sodium or salt can be bad for you. But, Beaver says, "Sodium is essential for our body."
In addition to keeping the right amount of water inside and outside our cells, sodium does many other things. For example, it controls your blood volume and blood pressure. If you have more sodium in your blood, it will cause more water to enter your bloodstream. That's why eating too much salt can make high blood pressure more likely.
Your nervous system also needs sodium for sending the impulses that tell our skeletal muscles to contract. Your nerve cells pump sodium out and potassium in. When they receive a signal, sodium channels open up. This lets the sodium rush in to send a signal or impulse. If your sodium levels drop too low, it can even be life-threatening.
Symptoms of Hypernatremia
Most people with hypernatremia will show signs of dehydration. But some symptoms are also related to the effects of high sodium on the nervous system.
Symptoms of hypernatremia include:
- Restlessness
- Extreme thirst
- Confusion
- Lethargy
- Irritability or agitation
- Seizures
- Unconsciousness or coma
- Skin that feels doughy or velvety from water loss
- Low blood pressure (hypotension)
- Rapid heartbeat
- Strong reflexes
Hypernatremia Risk Factors
Any condition or circumstance that causes you to lose water without losing sodium can raise your risk for hypernatremia. These include:
- Gastroenteritis
- Vomiting
- Long-term drainage from a tube in the nose (nasogastric drainage)
- Burns
- Sweating too much from exercise, fever, or heat
- Kidney problems
- Hyperglycemia
- Reduced thirst response
In rare cases, breastfed babies can get hypernatremia because they aren't drinking enough. It can also happen in cases of child or elder abuse.
It can also happen if you take in too much sodium from:
- Formula with too much salt
- Ingesting sodium bicarbonate
- Salt tablet poisoning
- Hyperaldosteronism (too much of a hormone called aldosterone)
- Drinking or drowning in seawater
Hypernatremia and diabetes insipidus
Hypernatremia can also happen if you have diabetes insipidus. It's a rare condition caused by problems with the hormone vasopressin, which keeps your sodium and fluids balanced. The condition can cause you to pee too much. This makes dehydration and hypernatremia more likely if you don't drink enough.
Diagnosis and Treatment of Hypernatremia
A doctor can diagnose hypernatremia through a blood test. Sometimes, urine tests can be used as well.
The treatment aims to restore the normal balance of fluid and sodium in your body. Your hypernatremia treatment will depend on what's causing your high salt levels. It's usually best to restore sodium balance by drinking fluids. If your hypernatremia is more than mild, your doctor may replace the fluids in your body using an IV. This will supply fluids directly into your bloodstream, balancing the amount of sodium that's in your blood.
In most cases, hypernatremia can be fixed. But it's important not to lower sodium levels too fast. However, your doctor will want to find out why you got hypernatremia to make sure there aren't other problems that need to be treated to keep it from happening again.
Complications of Hypernatremia
One of the most severe complications of hypernatremia is a ruptured blood vessel in your brain. Called a subarachnoid or subdural hemorrhage, this kind of bleeding in your brain can cause permanent brain damage or death.
If doctors are able to detect and begin treating hypernatremia before it gets too severe, they can restore the balance of sodium and fluids in your body, preventing serious complications.
Is Too Much Sodium Bad for Weight Loss?
About 70%-80% of the sodium in U.S. diets comes from packaged, processed, restaurant, and store-bought foods. Only about 5% comes from salt added during cooking. About 6% comes from salt added at the table.
The Center for Science in the Public Interest released a report that found 85 out of 102 restaurant meals from 17 popular chains had more than a full day's worth of sodium. Some had more than four days’ worth.
"To regulate blood pressure and make sure you're not eating too much sodium in your diet, one of the hands-down, simplest ways is to just try to make some more meals at home and eat out less," Beaver says.
But reducing sodium isn't always easy, even when you cook at home. Our taste buds are used to the salty taste of most foods. And unlike sugar, there are few convincing substitutes. Not only does sodium flavor foods, but it also acts as a preservative and inhibitor in leavening agents. Sodium is found not only in salt, but also in baking soda, baking powder, and monosodium glutamate (MSG).
In the last several years, scientists have begun to examine whether salt affects obesity. Here's what they found:
- In 2015, British and Chinese researchers reported that body fat increased for children and adults on high-salt diets. Eating an extra gram of salt each day increased the risk of obesity in children by 28% and in adults by 26%. The study authors said they don't know why salt has this effect, but other studies suggest that it may change the way our bodies burn fat.
- An Australian study in 2022 linked high-salt diets with a 23% increased chance of obesity in schoolchildren. Those children may eat more because the salt makes the food taste good, the authors suggest. They also speculate that when they get thirsty after a salty meal, the children reach for easily available high-calorie sodas.
- Another Australian study from 2016 tied salt to an 11% rise in the amount of food and calories that adults take in. The researchers said salt improves flavor and likely tempts people to eat more.
"Studies show that eating a lot of sodium in our diet is linked with obesity," Beaver says. But it's not clear why. While these studies show a link between salt and body fat, overeating, and obesity, they don't show that salt makes those things happen by itself. More research is needed to fully understand salt's role.
Satiety hormones allow us to feel full after a meal. But the link between salt and weight may be because people who eat lots of salty foods also eat more calories overall, Beaver says. About 2 out of 3 adults are at risk for health problems from too much sodium. If you are one of them, it's a good idea to take steps to cut salt and calories by eating more whole foods and fewer packaged snacks.
How to Prevent Hypernatremia
The easiest way to prevent hypernatremia is to drink enough water and take in a reasonable amount of salt. But you normally won't get hypernatremia just from eating too many salty snacks or other high-sodium foods.
The average adult should drink four to six cups of water each day. If you're on certain medications, are very active, or live in a hot climate or at high altitude, you should drink more.
The American Heart Association (AHA) recommends no more than 2,300 milligrams of sodium a day (ideally less than 1,500 milligrams), especially if you have high blood pressure. However, the AHA says the average intake in the U.S. is more than 3,400 milligrams a day. That can lead to hypernatremia and other serious health problems.
Staying hydrated should help most people avoid hypernatremia. However, it may be the result of an electrolyte imbalance caused by other conditions. In this case, it could be a medical emergency and should be treated by doctors.
Takeaways
Hypernatremia happens when you have too much sodium in your bloodstream. It's more likely if you have certain health conditions or you're dehydrated. It's a good idea to limit the amount of salt in your diet. But you probably won't get hypernatremia from eating too much salty food, as your body naturally balances your amount of water and sodium.
Hypernatremia FAQs
What happens when sodium is low in the body?
This is hyponatremia. Usually, you recover fully, but in some cases, it can cause your brain to swell. Rarely, it can cause lasting damage.
How do you fix high sodium levels?
Adding more fluids is key. That's because your body maintains a balance between water and sodium. To get more fluid, it's best to drink enough water. That's because you don't want to reduce your sodium level too fast — that can cause seizures, brain swelling, or brain damage.
What's the prognosis for hypernatremia?
The outlook is good if you catch it early. Your body might even do this on its own by signaling you to drink more water and getting rid of more salt in your pee. But if you try to fix high sodium levels too fast, it may lead to long-term complications. See a doctor if you think you or a loved one may have hypernatremia.
What disease is associated with high sodium?
Many conditions can make your sodium too high. These include diabetes insipidus or kidney diseases. But it can happen to anyone if you get dehydrated or take in toxic levels of salt. It's more common in infants and older people.
Can hypernatremia be treated at home?
If your hypernatremia is mild, you may be able to fix it by drinking more water. But when hypernatremia is moderate or severe, it's important to see a doctor and make sure your imbalance of water and sodium is corrected safely.