Eating too much salt can have negative health impacts, but so can eating too little salt. While commonly discussed in relation to cardiovascular health, sodium intake affects more than just the heart.

Studies show that diets too high or low in salt can cause sleep disturbances. To help patients know when to put down or pick up the salt shaker, encourage them to think about individual factors that impact their body’s sodium needs—and to focus on balance rather than extremes.

Shrimanker I, Bhattarai S. Electrolytes. StatPearls [Internet]. July 24, 2023.

Li T, Song L, Li G, et al. Eating habit of adding salt to foods and incident sleep apnea: a prospective cohort study. Respir Res 24, 5 (2023). https://doi.org/10.1186/s12931-022-02300-6.

How salt intake affects sleep

Hypernatremia can produce symptoms like tachypnea, sleeping difficulty, and restlessness, and is diagnosed when someone’s serum sodium level is greater than 145 mmol/L.

Shrimanker I, Bhattarai S. Electrolytes. StatPearls [Internet]. July 24, 2023.

Perhaps surprisingly, not eating enough salt can lead to consequences like electrolyte imbalances, dehydration, and sleep issues. Deficient sodium intake can, at times, lead to hyponatremia, the opposite of hypernatremia. Hyponatremia can produce symptoms like headaches, confusion, nausea, and delirium, and is diagnosed when someone’s serum sodium level is less than 135 mmol/L.

Jaclyn Leong, DO, DABOM, a doctor in the integrative medicine and obesity medicine departments at UCI Health Susan Samueli Integrative Health Institute in Irvine, CA, says that if patients “are having symptoms of difficulty sleeping, associated with decreased REM and increased wakefulness, this could be a clue of salt depletion in their diet.”

What's the right amount?

Ideally, people should be eating some amount of salt between these two numbers. In reality, however, the FDA reports that most Americans consume, on average, about 3,400 milligrams of sodium per day.

Food and Drug Administration. Sodium in Your Diet. March 5, 2024.

Talking to patients about optimal sodium

Sodium needs vary among patients, and two people who are eating the same amount of dietary sodium may notice different health impacts. For instance, an athlete’s body may require large amounts of sodium to replenish what they lose from exercising and sweating. While this may be healthy for an athlete, a sedentary person who consumes the same amount of salt may notice health consequences. The same could be true the other way around.

"The optimal level of salt intake should be personalized for each patient," Dr. Leong says. “While low-salt diets are effective for blood pressure control, individuals with high activity levels or minimal comorbid conditions might be deficient if not consuming enough salt,” she explains. Sodium needs don’t just vary person to person, but also day to day. Changes can depend on the type of exercise someone is performing or how much rest they got the night before, she says.

To better understand if someone needs more salt in their diet, you can ask the following questions:

• Do you sweat during activities or exercise?

• Are you exposed to heat?

• Do you experience insomnia or reduced sleep?

• Do you have muscle cramping?

If the answer is “yes” to the above questions, and if the person maintains a high activity level, then they may need more salt in their diet. 

To better understand whether someone needs less salt in their diet, you can ask questions such as:

• Do you experience puffiness or bloating?

• Are your hands and feet swollen?

• Are you unusually thirsty?

• Do you get headaches?

• Do you consume mostly processed foods?

If the answer is “yes” to the above questions, then cutting back on salt could be a good idea.

In addition to assessing activity level, tracking sleep cycles and “clueing in on our daily intake is key to understanding if [we] are eating enough salt,” Dr. Leong says.

If a patient is unsure of their salt intake, you may suggest that they assess how much salt they are actually consuming. Some foods, such as frozen meals, packaged items, or restaurant meals, may have hidden sources of sodium. Reading nutrition labels or going old school and cooking at home—while also measuring salt that is added to food—are two suggestions for patients to stay more informed about their salt intake.

“The best way to measure salt is by preparing foods from fresh whole foods where you can add salt to the recommended daily value for your personalized health,” Dr. Leong says.