Most people don’t think of salt when they think of hydration. They think of water fountains, water bottles, and other sources of plain fluids. Junior high health class wisdom like “drink eight glasses of water per day” might come to mind.
Meanwhile, those same folks might avoid salt for the belief that it’s dehydrating (along with many other misplaced fears about sodium). After all, if you demolish a bag of salty cashews, you’ll likely get thirsty.
Here’s the truth: As counterintuitive as it may seem at first glance, you need sodium to stay hydrated. Hydration is defined as maintaining fluid balance in the body. And sodium plays an integral role in holding this balance and helping fluids get where they need to go.
Want the “TLDR” for consuming enough sodium to stay hydrated? Drink to thirst (this’ll take care of the fluids), get 4–6 grams of sodium daily through diet and the salt shaker, and use an electrolyte drink to make up for any shortfalls.
If you have a few minutes to spare — or want some fun facts to share as you vigorously salt your food at the next family gathering — keep reading.
How Salt Influences Health and Hydration
About 60% of an adult’s weight is water molecules, and this water keeps your blood flowing, your sweat dripping, and your organs functioning. Sodium helps maintain this fluid balance on the cellular level, regulating the fluids outside of cells (potassium regulates the fluid inside).
If your sodium status isn’t optimal, your fluid balance won’t be optimal either. And since this delicate balance of water is essential, imbalances can have ripple effects across most areas of human health.
Sodium also affects health through a feature of animal biology called the sodium-potassium pump. The pump relies on sodium to power movement, thoughts, perceptions, and any other function that requires cellular communication (so, pretty much everything!).
When you don’t consume enough sodium, your fluid balance is thrown off and the sodium-potassium pump won’t function optimally. This can lead to symptoms of sodium deficiency that are often subtle and tricky to identify, like low energy, brain fog, headaches, and fatigue. Also tricky: Even if sodium intake is low, sodium levels on a blood test may look normal since the body will draw sodium from other sources (like bone) to compensate and keep blood levels stable.
Versus a sodium deficiency, a sodium imbalance occurs when blood sodium levels stray from normal ranges, often requiring medical attention. The main lifestyle driver of low blood sodium levels (called hyponatremia) is overhydration with plain water, which can dilute blood sodium levels and lead to (often severe) neurological symptoms. Exercise-associated hyponatremia is not uncommon in elite endurance athletes who drink plain fluids beyond thirst.
Let’s explore salt through the lens of dehydration now and answer a question the LMNT team fields often.
Does Salt Dehydrate You?
The short answer is no. Dehydration is net water loss from the body, and consuming salt does not cause this.
Just because salt can make you thirsty doesn’t mean it dehydrates you. Yes, if you rip through that bag of salty cashews, you’ll get parched due to rising sodium levels in the blood. This is because receptors detect this extra sodium and ping a brain region called the hypothalamus to activate the thirst mechanism. Then when you drink water, your sodium levels normalize, and your thirst dissipates.
Even if you don’t drink water, your kidneys will work to excrete the excess sodium. Your urine will get saltier, your sodium levels will creep back to normal, and your thirst will abate.
Of course, as with any compound, it’s possible to consume too much sodium. Excess sodium consumption can overwhelm your fluid balancing system, increasing fluid retention and elevating blood pressure.
But for folks eating a low-carb or whole foods diet, it’s harder to overconsume sodium than you might realize. The science shows that optimal health outcomes occur at 4–6 grams of sodium a day, which is a hard target to hit while eating unprocessed foods. And folks who sweat a lot or practice fasting may need even more. Sodium restriction also activates blood-pressure-raising hormones not ideal for heart health. As with anything, it’s about finding the right balance — and it’s clear that many health-conscious folks underconsume sodium and have more wiggle room to increase their intake than they realize.
Let’s talk about what influences salt needs now.
Factors That Increase Salt Needs
Dietary, lifestyle, environmental, and various health factors influence how much salt you need. This article plunges into these factors, but I’ll give a quick version here.
Dietary factors
Low-carb diets, fasting, and whole foods diets increase sodium needs for two main reasons:
- Consuming few carbs reduces the hormone insulin, causing higher sodium losses through urine
- Whole foods are naturally low in sodium (unlike ultra-processed foods like crackers)
Folks on these regimens must rely more heavily on the salt shaker and sources like LMNT to consume enough salt daily.
Lifestyle factors
Harder or longer workouts increase sweat loss and, therefore, sodium needs. Higher exercise intensities also raise sodium concentration in sweat, making sweat saltier and accelerating salt losses. For reference, athletes lose about 1 gram of sodium per liter of sweat on average. You can read our comprehensive guides on sweat rate and sweat sodium concentration to explore this topic further.
Environmental factors
Anything that increases sweating — higher ambient temperatures, higher humidity, reduced breeze, and warmer clothing — will increase salt needs. Altitude can either raise or lower salt requirements, depending on the situation. Read our winter hydration guide to dive deeper.
Conditions and other factors
Here’s a list of conditions and other factors that increase the need for salt:
- Pregnancy and breastfeeding
- Diarrhea, vomiting, or fever
- Postural orthostatic tachycardia syndrome (POTS)
- Orthostatic hypotension (OH)
- Gitelman syndrome
- Bartter syndrome
- Hyperhidrosis (excessive sweating)
- Night sweats
- Cystic fibrosis
- Ovarian hyperstimulation syndrome (OHSS)
Talk to your doctor if you have any of these conditions. Getting enough salt won’t “cure” these issues, but it can make management easier.
Getting Enough Salt for Hydration
This brings us back to the practical hydration tips we shared in the introduction. Drink to thirst (to simultaneously prevent overhydration and dehydration), consume 4–6 grams of sodium daily through diet and the salt shaker, and use an electrolyte drink to make up for any shortfalls.
The 4–6 grams figure may surprise you, but it comes from solid science on sodium and heart health. The FDA recommends limiting intake to roughly half that amount (2.3 grams of sodium daily), but this advice can do more harm than good. Our Sodium Intake Calculator can help you hone in on your specific needs.
To hit your sodium target, start by doing a dietary analysis. Use an app like Cronometer to log your daily food intake, including any salt from the shaker. The app will spit out your data, and you can adjust accordingly.
Don’t be surprised if you have trouble hitting your sodium goal. Like we touched on above, many folks on a whole foods diet don’t consume enough sodium through diet alone (or if they’re fasting, they don’t consume any).
Adding electrolytes to your water can help make up for any dietary shortfalls. A quick at-home solution is to mix half a teaspoon of salt with 16–32 oz of water (don’t forget a squeeze of lemon or lime for taste). LMNT also delivers 1 gram of sodium in their drink mix and Sparkling electrolyte water.
Follow these tips and you’ll stay happily hydrated — maintaining fluid balance, supporting the sodium-potassium pump, and helping your body feel and perform its best.
