Why salt and fluids help
Every time you stand up, gravity pulls roughly half a liter of blood downward into your legs and abdomen. In most people the nervous system tightens those blood vessels within seconds, so blood pressure holds and the heart barely notices. In orthostatic intolerance — including POTS and the lightheadedness that leads to fainting — that automatic tightening is sluggish, so blood pools, less reaches the brain, and you feel it: lightheadedness, a pounding or racing heart, brain fog, or a near-faint.
You cannot easily fix the faulty vessel-tightening reflex. But you can give the system more blood to work with. Salt holds water in the bloodstream, and extra fluid raises the total volume. A fuller circulation pools less, so more blood stays available to push up to the brain when you stand. This is why salt and fluids are the very first thing we reach for — before any medication.
How much we aim for
For most patients with POTS or orthostatic intolerance, and assuming no reason they shouldn’t (see the caution below), we aim for:
- Salt: about 8–10 grams a day. That is well above a normal diet — roughly 3–4 teaspoons of table salt worth, spread across the day from food, added salt, and supplements.
- Fluid: about 2–3 liters a day. Water is fine; you do not need to drink only electrolyte drinks.
A few principles matter more than hitting an exact number:
- Ramp up gradually over a week or two rather than all at once. A sudden jump can cause bloating or, rarely, swelling.
- Spread it through the day. Sipping steadily beats drinking a liter at once.
- The morning bolus is powerful. Drinking a large glass — roughly 16 ounces (about half a liter) — of cool water within a few minutes of waking, before you get up and moving, blunts the morning symptoms many patients dread. It works partly through a reflex that briefly raises blood pressure.
Practical ways to hit the targets
- Salt your food generously, and lean into naturally salty foods: broth and bouillon, pickles and olives, salted nuts, cheese, canned soups.
- Salt tablets (often 1 gram each) make the target easy to reach without forcing salty food at every meal. We will tell you how many and when.
- Electrolyte and oral-rehydration drinks — sports drinks, electrolyte powders, or oral rehydration solution — deliver salt and fluid together and are handy before activity or on hot days. Watch the sugar in some sports drinks.
- Broth or bouillon is a comforting way to get a salt-and-fluid boost, especially in the morning or before exercise.
- Carry a water bottle and keep it visible. Most people undershoot fluids simply because they forget.
When salt-loading is not for you
This is important. Aggressive salt and fluids are the right move for orthostatic intolerance with a structurally normal heart — but they are the wrong move, and can be dangerous, for some patients:
- Heart failure — the heart may not handle the extra volume, which can worsen breathlessness and swelling.
- High blood pressure — extra salt can push it higher.
- Kidney disease — the kidneys may not clear the extra salt and water normally.
- Certain medications, including some used for blood pressure or the heart.
If any of those apply to you, do not start salt-loading on your own. We will look at your whole picture — heart function, blood pressure, kidneys, and medications — and tailor the targets, or choose a different approach entirely.
How this fits with the rest of the plan
Salt and fluids are the foundation, not the whole house. They work best stacked with:
- Compression garments — waist-high, 20–30 mmHg — to keep blood from pooling in the legs and abdomen.
- Graded recumbent exercise — reclined biking, rowing, or swimming to rebuild fitness without the upright posture that provokes symptoms. This is the single most evidence-based treatment for POTS.
- Medications when needed, such as midodrine or fludrocortisone, which we add on top of — not instead of — salt, fluids, and compression.
- Avoiding the things that make pooling worse: alcohol, hot showers and hot weather, large carbohydrate-heavy meals, and long periods of standing still.
When to check in with us
Tell us how you are responding — symptoms, and whether you notice any new swelling, shortness of breath, or weight gain (which would prompt us to dial the salt back). Bring your blood-pressure log if you keep one. Getting the salt-and-fluid foundation right, consistently, is what makes everything else we do work better.