Mild overhydration usually resolves on its own once you stop drinking fluids and let your body catch up. In most cases, you should start feeling better within a few hours. Severe overhydration, where sodium levels drop dangerously low, requires medical intervention and can take days to fully recover from.
Stop Drinking and Let Your Body Rebalance
The single most important step is also the simplest: stop drinking water. Your kidneys can excrete roughly 800 to 1,000 milliliters of fluid per hour, so if you’ve been overdrinking during exercise or throughout the day, pausing your intake gives your body time to flush the excess. For mild cases with no neurological symptoms like confusion or seizures, fluid restriction alone is often enough.
If you’re dealing with a more persistent issue (not just a one-time episode of drinking too much), the general clinical approach is to restrict fluids to about 500 milliliters below your 24-hour urine output. In practice, this often works out to roughly 1 liter per day. Studies on patients with chronic low sodium found that restricting to 1 liter daily raised sodium levels meaningfully within three days and maintained that improvement at 30 days.
Replace Lost Sodium
Overhydration dilutes the sodium in your blood, a condition called hyponatremia. Mild hyponatremia puts sodium between 130 and 135 milliequivalents per liter. Moderate falls between 125 and 130, and severe drops below 125. Even in the mild range, you can feel off: foggy, nauseated, or unusually fatigued.
Getting sodium back in is straightforward for mild cases. Salt your food generously. Salty snacks like pretzels, chicken noodle soup, tomato juice, and broth bouillon all help. If you’re recovering from exercise-related overhydration, dissolving 3 or 4 bouillon cubes in about half a cup of water creates a concentrated salty solution that works well. Sports drinks with electrolytes are better than plain water during this recovery period, since plain water would only dilute sodium further. Potassium-rich foods like bananas, oranges, and leafy greens also support electrolyte balance alongside sodium.
For athletes specifically, oral concentrated sodium solutions have been shown to work as effectively as intravenous treatment for mild cases. One study found that athletes who received oral treatment actually recovered faster and spent less time in the hospital than those given IV fluids.
Recognizing When It’s More Serious
Most people searching for how to fix overhydration are dealing with a mild situation: they drank too much water during a workout, felt bloated and slightly off, and want to know what to do. But overhydration can become genuinely dangerous, and it’s worth knowing where that line is.
Mild symptoms include nausea, bloating, headache, and a general feeling of being unwell. These typically clear within a few hours of stopping fluid intake. More concerning signs include vomiting, confusion, disorientation, and drowsiness that goes beyond normal tiredness. Seizures, difficulty breathing, and loss of consciousness indicate a medical emergency. At that point, the brain is swelling from excess water, and the situation can become life-threatening quickly.
If you or someone with you develops confusion, slurred speech, or seizures after heavy water intake, this needs emergency care. Hospital treatment for severe cases involves carefully administered concentrated saline solution to raise sodium levels. The key word is “carefully,” because correcting sodium too fast carries its own risk: a rare but serious condition called osmotic demyelination syndrome, which damages nerve cells in the brain. For patients with very low sodium (below 115), doctors aim to raise levels by less than 8 milliequivalents per liter in any 24-hour period.
Who Is Most at Risk
Endurance athletes are the most commonly affected group. Marathon runners, ultramarathon participants, and long-distance cyclists who drink large volumes of plain water over several hours without replacing electrolytes can develop exercise-associated hyponatremia. The combination of sweating out sodium and replacing it with sodium-free water creates the perfect storm for dilution.
People taking certain medications that affect how the kidneys handle water are also at higher risk. Some antidepressants, anti-seizure drugs, and pain medications can impair the body’s ability to excrete excess water. People with heart failure, liver disease, or kidney problems have a harder time maintaining fluid balance in general, making them more vulnerable to overhydration even from seemingly normal fluid intake.
Preventing It From Happening Again
The old advice to drink eight glasses of water a day regardless of circumstances has largely been replaced by a simpler guideline: drink when you’re thirsty. Your body’s thirst mechanism is remarkably well calibrated, and for most people in most situations, following it keeps you appropriately hydrated without overdoing it.
During exercise, use a sports drink with electrolytes rather than plain water, especially for activity lasting longer than an hour. Weigh yourself before and after long workouts. If you weigh more afterward, you drank more than you lost through sweat, which is a clear sign of overhydration. The goal is to roughly match fluid intake to fluid loss, not to exceed it.
If you’re exercising in hot conditions or acclimatizing to heat, salt your meals liberally in the days leading up to and following heavy activity. This builds a buffer of sodium that helps protect against dilution if you end up drinking more than usual.
Expected Recovery Timeline
For mild overhydration, most people feel noticeably better within a few hours of stopping fluid intake. The bloating, headache, and nausea fade as your kidneys do their job. Severe cases that require medical treatment can take a few days for full recovery, partly because sodium correction must happen gradually to protect the brain. During that time, fluid intake remains restricted and blood sodium is monitored closely to ensure levels rise at a safe pace.