One of the most dangerous aspects of overhydration is that its symptoms can be confusingly similar to those of dehydration. A nephrologist explains this critical overlap and why it’s essential to consider context before reaching for another bottle of water.
Both severe dehydration and overhydration (hyponatremia) can cause symptoms like headache, nausea, vomiting, and fatigue. An athlete finishing a race might feel dizzy and unwell, but is it because they drank too little or too much?
This confusion is incredibly dangerous. If a person with hyponatremia mistakenly believes they are dehydrated, their instinct will be to drink more water. This action, while well-intentioned, is the worst possible thing to do, as it will further dilute their blood sodium and accelerate the medical crisis.
How can you tell the difference? Context is key. Did the person just run a marathon while sipping water at every station? Hyponatremia is a possibility. Has someone been working in the garden on a hot day without drinking anything? Dehydration is more likely. Another clue can be urine output; high output of clear urine suggests overhydration, while little to no output of dark urine points to dehydration.
Given the potential for confusion and the high stakes involved, if someone is experiencing severe symptoms like disorientation or seizures, it’s crucial to seek immediate medical help. Professionals can perform a blood test to determine the true cause and administer the correct treatment.