Why drinking too much water can be dangerous during long races
Hyponatremia in distance runners: fluid and sodium balance during exercise.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Drinking too much water, not losing salt, is the primary cause of dangerous low sodium in endurance athletes.
Most people assume dehydration and salt loss are the biggest risks during long exercise, so the idea that overhydration is more dangerous contradicts decades of sports messaging.
Practical Takeaways
Avoid drinking excessive fluids during endurance events lasting more than 4 hours; listen to your thirst instead of forcing fluids.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Drinking too much water, not losing salt, is the primary cause of dangerous low sodium in endurance athletes.
Most people assume dehydration and salt loss are the biggest risks during long exercise, so the idea that overhydration is more dangerous contradicts decades of sports messaging.
Practical Takeaways
Avoid drinking excessive fluids during endurance events lasting more than 4 hours; listen to your thirst instead of forcing fluids.
Publication
Journal
Current sports medicine reports
Year
2002
Authors
T. Noakes
Related Content
Claims (4)
When people exercise a lot, they can get low sodium because they drink too much water, not because they aren’t taking in or losing too much salt.
If endurance runners drink too much during long races, it can dilute their blood and cause dangerous low sodium levels — not just from losing salt, but from drinking too much. Cutting back on fluids in events over 4 hours could prevent this problem.
Telling athletes to drink as much as they can during long workouts might actually be causing more cases of dangerous low sodium, not preventing them.
You won’t get low sodium symptoms from sweating during long workouts unless you drink way too much water — so replacing sodium isn’t the most important thing to prevent this issue.