Does more salt in your drink help when you sweat a lot?
A randomized, cross-over trial assessing effects of beverage sodium concentration on plasma sodium concentration and plasma volume during prolonged exercise in the heat
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Even with high fluid intake, low-sodium drinks caused blood volume to drop by 2%.
Most assume drinking plenty of fluid prevents dehydration, but this shows without enough sodium, your body can’t retain the fluid properly—defeating the purpose of hydration.
Practical Takeaways
If you're doing endurance exercise over 3 hours in hot weather, consider a sports drink with at least 60 mmol/L sodium to maintain blood volume and sodium levels.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Even with high fluid intake, low-sodium drinks caused blood volume to drop by 2%.
Most assume drinking plenty of fluid prevents dehydration, but this shows without enough sodium, your body can’t retain the fluid properly—defeating the purpose of hydration.
Practical Takeaways
If you're doing endurance exercise over 3 hours in hot weather, consider a sports drink with at least 60 mmol/L sodium to maintain blood volume and sodium levels.
Publication
Journal
European Journal of Applied Physiology
Year
2022
Authors
L. Wijering, J. Cotter, N. Rehrer
Related Content
Claims (5)
If fit guys bike hard in the heat and drink a lot, a sports drink with more sodium keeps their blood sodium steady, but one with less sodium causes it to drop a bit on average.
If fit guys sweat hard in the heat for about 3 hours and drink a lot of fluid, a sports drink with more salt (60 mmol/L) keeps their blood volume stable, but a low-salt version (21 mmol/L) causes their blood volume to drop by about 2%.
If fit guys sweat a lot for 3 hours in the heat and drink lots of fluid, a sports drink with more salt (60 mmol/L) helps keep their blood sodium up, while a low-salt version (21 mmol/L) causes it to drop — and the difference is clear.
When fit guys bike for 3 hours in the heat and drink about a liter of fluid per hour, they lose a little body weight — around half a percent. They might lose slightly less if their drink has more salt, but the difference isn’t strong enough to be sure it’s not just chance.
Taking electrolytes like sodium helps you perform better and stay safer during long workouts—like marathons or cycling races—that last over four hours, especially when it's hot outside.