How to build your sodium protocol for endurance running

Zach Bitter drinking from a water bottle beside the headline "Sodium Protocol for Endurance Running".

Fall is coming, which means marathon training is ramping up. High mileage plus high temperatures means your sodium needs probably ramp up, too.

Sodium helps you maintain blood volume. Lose too much sodium without replacing it, and blood volume falls. Your heart works harder. Cooling becomes less efficient. You run the risk of nausea and GI distress.

And it doesn't take extreme dehydration for performance to suffer: Losing just 2% of your body weight in fluid can impair endurance performance. To put that in perspective, marathoners lose an average of 2.3% of their body weight during a race.

Of course, sodium losses (and therefore needs) vary from person to person. There's no one-size-fits-all prescription, but running coach Bailey Lasko and LMNT partner Zach Bitter recommend using this sodium protocol as a starting point:

Start with a baseline. About 500 mg of electrolytes per hour (half a stick pack of LMNT) in normal conditions, increasing to about 900 mg (a full stick pack) for hotter or longer efforts.

Estimate your sweat losses. Weigh yourself before and after an hour of training without drinking anything. One kilogram (2.2 lb) of weight loss is roughly equal to one liter of fluid lost.