If you're cycling for 3 hours in cool weather and take 700 mg of sodium every hour, you'll drink about 160 mL more fluids each hour without feeling any thirstier, because the salt may trigger a natural urge to drink.

Endurance cyclists who take in 700 mg of sodium per hour during a 3-hour ride in cool weather tend to drink about 160 mL more fluid each hour than those who don’t — probably because the salt affects how thirsty they feel.

If trained cyclists drink when they're thirsty during a 3-hour ride in cool weather, they can keep their sodium levels safe — even if they don't take extra sodium.

If you drink a sports drink with 700 mg of sodium every hour while cycling 72 km in cool weather, your blood volume might go up a little bit because the salt pulls water into your bloodstream from your cells.

If elite cyclists drink as much as they want during a 3-hour ride in cool weather, taking in 700 mg of sodium per hour helps keep their blood fluid levels stable—or even slightly increases them—while skipping it leads to a small drop.

Taking sodium supplements during a long bike ride in cool weather doesn’t really change your body’s sodium levels if you're already drinking fluids whenever you feel like it.