If fit guys cut down on salt for 9 days, they pee out less sodium—even when exercising in the heat—showing their bodies are adjusting and they’re sticking to the low-salt plan.

If you eat a lot of salt—like 18 grams a day for 10 days—your body will flush out more salt in your urine and also have a bit more salt in your blood, which proves you actually ate the salty food they gave you.

If endurance-trained guys eat less salt for 9 days, their blood sodium drops — even if they drink enough water — especially when they bike in the heat. This suggests long-term salt intake might affect how their body handles hydration in hot weather.

If you eat a lot of salt—like 18 grams a day for 10 days—your body will pee out more salt and your blood will have a bit more salt too, which proves your body is responding as expected to the extra salt.

If fit guys eat a low-salt diet for 9 days, their bodies heat up more and their hearts beat faster when they bike in the heat — even if they drink the same amount of fluids — suggesting their bodies aren’t cooling as well.

When people who don’t get high blood pressure from salt eat more or less salt, their kidneys adjust how much salt they pee out—no matter if they’re male or female.