If you do a lot of riding in hot conditions, sweat testing may help you formulate your hydration strategy. There are two types of test: sweat rate and sweat composition.
“Sweat rate tests measure your sweat volume by calculating the difference between your pre and post ride weight, and are most reliable when conducted in the environment in which you plan to race,” says Dr Lewis James. “Sweat composition testing provides a rough idea whether your fluid and sodium losses are high, medium or low.”
That said, your sweat composition varies according to body sodium levels and hydration status – which is why James says it’s best to measure in race-relevant conditions.