The news desk
On October 2, 2026, Runners Connect Science Training published an article introducing how runners can calculate their sweat rate and plan hydration. The article states that runners sweat on average about 1.3 liters per hour, with individual variation ranging from 0.2 liters to 5.0 liters. The calculation method is the difference in body weight before and after running plus the amount consumed during the run: first urinate, weigh your net weight, run for 60 minutes at target pace and record the amount you drink, dry off and weigh again; each 1 kilogram of body weight lost is roughly equal to 1 liter of sweat. The article recommends that for races longer than 60 minutes, drink between half and the full amount of your sweat rate, and do not exceed your own sweat rate; finishing heavier than at the start is a warning sign of hyponatremia.
Runners lose about 1.3 liters of sweat per hour on average, but individual rates range from 0.2 to 5.0 liters. Calculate yours by weighing before and after a 60-minute run and adding back what you drank: every kilogram lost equals 1 liter of sweat. For runs over 60 minutes, drink between half and your full sweat rate, never more. Finishing heavier than you started warns of hyponatremia.