Here’s a sweat rate calculator to help you master your hydration game

Have you ever wondered exactly how much fluid you’re losing from sweat when you run? You’ve probably noticed you sweat at a different rate than your running buddies, but it can be tough to know how to hydrate to your specific needs. Enter the Sweat Loss Prediction Calculator, a new tool designed by researchers in Australia that aims to help athletes calculate their expected whole-body sweat rate.

Developed through extensive research conducted across two sites in Australia, this calculator is based on data from 182 outdoor running trials and 158 outdoor cycling trials. The aim was to test sweat rate prediction equations to help athletes during moderate to high-intensity outdoor activities, using monitored activities and environmental conditions.

How it works

The sweat loss calculator uses a prediction model developed from data gathered throughout the exercise trials. Participants’ whole-body sweat rates were measured over 60-minute sessions, with environmental conditions like temperature, wind speed and humidity recorded. These conditions were also rated subjectively by the participants.

Interestingly, the models worked well even when subjective environmental assessments were used instead of precise measurements. For runners, substituting subjective data slightly decreased the model’s accuracy (by less than 25 per cent), while for cyclists, the decrease was minimal, at around two per cent.

Practical benefits for athletes

With this calculator, available here, runners and cyclists can tailor their hydration strategies to their specific needs. The models offer 95 per cent confidence intervals that are within acceptable limits for maintaining body mass over a three-hour period, which is crucial for endurance athletes. By punching in simple activity details and your expected environmental conditions, you’ll receive personalized hydration advice, helping you stay hydrated and perform at your best, no matter the weather conditions.