Endurance runners currently have no method of measuring their hydration level whilst running long distances. While often over looked, over hydration is just as dangerous as dehydration, which is why it is crucial to understand for both health and efficiency. Hydra Templat calculates the runner’s on-run sweat rate and notifies the user how much water they have lost, depending on a pre-set value. As the user maintains a constant pace during their run, their sweat rate will also remain the same. Contained within the headband is a small device which measures the moisture content on the user’s forehead. Once calculated the data is sent to Hydra's app which notifies the runner-through sound or vibrations - of water lost during their run.