28 - Tracking your activityUnderstanding how your body uses these two systems allows you toperform better in endurance exercises.Estimating StaminaThe Stamina rating is based on information in yourprofile, such as gender, age, height and weight, withadditional reference to daily step and heart ratemeasurements. While you are exercising, the greenborder around the Leap Ware screen indicates yourcurrent Stamina - a full green arc means your Stamina is at 100% andas your Stamina is used, the arc will gradually disappear.UV meterWhat is the UV meter?The UV meter detects theintensity of ambient ultraviolet(UV) light. Prolonged exposurecan damage your skin.Estimating UVThe UV meter uses photodiodes to estimate ambient UV light. Thisadjusts automatically to differentiate between indoor or outdoorlighting.Detected UV levels are rated from Low to Extreme, rated from one tofive sun icons. As the rating increases, take more precautions toprotect yourself from the sun’s rays, such as using sunscreen orstaying in shade, especially in the middle of the day.1:123010.19kmbpm15422:40NoteDo not block the meter (above the touchscreen) while it is active. The metermust be in direct sunlight and point towards the sun.