What is exertion?

Exertion is a metric, measured as a percentage, that combines each user's heart rate and core body temperature with individual characteristics such as height, weight, age, resting heart rate, and resting core body temperature.

• Below 70%: low or moderate exertion.
• Between 70% and 90%: high exertion, the user may need attention if this exertion rate is sustained for a long period of time.
• Above 90%: very high exertion, the user is in danger of overexertion.