Have you ever wondered about the readiness score on your smart watch? New to the latest Apple Watch 12 and the Ultra 4 and a long-standing feature in the Oura Ring, Fitbit, Garmin and Whoop, a readiness score is marketed as a measure of how prepared your body is to tackle your next workout.
Each company has their own proprietary formula for determining physiological readiness, but most wearables use a collection of data (sleep, exercise, heart rate) to build a score. Central to that calculation is heart rate variability.
One of the newest buzz words in fitness, HRV is the small slice of time between each heartbeat. Measured in milliseconds, a higher HRV is considered a sign of a healthy heart that responds well to situational stress, whether it be a workout, lifestyle stressor or a poor night’s sleep.
