WHOOP is designed for 24/7 use, but it is also designed for use by real people (i.e., circumstances will likely prevent 24/7 wear). We therefore built a system that is robust to reasonable periods of missing data, such as the duration of games in situations where league rules or athlete preferences prohibit in-game use. When a significant period of Strain is missing (such as competition or workout), WHOOP never attempts to guess or default the Strain, this missing data therefore introduces inaccuracies in two places for the day on which it takes place.
- The first is Day Strain – a user’s calculated Day Strain will be lower than his or her true physiological Strain on the day because they will get 0 credit for the period of time in which the strap was not worn.
- The second place is Sleep Coach – because of the low Day Strain, Sleep Coach will present a lower Sleep Need recommendation than what the user actually needs. Knowing this, an athlete may spend more time in bed proportionally to the day’s perceived strain.
The good news is WHOOP Recovery does not take Strain or Workout data as an input – it is simply not necessary because we can detect the down-stream impact of Strain on HRV and other Recovery metrics with the same accuracy and confidence level as if the athlete had never taken the strap off! This means that even though Day Strain and Sleep Coach were off on the day of the missed Strain, by the time the athlete wakes up the next morning, they are back to a fully-functioning system which is no worse for the missed data.