What is WHOOP Strain?
Strain measures the cardiovascular load that your body takes on during a given day or training session. Strain uses your physiological baselines to quantify how a given training stimulus taxes your body internally.
Strain uses a scale from 0 to 21. The closer to 21 you get, the more stress you put on your body.
How is Strain calculated?
Day Strain starts accumulating from the moment you fall asleep and resets every sleep cycle. Your Day Strain score represents the total stress load that your body takes on throughout the day, in and out of training and competition.
Activity Strain is calculated by combining the weighted time you spent in various heart rate zones throughout a training session. Periods of elevated heart rate and movement that are 15 minutes or more and qualify as at least an 8.0 Strain will be auto-detected and logged as an activity. If your activity included significant periods of rest and is not auto-detected, use Strain Coach to manually start and end the activity, or retroactively log the activity later.
How are Strain and Recovery related?
Strain takes your Recovery metrics, like resting heart rate, into account. This means that on days when your Recovery is low, you may fatigue quicker and Strain will accumulate easier. Monitoring Strain based on your Recovery can keep you performing at your peak recoverable volume for extended periods of time. Additionally, on days when you record levels of Strain that are higher than normal, monitor your score and pay close attention to your Recovery score.
Strain Coach recommends target exertion levels based on how recovered your body is. When you start an Activity, WHOOP shows you in real time whether you can push harder, you’re overdoing it, or you’ve reached your goal.
Strain scores in the gym
An intense lifting session may not register as high Strain, but don’t get discouraged. This does not mean that your body isn’t working hard. Anaerobic training will show up in other aspects of your physiological data like HRV and Recovery the following day.
The WHOOP Strap and the WHOOP Data Analysis Platform can help remove many of the mysteries of training. By monitoring our physiological response to cardiovascular load and recovery
efforts throughout the day, we can take decades-old training philosophy and meaningfully apply it
to better reach our goals and true physiological potential.
The training program produced improvements in change of direction skill, speed, anaerobic capacity, and muscular strength. Furthermore, all performance changes were maintained through the end of the study. Data from this study indicate that monitoring training load can give feedback to help augment performance and prevent performance decrements during the off-season.
Learn more about Strain
Our VPs of Performance and Data Science break down where WHOOP strain came from, how it works, what it measures, as well as all of the things that cause strain beyond exercise. They also discuss how to balance strain with recovery in relation to what your training goals are.