Understanding how WHOOP 5.0 and MG measures strain (updated for 2025)
Strain, awarded on a scale from 0.0 to 21.0, is one of WHOOP's most misunderstood metrics—especially for newcomers. Many wonder: why do two activities each with a strain of 5.0 lead to a day strain under 10.0? How much effort is needed to hit my daily target? Let’s break it down.
Strain progression isn’t linear
As strain increases—whether in a single activity or over the course of a day—it becomes exponentially harder to gain more. In simpler terms, the higher your strain, the more effort it takes to keep it climbing.
To make comparisons between activities fair, WHOOP resets the strain scale to zero for each activity. This ensures consistency. For example, if you record a workout in the morning with 10.0 strain and repeat the same workout later, the second effort will still show as 10.0 strain rather than a reduced score due to accumulated fatigue. The downside? The math gets tricky when combining multiple activities into a single day strain. Two 10.0 strain workouts don’t equal a day strain of 20.0—and that’s by design. Even as separate activities, each was a 10.0 effort. If combined into one session, they wouldn’t add up to 20.0 either.
Day strain resets at midnight
Another factor to consider is that day strain resets every night at midnight. For workouts that span midnight, the strain is split across two days, contributing to both day strains but only one activity strain.
Visualizing strain progression
To better understand how strain accumulates, take a look at the graph below—based on estimates from Reddit user u/Jjpeters10 (credit goes to them!). The graph illustrates how much effort (a relative measure) is needed to reach certain strain levels:
Key Insights:
- Reaching 5.0 strain requires minimal effort—this explains why waking up with a strain closer to 5.0 than 0.0 is common.
- Going from 5.0 to 10.0 strain takes about 3x the effort, and another 3x that effort pushes you to 15.0.
- Approaching the maximum strain of 21.0 requires roughly 10x the effort of reaching 10.0 (and likely even more as the curve flattens).
For example, if it takes 30 minutes of running to hit 10.0 strain, you’d need about an hour to reach 13.2 strain and 90 minutes to hit 15.0—assuming a consistent intensity. Remember, the effort values are relative: what feels like a 50 on this scale may differ from person to person. However, they show that 50 is five times harder than 10, and 100 is twice as hard as 50.
Pushing the limits: high strain in practice
What does it take to hit the upper limits of the strain scale? After tracking 1,150+ days on WHOOP, I’ve only recorded a day strain of 20.0 or higher 30 times—just 2% of my total days. My highest day strain is 20.7, achieved five times in three years.
For context, professional cyclist Lachlan Morton recorded a 20.8 strain after biking 565km (351 miles) and climbing 3,833m (12,575ft) in one day during his alternative Tour de France. If you’ve hit a 20.8 or higher, let me know—I’d love to add you to this elite club!
Track and pptimize your strain with fitIQ
fitIQ offers tools to visualize your training metrics, including day and activity strain. You can set weekly, monthly, or yearly strain goals, track personal achievements, and even set a maximum strain target to hit once in a given period. I’m currently chasing a single 20.8 this year—it’s been quite the challenge!
fitIQ also offers strain-related streaks and badges to keep you motivated. It’s free to try and reasonably priced if you want to dive deeper. Give it a shot and take control of your strain tracking today!
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