Suffer Score on Strava: What It Is and How to Use It to Train Better
If you use Strava regularly, you've probably noticed that number that appears at the end of each activity: the Suffer Score. Sometimes it's 12. Other times, after a hard race, it shoots up to 280. But what does it actually mean? Is a high Suffer Score a good thing? Should you chase it or avoid it?
In this article I'll explain what the Suffer Score measures, how Strava calculates it, and most importantly: how to use it to make better training decisions.
What Is Strava's Suffer Score
The Suffer Score is a metric Strava developed to quantify the cardiovascular effort of an activity. It doesn't measure distance, speed, or watts. It measures how much time you spent in each heart rate zone during the workout and assigns a weight to each zone.
The logic is simple: running 1 hour in zone 1 (easy jog) is not the same as running 1 hour in zone 4 (threshold). The impact on your body is radically different. The Suffer Score tries to capture that difference.
To calculate it, Strava needs recorded heart rate data. Without a heart rate sensor, there's no Suffer Score.
How Strava Calculates the Suffer Score
Strava divides your heart rate into five zones based on your maximum heart rate. Each zone is assigned a points-per-minute multiplier:
| Zone | % Max HR | Name | Points per minute |
|---|---|---|---|
| Zone 1 | 50–60% | Active recovery | ~0 |
| Zone 2 | 60–70% | Base aerobic | ~1 |
| Zone 3 | 70–80% | Aerobic | ~2 |
| Zone 4 | 80–90% | Threshold | ~4 |
| Zone 5 | 90–100% | Anaerobic | ~7 |
The result is the weighted sum of all those minutes. A 1-hour session entirely in zone 2 might yield a Suffer Score of 60. A 45-minute session with zone 5 intervals can exceed 200.
What a High or Low Suffer Score Means
Here's the most common mistake: thinking a high Suffer Score is always better. It's not.
A high Suffer Score means your cardiovascular system worked hard and for a long time at high intensities. That does create adaptations. But it also generates accumulated fatigue that requires recovery.
A low Suffer Score doesn't mean you trained poorly. A 90-minute easy run in zone 2 might have a Suffer Score of 40, but it's doing exactly what it's supposed to: building aerobic base, improving mitochondrial efficiency, and allowing the central nervous system to recover.
The key isn't to maximize your Suffer Score every session. The key is for the distribution of your Suffer Scores throughout the week to be consistent with your goal and your recovery level.
How to Use the Suffer Score to Manage Your Training Load
The Suffer Score becomes really useful when you stop looking at it session by session and start analyzing it as a weekly trend. Here are the most practical ways to use it:
1. Track your total weekly load
Add up the Suffer Scores for the whole week. If your week typically totals between 300 and 400 points and suddenly you hit 700, you've tripled the load. That rarely ends well. A sustainable week-over-week increase is between 5% and 10%.
2. Detect if you're accumulating too much intensity
Si la mayoría de tus puntos vienen de sesiones con Suffer Score >150, estás entrenando constantemente en zonas altas. El modelo 80/20 —popularizado por la investigación sobre entrenamiento polarizado— sugiere que el 80% del volumen debería estar en zonas bajas. Revisa si tus sesiones suaves de verdad lo son.
3. Use it to plan recovery
Después de una sesión con Suffer Score >200 (competición, serie larga de intervalos, tirada larga), necesitas al menos 24-48h de recuperación activa antes de volver a cargar. El número te da un criterio objetivo frente a la subjetividad de «me encuentro bien».
4. Compare sessions of the same type
If you run the same route every week and your Suffer Score drops from 120 to 90 at the same pace, that's a sign of improvement: your heart is working less for the same external effort. You're improving cardiovascular efficiency.
Suffer Score Limitations You Should Know
The Suffer Score is a useful tool but has important limitations you need to understand to avoid misinterpreting it:
- It only measures cardiovascular load. It doesn't capture muscular stress (which is crucial in trail running, strength cycling, or technical swimming). An intense weight training session generates no Suffer Score even if it destroys your legs.
- It depends on the accuracy of your max HR. If Strava has your maximum heart rate set incorrectly, the zones will be off and the Suffer Score will be wrong. Check your profile.
- It doesn't account for stress outside of sport. A week of poor sleep, intense work, or personal stress reduces your ability to absorb training load even if the Suffer Score is the same as always.
- It doesn't distinguish training quality. Two sessions with a Suffer Score of 100 can be radically different in terms of the adaptations they generate.
Suffer Score vs. Other Load Metrics
The Suffer Score isn't alone. There are other metrics that measure similar concepts with varying depth:
- TSS (Training Stress Score): Used on platforms like TrainingPeaks, it combines duration and intensity relative to threshold. More precise for cyclists with a power meter.
- TRIMP (Training Impulse): The original scientific concept from which many of these metrics are derived.
- Garmin Training Load: Similar to the Suffer Score but with its own proprietary algorithm.
The Suffer Score has the advantage of being accessible to any athlete with a heart rate monitor, without needing a power meter or an advanced subscription.
Summary: What to Remember About the Suffer Score
- It measures the cardiovascular impact of a workout, not its quality.
- It's calculated based on time spent in each HR zone.
- A high number isn't inherently better: it depends on what type of session it was.
- It's more useful as a weekly trend than as an isolated data point from each session.
- It complements other metrics but doesn't replace them.
The problem with the Suffer Score — like almost all Strava metrics — is that it gives you the data but doesn't tell you what to do with it. You see the 180 after your Sunday race and don't know if that means you should rest tomorrow, maintain the load, or reduce it.
Iron Buddy connects your Strava data and analyzes not just the Suffer Score of each session, but the load trend over recent weeks, your recovery pattern, and your upcoming goal. The result is a concrete analysis: whether you can push harder this week, whether you need to ease off, and what type of session makes the most sense tomorrow based on what your actual history says.
Connect your Strava and discover what your data is really telling you about your training.