Garmin Metrics
Garmin Endurance Score vs Stamina vs VO2 Max: What Each Actually Tells You
March 9, 2026
Three Metrics, Three Different Questions
Garmin now gives you VO2 max, Endurance Score, and Stamina -- three metrics that all seem to measure "how fit you are for long efforts." Open your Garmin Connect app and you will find them scattered across different screens, with minimal explanation of how they differ or which one you should actually pay attention to.
Here is the short version: these three metrics answer fundamentally different questions about your fitness. VO2 max tells you how big your engine is. Endurance Score tells you how large your fuel tank is. Stamina tells you how much fuel you have left right now, mid-activity.
Understanding the distinction changes how you train.
VO2 Max: Your Engine Size
What It Measures
VO2 max is the maximum amount of oxygen your body can consume during intense exercise, expressed in milliliters per kilogram of body weight per minute (ml/kg/min). It is the gold standard metric for aerobic capacity and has been studied for decades.
Garmin estimates your VO2 max by analyzing the relationship between your running pace (or cycling power) and your heart rate during aerobic efforts. If you can run faster at the same heart rate, or run the same pace at a lower heart rate, your estimated VO2 max goes up.
For runners, a typical VO2 max range looks like this:
- Below 35: Beginner or untrained
- 35-45: Recreational runner
- 45-55: Competitive amateur
- 55-65: Highly trained
- 65+: Elite or near-elite
What It Does Not Tell You
VO2 max is a measure of your peak aerobic capacity. It tells you how fast your engine can rev. But it says nothing about how long you can sustain a high percentage of that capacity.
Two runners can have identical VO2 max values of 55 and have wildly different marathon times. The one who can sustain 80% of their VO2 max for three hours will crush the one who fades to 65% after 90 minutes. VO2 max does not capture that difference.
This is exactly the gap that Endurance Score was designed to fill.
How to Improve It
VO2 max responds best to high-intensity training -- intervals, tempo runs, threshold work. The classic VO2 max workout is 4-5 repeats of 3-5 minutes at 95-100% of max heart rate with equal recovery. These sessions push your cardiovascular system to its limit and force adaptation.
But there is a ceiling. VO2 max is partly genetic, and most athletes plateau after two to three years of consistent training. At that point, further improvements come from running economy and endurance capacity, not from a higher VO2 max. For a detailed guide on pushing your number higher, check out our complete guide to improving Garmin VO2 max.
Endurance Score: Your Fuel Tank
What It Measures
Endurance Score is Garmin's newest fitness metric, introduced in 2024. It quantifies your ability to sustain prolonged aerobic effort -- something VO2 max explicitly does not capture.
The score ranges from 0 to 100 and is calculated from your training history, specifically the volume and duration of your aerobic workouts over the past several months. It factors in:
- Total weekly training volume -- how many hours you spend training
- Long session frequency -- how often you do extended efforts (90+ minutes)
- Aerobic base depth -- the proportion of your training spent in lower heart rate zones
- Training consistency -- regular training over months scores higher than sporadic big weeks
An athlete who runs 30 miles per week with a weekly long run of 15 miles will have a higher Endurance Score than someone who runs 30 miles per week in short daily 5-milers, even if their VO2 max is identical.
Why It Matters
Endurance Score is the metric that best predicts how you will perform in events lasting longer than 60-90 minutes. A high VO2 max gets you a fast 5K. A high Endurance Score gets you through a marathon without falling apart.
Think of it this way: VO2 max is the horsepower of your engine. Endurance Score is the size of your gas tank and how efficiently your engine burns fuel at cruising speed.
For athletes focused on half marathons, marathons, ultramarathons, long-distance cycling, or triathlon, Endurance Score is arguably more important than VO2 max once you have reached a decent baseline aerobic capacity.
How to Improve It
Endurance Score responds to exactly the kind of training that does not move VO2 max:
- Long slow distance -- the weekly long run or ride is the single best driver of Endurance Score. Keep the effort in zone 2, keep the duration building gradually.
- Volume accumulation -- more total training hours per week, as long as you can recover from them. Consistency matters more than peak weeks.
- Double days -- two moderate sessions in a day accumulate more endurance-building stimulus than one longer session, for some athletes.
- Back-to-back long days -- running long on Saturday and moderate-long on Sunday builds the fatigue resistance that Endurance Score captures.
The catch is that Endurance Score moves slowly. It reflects months of training, not days. You will not see it jump after one big week. But over a 12-16 week training cycle, consistent long aerobic work will push it steadily upward.
Stamina: Your Real-Time Fuel Gauge
What It Measures
Stamina is different from the other two because it is a real-time, during-activity metric. Think of it as a battery indicator that depletes as you exercise and estimates how much effort you have left.
When you start an activity, your Stamina gauge shows two values:
- Potential Stamina -- the total effort your body can sustain before complete exhaustion, expressed as a percentage from 100% down to 0%
- Current Stamina -- your available effort right now, which drops as you push harder and partially recovers if you back off
The rate of depletion depends on your intensity relative to your thresholds. Running at zone 2 drains Stamina slowly. Running at threshold drains it much faster. Sprinting burns through it almost immediately.
How It Differs from Body Battery
This is a common source of confusion. Body Battery measures your general energy level throughout the day -- sleep, stress, activity all factor in. Stamina is purely an exercise metric. It only activates during a recorded activity and measures your remaining physiological capacity for that specific session.
Body Battery might say you have 85 points of energy when you start your run. Stamina tells you how that energy depletes and recovers during the run itself.
What It Is Good For
Stamina is most useful for pacing during races and long efforts. If you are running a marathon and your Stamina is at 30% at mile 15, you know you need to back off or you will hit the wall. If you are at 60% at mile 15, you have room to push.
Experienced athletes develop an intuitive sense of this, but Stamina gives beginners and intermediate athletes a real-time pacing tool that can prevent the most common racing mistake: going out too fast.
Can You Train It?
Not directly. Stamina is a reflection of your underlying fitness -- your VO2 max, your endurance capacity, and your metabolic efficiency. You do not train Stamina itself. You train the systems it measures, and Stamina improves as a consequence.
If your VO2 max goes up, your Stamina depletes more slowly at a given pace. If your Endurance Score goes up, your Stamina sustains better during long efforts. Stamina is the output. VO2 max and Endurance Score are the inputs.
Key Differences at a Glance
| VO2 Max | Endurance Score | Stamina | |
|---|---|---|---|
| What it measures | Peak aerobic capacity | Sustained effort ability | Real-time energy left |
| Score range | ~20-80 ml/kg/min | 0-100 | 0-100% |
| When it updates | After qualifying runs | Daily (based on history) | Live during activity |
| Time horizon | Last 4 weeks of data | Last 3-4 months | Current session only |
| Improves with | Intervals, tempo, threshold | Long slow distance, volume | Cannot train directly |
| Best predictor for | 5K-10K performance | Half marathon+ performance | Mid-race pacing |
| Available on | Most Garmin watches | Forerunner 265+, Fenix 7+ | Forerunner 255+, Fenix 7+ |
How the Three Metrics Work Together
The real power of these metrics is in combination, not isolation. Different combinations tell you different things about where you are and what you need:
High VO2 Max + Low Endurance Score
You are fast but cannot sustain it. Common in athletes who do a lot of intensity work but skip long runs. Your 5K is solid, but your marathon will be painful. Prescription: add more zone 2 volume and longer weekend sessions.
Low VO2 Max + High Endurance Score
You can go forever but not very fast. Classic ultrarunner or high-volume jogger profile. You have a huge aerobic base but your top-end fitness is underdeveloped. Prescription: add one to two intensity sessions per week -- intervals, hill repeats, or tempo runs.
High VO2 Max + High Endurance Score
The sweet spot. You have a powerful engine and a large fuel tank. This is the profile of a strong marathoner or an Ironman athlete who can both go fast and go long. Maintaining this requires a balanced training approach with both intensity and volume.
Both Low
You are early in your training journey, or you have been inconsistent. Focus on building an aerobic base with consistent, easy running before adding intensity. Three to four months of gradually increasing volume will move both numbers.
Which Metric Should You Focus On?
It depends entirely on your goal:
- Racing 5K or 10K? VO2 max is your primary metric. Endurance Score matters less at these distances.
- Training for a half or full marathon? Endurance Score is arguably more important than VO2 max. Prioritize it.
- Racing an ultra or Ironman? Endurance Score is everything. Your ability to sustain effort for hours is the whole game.
- General fitness with no specific race? Watch the balance between VO2 max and Endurance Score. A rising trend in both means your training is well-rounded.
Stamina is useful during events and long training sessions regardless of your goal distance. Add it to your watch data screens for any effort over 60 minutes.
If you want to track how all three metrics trend alongside your training load and workout history, Gneta pulls your Garmin data into a single dashboard where you can see the relationships over time. Understanding how changes in your training affect each metric is where the real insight lives.
The Bottom Line
VO2 max, Endurance Score, and Stamina are not redundant. They measure three distinct dimensions of aerobic fitness: peak capacity, sustained capacity, and real-time capacity. Confusing them leads to training that develops one quality at the expense of others.
Know which metric matters most for your goals. Train the systems that drive it. And use the others as a check on your overall fitness balance. The best endurance athletes do not just have one impressive number -- they have all three working in concert.
Related reading: