Garmin Endurance Score

Plain English: Garmin’s long-term rating of how well an athlete can keep going over long efforts. It starts from aerobic fitness and adds credit for the volume and length of the last few months of training. A higher number means the athlete can hold an effort for longer, while a lower one means fitness or long training has fallen away.

In practice: This is a harmless, fun metric. In my experience, it is over-generous and flattering. I don’t trust it.

Quick answers

What is a good Endurance Score on Garmin?
Garmin rates the score in seven bands from Recreational to Elite, adjusted for age and sex. For men aged 21 to 39, Elite starts at 8,800, and for women of the same age it starts at 7,300. Garmin told DC Rainmaker that professional Ironman athletes score around 11,000.

How does Garmin calculate Endurance Score?
Garmin starts from VO2 max and adds training history from the last 2 to 3 months and the most recent 2 weeks, giving the longest activities special consideration. Only activities recorded with heart rate count. Garmin does not publish the model or the weight each sport carries.

How do I improve my Garmin Endurance Score?
Raising VO2 max lifts the starting point, and regular long sessions over two to three months add the fatigue resistance the score credits. Garmin says the score best reflects the activities an athlete does most, so hours in the main sport help more than the same hours spread across several.

What is the difference between Endurance Score and Real-Time Stamina?
Garmin treats them as separate features. Endurance Score is a long-term rating built from months of activities with heart rate, while Real-Time Stamina estimates how much an athlete has left during an activity. Stamina Zones, on Enduro 4 and Fenix 9, appear inside the Endurance Score glance.

Endurance Score – a deep dive

When Endurance Score is actually useful

This is only useful for individual athletes tracking progress over time. An improved endurance score likely reflects a real improvement in endurance. However, the score shouldn’t be compared to others.

Introduction

Garmin Endurance Score combines aerobic fitness and fatigue resistance to estimate an athlete’s ability to sustain performance over time. The owner’s manual adds that it is based on all recorded activities with heart rate data, so runs, rides, swims and other sports all count towards one points score with a rating from Recreational to Elite. Garmin announced it in May 2023 with Fenix 7 Pro and Epix Pro (Gen 2), alongside Hill Score.

The score builds on VO2 max, which Garmin calls the starting point of the calculation, and adds the recent training history that also drives Training Load. Its main limitation is that no study has validated the composite score, so the rating bands rest on Garmin’s own Human Performance Lab rather than on published research.

What Endurance Score actually means

A higher score means an athlete can sustain effort for longer, and a falling score means aerobic fitness or long training has slipped. Garmin rates the number in seven bands (Recreational, Intermediate, Trained, Well Trained, Expert, Superior and Elite) and adjusts them for age and sex, stating that “These estimates are provided and supported by Garmin Human Performance Lab.” The table gives the bands for men and women aged 21 to 39, and Garmin publishes bands for every age group in the owner’s manual. Garmin told DC Rainmaker there is no hard upper limit, with professional Ironman athletes scoring around 11,000 and scores beyond 12,000 unlikely.

Source: Garmin’s Endurance Score ratings appendix; the gaps between bands are Garmin’s own wording.

How Garmin calculates Endurance Score

Garmin states that aerobic fitness, measured as VO2 max, “provides the starting point for calculating your endurance score.” When there is no recent VO2 max, “the analytics engine estimates your current aerobic fitness based on a combination of your age, gender, BMI and recent activity levels.” Training history enters through two windows: “The longer-term perspective considers between 2 to 3 months of data, while the shorter-term perspective is limited to the most recent 2 weeks.” Garmin adds that “your longest activities carry special consideration”, reflecting fatigue-resistance adaptations it describes as metabolic, neural and muscular.

Garmin does not publish the model. DC Rainmaker’s account from the launch is that the score looks at overall activity duration together with intensity, measured relative to VO2 max, which is the most plausible reading of how training enters it. The origin of the points scale and the weight each sport carries are unknown. Activities recorded without heart rate do not count. At launch, the first calculation drew on 30 days of history, though that 2023 behaviour may have changed since.

What affects the reading

Sport has the largest effect. Garmin says the score best reflects the activities an athlete does most and that “Endurance doesn’t transfer perfectly from one activity type to another”, so the number describes endurance in the main sports rather than in general.

The VO2 max estimate is the starting point, so anything that skews it, such as poor heart rate data, moves the score as well. Cycling VO2 max from a power meter feeds in alongside running VO2 max. Because Garmin gives the longest activities special consideration, a block of training without long sessions is likely to pull the score down even when short sessions continue.

How accurate is Garmin Endurance Score

No study has validated Endurance Score as a composite, and Garmin publishes no error figure for it. Its main input has independent evidence: Carrier and colleagues (Sensors, 2025) found a mean absolute percentage error of 7.05% for Fenix 6 VO2 max estimates, so the starting point can be several per cent out before any training history is added.

The trend over weeks is more useful than the absolute number or the band, since the same watch and the same input errors apply to every reading. the5krunner’s first-hand take, Garmin calls me Elite, argues that the composite is “made up” and unvalidated, and that the Elite label is both misleading and motivating.

Competitor equivalents

• Polar has no direct equivalent, and its closest metric, Running Index, is a single-session score rated in age and sex bands.
• Apple has no equivalent, because Cardio Fitness reports VO2 max only.
• COROS Running Fitness is the closest analogue, a 40 to 100 score built from Base, Endurance, Speed and Sprint over six weeks of pace and heart rate data, with no age or sex bands.
• Suunto has no equivalent, because its Fitness level is a VO2 max estimate shown in eight bands.

Which Garmin devices support Endurance Score

Garmin introduced Endurance Score in May 2023 on Fenix 7 Pro and Epix Pro (Gen 2), and the Q3 2023 update added it to Forerunner 955, Forerunner 965, Fenix 7 and Epix (Gen 2). As of November 2026, Garmin’s owner’s manuals also list it for Forerunner 945 LTE, Forerunner 970, Fenix 8 series (including Fenix 8 Pro), Fenix 9 series (including Fenix 9 Pro), Fenix E, Enduro 3, Enduro 4, D2 Mach 2, D2 Mach 2 Pro, Venu X1, Descent Mk3, MARQ (Gen 2), Quatix 8, Tactix 7 and Tactix 8. Support on lower-priced ranges varies, and the owner’s manual for each watch confirms it.

Where to find Endurance Score on Garmin

• Watch glance: the score, its rating from Recreational to Elite, a graph over time and the activity types contributing most. Add it by swiping up, then choosing Edit, Add and Endurance Score.
• Stamina Zones: on Enduro 4 and Fenix 9 only, shown inside the Endurance Score glance.
• Garmin Connect: the score and its history in the performance stats.

Common problems and misreadings

A short session can move the score more than a long one. DC Rainmaker recorded a two-hour hilly trail run that moved his score from 8,075 to 8,077, while a 30-minute easy swim afterwards lifted it to 8,114. Garmin does not publish the weighting by sport, so the reason is unknown.

The Elite label surprises athletes who do not race at elite level. The bands compare the score with others of the same age and sex, as set by Garmin’s Human Performance Lab, rather than with competitive standing.

Endurance Score, Real-Time Stamina and Stamina Zones are separate features, which Garmin’s own support FAQ sets out side by side. See Quick answers above.

How to improve Endurance Score

The score responds to both of its inputs. Raising VO2 max lifts the starting point, and regular long sessions add the fatigue resistance Garmin credits through the special weight it gives the longest activities. The longer-term window covers 2 to 3 months, so consistent training across that period helps more than one big week.

Which sport the hours go into counts as much as how many there are. Because endurance does not transfer perfectly between activity types, time in an athlete’s main sport counts for more than the same time spread across several.

Scientific basis

Joyner MJ, Coyle EF. Journal of Physiology, 2008. PMID 17901124. VO2 max, lactate threshold and efficiency together set sustainable performance, which is the logic behind starting from VO2 max and adding other factors.

Maunder E, Seiler S, Mildenhall MJ, Kilding AE, Plews DJ. Sports Medicine, 2021. PMID 33886100. The paper defines durability as resistance to fatigue during prolonged exercise, the second component Garmin says the score adds to VO2 max.

How Endurance Score connects to other Garmin features

Endurance Score starts from VO2 max and draws on the same activity history as Training Load. Real-Time Stamina is a separate in-activity estimate, and Stamina Zones on Enduro 4 and Fenix 9 sit inside the Endurance Score glance. Hill Score arrived on the same watches as Endurance Score, and Race Predictor sits beside both among Garmin’s performance metrics.