Easy Endurance: Slow Running to Get Faster
You head out for a run, feel good, and speed up without noticing. What if your easy runs were actually easy? Here is what studies say about easy endurance, and how to set your pace.
The ELYO team
The sports coach that reads your workouts
The short answer
Easy endurance is the easy pace, below the first ventilatory threshold: you can talk without getting out of breath. In a 2026 randomized trial of 20 recreational marathoners, 82% or 75% of the time at that pace gave the same result (3:45 vs 3:46). To set it, combine how you feel with your heart rate: a max heart rate estimated by formula can be off by more than 10 bpm.
Key takeaways
- Easy endurance is an easy pace below the first ventilatory threshold. It is not the default "zone 2" on your watch.
- Among recreational runners, the 2026 marathon trial (20 runners) shows no difference between 82% and 75% of time in zone 1. Both plans had a large share of easy running in common.
- A max heart rate given by a formula can be off by more than 10 bpm. Check it against the talk test.
- Your best reference is the heart rate you see across several runs where you can talk easily.
You head out for a run, feel good, and speed up without noticing. The result: all your workouts feel the same, neither truly easy nor truly hard. Easy endurance does the opposite: you spend a large share of your running time at an easy pace.
But what counts as easy? The pages that explain it give heart rate ranges that contradict each other. Here is what the studies say, including what they don't prove.
Easy endurance, zone 2, easy pace: one term, several meanings
Easy endurance is the pace at which you can run for a long time without getting out of breath. In physiology, it sits below the first ventilatory threshold.
Watch the vocabulary. In this model, zone 2 sits around the lactate threshold: a clearly harder effort. The "zones 1 to 5" on your watch are divided differently, so your watch's "zone 2" doesn't necessarily match the researchers' zone 2. And 2 mmol/L is an average reference, not a threshold that works for everyone.
What the studies show: lots of easy, a bit of intensity
In well-trained and elite athletes, most studies describe a "pyramidal" distribution: a large volume at low intensity, less at moderate intensity, and even less at high intensity. Some world-class athletes adopt a "polarized" pattern at certain times: mostly easy running, a small amount of very hard effort, and almost nothing in between (Stöggl and Sperlich, 2015).
The 2025 meta-analysis by Rosenblat and colleagues pools 13 studies and 348 athletes, 150 of them recreational. It finds no difference between polarized and pyramidal training, either for VO2max or for time-trial performance. One subgroup suggests that competitive athletes may progress more with polarized training, and recreational athletes more with pyramidal training.
What stands out across all of this is the large share of easy running, not the exact split.
Among recreational runners: the 2026 marathon trial
The most recent trial looks at runners like you. In a 16-week randomized trial, 20 recreational marathoners followed one of two plans.
| Plan | Zone 1 | Zone 2 | Zone 3 | Marathon time |
|---|---|---|---|---|
| Polarized | 82% | 8% | 10% | 3:45 |
| Pyramidal | 75% | 22% | 3% | 3:46 |
The difference is not significant (p = 0.23), either on the simulated half marathon or on speeds at the thresholds. The 80/20 split is not a proven rule for recreational runners. What both groups share is most of their time in zone 1 (Esteve-Lanao et al., 2026).
Finding your right pace: feel first, then heart rate
The talk test
The official US reference for moderate intensity is simple: you can talk, but you can't sing (ODPHP, 2018). It is a rule of thumb, not a precise measure of a threshold. Coaches suggest using it as a safety check: if you can no longer say a full sentence without catching your breath, slow down.
Heart rate, without relying on a formula
Percentages of max heart rate assume a reliable max heart rate. The formula "220 minus your age" is not very reliable for an individual. In the HUNT study, which included 3,320 healthy adults, max heart rate follows roughly 211 − 0.64 × age, and older formulas underestimated measured max heart rate after age 30 (Nes et al., 2013).
What comes from the studies is the definition of easy pace based on the threshold. What comes from coaching practice are the max heart rate percentage ranges, which vary from one page to another: treat them as a starting point.
Free calculatorHeart rate zonesOpen the calculator →Running slowly is good for your health too
The recommendations are similar on both sides of the Atlantic: the WHO (2020) and the US guidelines (2018) both recommend at least 150 to 300 minutes per week of moderate-intensity aerobic activity (moderate to vigorous for the WHO) for adults.
No official rule covers easy endurance, however. It is a training concept, not a health standard. If an easy run causes pain or breathlessness that seems abnormal to you, talk to a doctor.
What you can do at your next workout
- Pick one run this week and run it at a pace where you can speak in full sentences.
- Slow down from the first kilometers: that's where most people start too fast without realizing it.
- Note your average heart rate and how you were talking, in one sentence.
- Repeat this on three or four runs to find your reference heart rate.
Keep some intensity too, like both groups in the marathon trial. To structure your week, see Improve your running with 3 runs a week. If you're aiming for a marathon, First marathon training: where to start covers the next steps.
To find your reference heart rate across several runs, ELYO reads your workouts from your watch and compares pace and heart rate from one run to the next. It then adjusts your training plan based on how you actually run.
Frequently asked questions
Is easy endurance the same as zone 2?
Not necessarily. In the researchers' three-zone model, easy endurance corresponds to zone 1, below the first ventilatory threshold. Research zone 2 is harder, and the "zone 2" on a watch does not always match either one.
What heart rate should I run at for easy endurance?
There is no official max heart rate percentage: the ranges on different websites contradict each other. Start with the talk test, then note your heart rate across several runs where you can talk easily. That personal value is more useful than a calculation based on your age.
Does the 80% slow, 20% fast approach work for recreational runners?
In the 2026 trial of 20 recreational marathoners, a plan with 82% zone 1 and a plan with 75% gave 3:45 and 3:46, with no significant difference. The 2025 meta-analysis also doesn't separate polarized from pyramidal training.
My heart rate climbs fast even when I jog, what should I do?
Your estimated max heart rate may be wrong: the error can exceed 10 bpm. Trust your breathing first: if you can talk easily, you are probably at the right pace. If the breathlessness seems abnormal or comes with other symptoms, talk to a doctor.
Sources
- Stöggl T., Sperlich B. (2015). The training intensity distribution among well-trained and elite endurance athletes. Frontiers in Physiology. DOI
- Rosenblat M. A. et al. (2025). Which Training Intensity Distribution Intervention will Produce the Greatest Improvements in Maximal Oxygen Uptake and Time-Trial Performance in Endurance Athletes? A Systematic Review and Network Meta-analysis of Individual Participant Data. Sports Medicine. DOI
- Esteve-Lanao J., Casado A., Arévalo-Chico H., Sellés-Pérez S., Cejuela R. (2026). Polarized vs pyramidal training intensity distribution in recreational marathoners: a randomized controlled study. International Journal of Sports Science & Coaching. DOI
- Nes B. M., Janszky I., Wisløff U., Støylen A., Karlsen T. (2013). Age-predicted maximal heart rate in healthy subjects: The HUNT Fitness Study. Scandinavian Journal of Medicine & Science in Sports. DOI
- U.S. Department of Health and Human Services, ODPHP (2018). Physical Activity Guidelines Questions & Answers, Physical Activity Guidelines for Americans, 2nd edition. Official page
- World Health Organization (2020). Every move counts towards better health, says WHO. Official page
Written with the help of AI.
