Knowledge Hub · Heart rate and zones
What's the Best Way to Set Your Heart Rate Zones?
Photo: Ben Creswick, IRONMAN 70.3 Victoria
Your heart rate zones decide how hard every easy day really is. So where do yours come from?
The best heart rate zones are built on top of your power and pace, not guessed from your age or a single test. Set Critical Power on the bike and Critical Speed on the run and swim first, then find the heart rate that matches your easy output. That is how ANC does it, and it changes how every session feels.
The short answer
- Age formulas are a starting guess, and they can be wrong for you by a lot.
- Race estimates are better, but conditions on the day shape them.
- Structured field tests are where ANC anchors your zones.
- Lab testing is the gold standard for thresholds, and it costs more and happens less often.
- Heart rate zones come last, built from your power and pace.
Know why your zones matter
Your zones are the instructions behind every session. If they are off, your easy days drift too hard or stay too easy, and you may never notice.
That is why the method matters more than the number on your watch. Here are the four common ways to set zones, from least to most accurate.
Question the age formula
220 minus age is quick and free, and it is often the default on a new watch. Newer athletes and people who never change their watch settings tend to train on it without knowing.
A 2026 survey of 4,375 endurance athletes found that 220 minus age guessed max heart rate about 6 beats low on average [1]. For individuals, the miss ran from about 20 beats too low to 9 too high. A formula can be close on average and still be wrong for you.
Use race estimates with care
Estimating zones from a 5K or another race is a real step up. The number comes from your own body at a true effort.
The catch is everything else that happened that day. Pacing, heat, terrain and how fresh you were all move your heart rate, so one race can push your zones in the wrong direction.
At ANC we do use race data, in a specific way. Your average heart rate from a race maps to the top of a zone, not the middle of it.
Anchor your zones to a field test
This is where ANC builds your zones. Critical Power on the bike and Critical Speed on the run and swim measure sustainable output directly, so they are the main anchors.
Heart rate comes second because so much moves it. Heat, hydration, fatigue, stress, drift and lag all change it from day to day, even when your fitness has not changed.
A standalone heart rate field test is actually the least accurate field method. Heart rate is most useful once it sits on top of a solid power or pace anchor.
Know when the lab is worth it
Lab testing with blood lactate or breath gas analysis is the gold standard for finding thresholds. It is precise and it is useful.
It also costs more and happens less often, and your fitness keeps moving between visits. A 2026 treadmill study of 1,411 runners found that heart rate at the first threshold varied by sex and fitness [2]. Individual testing beats any one size rule, and field tests let you repeat it as often as your training needs.
How ANC sets your zones
Here is the order we follow. Power and pace first, heart rate on top.
The ANC plan
- Bike: maximal efforts of 3, 6 and 12 minutes. We model Critical Power and W' from those plus your recent power history.
- Run: several efforts above Critical Speed, such as 400 m, 800 m and 3200 m. We model Critical Speed and D' from those plus your training history.
- Swim: efforts of 100, 300 and 600 yards.
- Heart rate: once your power and pace zones are set, hold a steady 40 to 60 minutes at Zone 1 power or pace. That heart rate becomes your Zone 1 heart rate.
- Retest: at block transitions, as your training and fitness change.
Your coach reads the results with you and builds your zones from them. You know what each number means and why it is there.
Let heart rate do its real job
Heart rate is not the boss of your sessions, and it is not useless either. At ANC we read heart rate together with power, pace and how a session feels, never heart rate alone.
Heart rate shows us your durability through drift and decoupling on long sessions. It also helps us track your recovery.
Some days it leads. In heat and humidity, heart rate and feel lead and output targets give way. On steep hills, we use run power or feel, because Critical Speed does not hold there.
Check your zones today
- Do you know where your zones came from?
- Were they set from power and pace, or from a formula?
- When did you last test?
- Does your Zone 1 feel truly easy?
- Do you know when to trust heart rate and when to trust feel?
How ANC coaches
Every ANC athlete works with an experienced, educated coach. Every coach uses the same StressLogic system and philosophy, so your plan rests on one clear way of thinking.
Nothing is generic. Your zones come from your tests, your sessions fit your life, and your plan adapts as your fitness changes.
We coach your mind and body together, and we coach every level, from first race to podium. You learn why each session exists, so you can make good calls on your own.
Train on zones that are actually yours
If you have been training on a formula or an old race, your easy days may not be doing what you think. The fix is simple: test, anchor, and let your coach connect the dots.
Ready for zones built for you and a coach who explains every one? Start at angelanaethcoaching.com.
What's the Best Way to Set Your Heart Rate Zones?
Photo: Holly Koksel at the Anchor Down Ultra
References
- Ausland Ã…, Kelemen B, Seiler S. An exploratory study of maximal heart rate determination in endurance athletes: laboratory testing vs. field based. Front Sports Act Living. 2026;8:1806303. doi.org/10.3389/fspor.2026.1806303
- Esteve-Lanao J, Sellés-Pérez S, Arévalo-Chico H, Cejuela R. Towards accurate reference values for heart rate and speed zones by aerobic fitness and sex in long distance runners. Sports (Basel). 2026;14(1):29. doi.org/10.3390/sports14010029
Study notes: the first study used athletes' own reported field max heart rate and was exploratory. The second tested runners only, on a treadmill.