Heart rate zones split training effort into five intensity bands, each driving a different adaptation. For mountaineers, zone 2 - the aerobic base at roughly 60 to 70 percent of maximum heart rate - matters most, because a long summit day is largely a zone 2 effort. Training the right amount in each zone is how you make sure your effort matches the system you are trying to build.
Why heart rate zones matter more for mountaineers
A road cyclist trains in five zones because intensity decides what physiological system gets the work. A mountaineer trains in five zones for the same reason, but with one extra constraint: a summit day can be eight to twelve hours long, mostly at low intensity, with hard surges where it counts. That makes the lower zones disproportionately important. Get them wrong and you crack on hour seven.
The five-zone model traces back to coaching frameworks built on Banister's training-load model (Banister et al., 1975) and refined by endurance researchers like Stephen Seiler. The headline finding from the modern research: elite endurance athletes spend roughly 80 percent of their training time at low intensity and 20 percent at high intensity (Seiler & Kjerland, 2006; Stöggl & Sperlich, 2014). For mountaineers, that distribution is even more extreme, because the objective itself is mostly low-intensity by volume.
The five zones, mountaineer's edition
Each zone is defined as a percentage of your maximum heart rate (HRmax) and serves a specific physiological purpose. The exact percentages vary across coaching systems, but the practical ranges are stable enough to use:
Why zone 2 dominates mountaineering training
If you take one thing from this guide: most of your training time should be in zone 2. The reasoning is straightforward. Mountaineering objectives are won by endurance, not by power. A six-hour summit day at altitude pushes a fit athlete to roughly zone 2 - that is the actual race. Training the same system you will use is the most direct preparation possible.
The polarised-training research backs this up. When Seiler and colleagues tracked elite cross-country skiers, runners, and rowers, the consistent pattern was 80 percent of training volume below the first ventilatory threshold (roughly Z1-Z2) and 20 percent above the second (Z4-Z5), with very little time in the middle (Stöggl & Sperlich, 2014). Athletes who trained more "in the middle" - that classic Z3 tempo zone - performed worse than athletes who polarised their distribution.
Most amateurs accidentally train at one intensity: medium-hard. Polarised training says go easier on easy days and harder on hard days. Stop living in the middle.
For mountaineers, the implication is concrete: long zone 2 hikes are not "junk volume" - they are the work. The hard threshold session you sneak in once a week matters too, but only as a top-up. Because zone 2 carries so much of the load, it is worth understanding on its own terms - our zone 2 training for mountaineering guide goes deeper on how to find it, how much to do, and what the sessions look like.
How to find your zones
There are three practical ways to set your zones, ranging from "very accurate" to "good enough to start training tomorrow":
- Lab test (gold standard). A graded exercise test in a sports-science lab measures your ventilatory thresholds directly. Most accurate, costs €100-300, requires a lab.
- Field test. A 30-minute time trial at maximum sustainable effort. Average heart rate from the final 20 minutes approximates your lactate threshold (Friel method). Free, accurate, hurts.
- %HRmax estimate. Use an age-based formula to estimate HRmax, then calculate zones as percentages. Less accurate (ages-based formulas have ±10 bpm error), but useful for getting started.
For most mountaineers starting out, the %HRmax method is the right first move. Use this calculator:
Common mistakes mountaineers make with HR training
A few patterns that trip up athletes who are otherwise doing the work:
- Going too hard on long days. A four-hour hike at zone 3 is not zone 2 endurance training, it is junk-zone tempo. Slow down. If you cannot speak in full sentences, you are too hard.
- Ignoring fatigue and altitude effects. Heart rate drifts up by 5-15 bpm at altitude, in heat, and after several days of hard training. The same effort that read 140 bpm last week reads 150 bpm today. Trust the effort, not just the number.
- Skipping zones for the descent. Coming down feels easy on the lungs but loads the legs. Zone 1-2 cardio with high eccentric load is real training stress. Pace the descent like the rest of the day.
- Confusing average HR with steady HR. A "zone 2" hike with bursts to zone 4 on steep sections averages out to look like zone 2 in your wearable's auto-zoning, but is not the same physiological adaptation. Steady is the point.
A simple weekly distribution that works
Apply the polarised principle: most weeks, four to five sessions in zones 1-2, one threshold session in zone 4, one optional VO2max top-up in zone 5. A representative week for a mountaineer 12 weeks out from a summit:
- Mon · easy 60 min Z2
- Tue · threshold intervals, 4 × 8 min Z4
- Wed · rest or 30 min Z1 walk
- Thu · long Z2 hike, 2-3 hours with vertical gain
- Fri · easy 45 min Z2 with mobility
- Sat · long mountain day, 4-6 hours mixed Z2 with surges
- Sun · full rest
Roughly 85 percent of weekly volume is at Z1-Z2, with 15 percent at threshold or above. That is the polarised model in practice, calibrated for someone training for a real summit.
If you want this kind of distribution built around your specific peak and adapted from your actual training, that is what an personalised mountaineering training plan does. The zone structure is the same; what changes is the timing of each block based on your fitness data and how close your objective is.
Common questions
What heart rate is zone 2?
Zone 2 sits at roughly 60 to 70 percent of your maximum heart rate. In feel, it is the hardest effort at which you can still hold a conversation in full sentences. It is the aerobic base zone, and for mountaineers it is the single most important intensity to train, because a long summit day is largely a zone 2 effort.
What is the anaerobic heart rate zone?
The anaerobic zones are the hard end of the scale - zones 4 and 5, roughly 80 to 100 percent of maximum heart rate. They sit at and above the lactate threshold, where your body can no longer clear lactate as fast as it produces it, so efforts there are short and sharp. Mountaineers use this work sparingly, usually one key session a week, to lift the top end of aerobic capacity. The mountain itself is rarely an anaerobic event.
How do I tell if I am in zone 2 or zone 3?
Use the talk test. In zone 2 you can speak in full, comfortable sentences. In zone 3 your sentences start to fracture and you need a breath partway through. Zone 3 is the moderate tempo zone many athletes drift into without noticing - too hard to be easy, too easy to be a real top-end stimulus. If an easy day no longer feels easy, you have probably slipped into zone 3.
Do heart rate zones change with age?
The zone percentages do not change - zone 2 is always around 60 to 70 percent of maximum heart rate. What changes is your maximum heart rate itself, which gradually declines with age. So the actual beats-per-minute that define each zone drift down over the years even though the percentages hold. This is why zones should be recalculated periodically rather than set once and forgotten.
What is the lactate threshold?
The lactate threshold is the intensity above which lactate builds up in the blood faster than the body can clear it. Below it, an effort feels sustainable; above it, fatigue climbs quickly. It sits roughly around the boundary between the tempo and threshold zones and is a key reference point for setting training intensities. A field or lab test pins it more precisely than an age-based estimate.
The takeaway in one paragraph
Heart rate zones are how you make sure your training stress matches the physiological system you are trying to build. For mountaineering specifically, that means a lot of zone 2 (the engine), one weekly key session at threshold (the top end), and disciplined recovery in between. The athletes who get this right arrive at the trailhead with both range and resilience. The ones who do not, train medium-hard for months and wonder why they cracked at hour seven.