Heart rate zones split training effort into five bands, each driving a different adaptation. Anchor them to your lactate threshold heart rate (LTHR), not to a maximum heart rate formula, because age-based formulas carry a 10 to 20 bpm error. For trekkers, Zone 2 matters most: the aerobic base at 85 to 89 percent of LTHR, roughly 75 to 79 percent of maximum heart rate, the effort at which you can still talk in full sentences. A trek day is mostly a Zone 1 to 2 effort repeated for days, so that is where most of your training belongs.
Pick the tests you want and get one report with your biggest gap before day one. Free, a few minutes, no signup.
Why heart rate zones matter on a trek
Intensity decides which system gets the work. A trek adds one constraint a race does not: the effort repeats. Walk day one too hard and you pay for it on day five. That makes the lower zones disproportionately important, and it makes the discipline to keep easy days easy the single most useful habit in a trek plan.
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: elite endurance competitors spend roughly 80 percent of their training time at low intensity and 20 percent at high intensity (Seiler & Kjerland, 2006; Stöggl & Sperlich, 2014). For a trekker the case is even stronger, because the trek itself is almost all low intensity.
The five zones, trekker's edition
Each zone is a percentage of your lactate threshold heart rate (LTHR). This is Joe Friel's five-zone model, and the one we use, because LTHR is a landmark you can measure, while age-based maximum heart rate formulas carry an error of 10 to 20 bpm. That margin is wide enough to put your easy days in the wrong zone.
The percent-of-maximum figures are rough orientation only. They assume LTHR sits at about 88 percent of maximum heart rate, a reasonable average, but the real ratio varies from roughly 80 to 92 percent between people and rises as you get fitter.
Zone 2 for trekking: why it carries the week
If you take one thing from this guide: most of your training time belongs in Zone 2. A trek is won by endurance, not power: hours of steady walking with a pack, repeated the next day. Training the system you will use is the most direct preparation there is.
The polarised-training research backs this up. In elite cross-country skiers, runners and rowers, the consistent pattern was about 80 percent of training below the first ventilatory threshold (roughly Z1 to Z2) and 20 percent above the second (Z4 to Z5), with little time in between; those who trained more in the middle did worse (Stöggl & Sperlich, 2014).
Most people train at one intensity: medium-hard. Go easier on easy days, harder on the one hard day, and stop living in the middle.
For a trekker that means long Zone 2 walks are not junk volume; they are the work. The one weekly interval session matters too, but as a top-up.
Heart rate on the trek itself
Zones are a training tool. On the trail, three things move the number:
- Altitude. Heart rate drifts up by 5 to 15 bpm at altitude, in heat, and after several hard days. The pace that read Zone 2 at home reads Zone 3 at 4,000 m. On Everest Base Camp you sleep five nights at or above 4,000 m; expect the number to sit higher all week.
- Consecutive days. Fatigue accumulates across stages. If the same pace reads higher on day five than on day two, that is the trek talking, not a reason to push.
- Descents. Going down feels easy on the lungs and reads low on the watch, but it is the hardest load your legs take all day. Heart rate understates the cost; see eccentric training for trekkers.
On the trek, trust the talk test more than the number: if you can speak in full sentences, the pace is right, whatever the watch says. Training at home is where heart rate zones earn their keep.
Maximum heart rate: why it matters less than you think
Most people meet heart rate zones through a maximum heart rate formula, usually 220 minus age. The formula misses real maximum heart rate by a wide margin for many people, and zones built on a wrong ceiling are wrong all the way down. For trekking, the more useful anchor is lactate threshold heart rate, roughly the effort you can hold for about an hour, because the whole activity happens below it. Maximum heart rate still tells you how much headroom you have on the interval day. It should not be what your easy days are built on.
How to find your zones
Get your LTHR right and every zone falls into place. Three practical ways, from very accurate to good enough to start tomorrow:
- Field test (the one to do). A 30-minute effort at the hardest pace you can sustain, on a steady hill or a treadmill at a fixed incline. Your average heart rate over the final 20 minutes is your LTHR (Friel method). Free, accurate, and it hurts.
- Lab test. A graded exercise test in a sports-science lab measures your thresholds directly. The most accurate, if you have access to one.
- Age-based estimate (starting point only). Estimate maximum heart rate with the Tanaka formula, then take 88 percent of it as a stand-in LTHR. A placeholder, not a prescription; use it to start, then test.
The calculator runs the estimate for you. If you know your LTHR from a field test or your watch, enter it and the zones become properly yours:
Common mistakes trekkers make with heart rate
- Going too hard on long walks. A four-hour walk in Zone 3 is not Zone 2 endurance training; it is grey-zone tempo that leaves you tired for days. Slow down. If you cannot speak in full sentences, you are going too hard.
- Making the hard day too easy. The weekly interval session should be genuinely hard. That is what lifts the threshold, which makes every Zone 2 hour feel easier.
- Treating the descent as rest. Low heart rate, high leg load. Pace the descent like the rest of the day.
- Confusing average with steady. A walk with bursts to Zone 4 on every steep section can average out to Zone 2 on your watch, but it is not the same adaptation. Steady is the point.
A weekly distribution that works
The polarised principle, trek-shaped: most of the week at Zone 1 to 2, one hard session, and the weekend pair of long days back to back. A representative build-phase week from our 16-week trek plans:
- Mon · easy 60 minutes, Zone 2
- Tue · intervals: 4 x 4 minutes in Zone 4 with 3 minutes easy between, or hill repeats
- Wed · rest or mobility
- Thu · midweek vertical: stairs, incline or hills, Zone 2, pack on
- Fri · eccentric strength
- Sat · long walk, Zone 2, full trek pack
- Sun · second walk on tired legs, Zone 1 to 2
Roughly 80 percent of the week sits at Zone 1 to 2, with one session at threshold. The plans for Kilimanjaro, Everest Base Camp, Inca Trail, Tour du Mont Blanc, Annapurna Circuit, Walker's Haute Route, Alta Via 1, Tour of Monte Rosa, GR20, Laugavegur Trail, Toubkal Circuit, Huayhuash Circuit, Santa Cruz Trek, Salkantay Trek, Condor Trek, Quilotoa Loop, Inca Trail to Ingapirca, Torres del Paine W Trek, Torres del Paine O Circuit and Michinoku Coastal Trail use exactly this structure, sized to each trek's days.
Common questions
What heart rate is zone 2?
On the Friel five-zone model, Zone 2 is 85 to 89 percent of your lactate threshold heart rate (LTHR), roughly 75 to 79 percent of maximum heart rate. In feel, it is the hardest effort at which you can still talk in full sentences. It is the aerobic base zone and the most important intensity for trekking, because a trek day is mostly a Zone 1 to 2 effort repeated for days.
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 break up and you need a breath partway through. If an easy walk no longer feels easy, you have probably slipped into Zone 3.
What heart rate zone should I walk in on a trek?
Mostly Zone 1 to 2: a pace at which you can talk in full sentences all day. On the trek itself, altitude, heat and consecutive days push heart rate up by 5 to 15 bpm at the same effort, so trust the talk test more than the number.
Do heart rate zones change at altitude?
The zone percentages do not change, but your heart rate at a given pace rises by 5 to 15 bpm at altitude, in heat and after several hard days. The same pace reads higher, so slow down to keep the effort conversational rather than chasing the number.
What is the lactate threshold?
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 builds quickly. Your lactate threshold heart rate (LTHR) is the anchor for every zone. A 30-minute field test, averaging your heart rate over the final 20 minutes, pins it far more precisely than an age-based formula.
Does max heart rate matter for trekking?
Less than most people assume. Trekking happens far below maximum effort, so zones anchored to lactate threshold heart rate describe it better than zones built on a maximum heart rate formula, which carries a 10 to 20 bpm error. Use maximum heart rate to cap the interval day; build Zone 2 from LTHR.
Do heart rate zones change with age?
The percentages do not: Zone 2 is always 85 to 89 percent of LTHR. The anchor moves: LTHR shifts with training, and maximum heart rate declines with age. Re-test every few months rather than setting zones once.
Keep reading
Take this further
- All trek guides · Twenty 16-week training plans built from each trek's stage profile, and the physiology behind them.
- Eccentric Training for Trekkers · Why trek descents hurt more than the ascents, and the short sessions that fix it.
- Altitude Acclimatisation for Trekkers · Sleeping altitude, go high, sleep low, and what your itinerary does that training cannot.
- The Science Behind TTM · Banister's fitness-fatigue model, polarised training and periodisation, applied to consecutive days.
The takeaway in one paragraph
Heart rate zones make sure your training matches the system you are trying to build. For a trek, that means a lot of Zone 2 (the engine), one weekly session at threshold (the top end), back-to-back long days on the weekend, and easy days that stay easy. The trekkers who get this right arrive with an engine that makes day five feel like day two.
