Garmin Cycling Coach without a power meter: what you keep and how to train on heart rate

What goes dark without power, feature by feature

On a bike, cycling VO2 max, Acute Load, FTP detection and Daily Suggested Workouts all need power, and Training Status is built partly from the first two. Garmin groups them in one line: cycling performance measurements require a heart rate monitor and a power meter [Garmin Edge 840 Performance Measurements]. A strap alone feeds none of them.

Garmin does not say Cycling Coach requires a power meter. It says cyclists of any kind can start a training plan in the free Garmin Connect app, and that to get the full benefit you need three products: a compatible Edge, a heart rate monitor or compatible watch, and a power meter [Garmin Cycling Coach]. The plan adapts from six inputs: training status, training load, load focus, VO2 max, recovery time and recently completed workouts. Without power on the bike, at least four of those six have no cycling value to read. Garmin does not publish how the plan behaves with those inputs missing.

Daily Suggested Workouts sets a firmer gate. The Edge 840 manual says you must ride with heart rate and power for one week to get workout recommendations, and that the suggestions are based on your previous activities saved to Garmin Connect [Garmin Edge 840 Suggested Workouts]. A rider with a strap and no meter never completes that week, so the suggestions never start.

The measurements follow the same rule. Cycling VO2 max, Acute Load and FTP auto-detect all sit under Garmin's performance measurements, and each needs a paired heart rate monitor and power meter on the bike [Garmin Edge 840 Performance Measurements]. Without them, the Edge's FTP comes only from your user profile. Garmin bases Training Status on changes to VO2 max, acute load and HRV status, so a heart-rate-only rider gives it no cycling VO2 max trend to compare. Our guide to Garmin's Unproductive status covers what that does to the status in detail. How the Edge's FTP test and auto-detect differ is its own spoke on Garmin FTP auto-detect accuracy.

Heart rate zones on a Garmin, and the one number they hang on

Garmin's default heart rate zones are percentages of maximum heart rate: 50 to 60%, 60 to 70%, 70 to 80%, 80 to 90% and 90 to 100% [Garmin Edge 840 Heart Rate Zones]. Those are the same five bands AdaptCycling uses. Every zone scales from your maximum heart rate, so that one number decides whether the plan is right.

The mapping is simple. Zone 2, at 60 to 70% of maximum, is the endurance work that should fill most of a week. Zone 4, at 80 to 90%, is threshold work, and zone 5 is VO2 max work. For a rider with a maximum of 185 bpm, zone 2 runs from 111 to 130 bpm and zone 4 from 148 to 167 bpm. Set the maximum 10 beats too high and every zone shifts up with it, so easy rides drift into tempo without the rider noticing.

Use a measured maximum, not an age formula. The highest heart rate you have actually seen at the end of an all-out climb or a hard sprint finish in the last few months is a better anchor than any equation, because formulas describe a population, not you. If you cannot find one, a hard effort with a fresh strap will produce it. If you want a watt-like threshold number as well, our guide on how to estimate FTP without a power meter covers the heart-rate and perceived-effort methods and where each one breaks down.

Then read long rides with drift in mind. Cardiovascular drift is a progressive decline in stroke volume after 10 to 20 minutes of exercise, which Coyle and González-Alonso attribute mainly to a rising heart rate [Coyle & González-Alonso 2001]. At a fixed heart rate, that means power falls as the ride goes on. A three-hour ride held under 130 bpm ends noticeably slower than it started, and that is physiology, not lost fitness. Hold the zone 2 ceiling for the first hour, then let it rise a few beats while breathing and cadence stay easy.

Where heart rate fails: short intervals, and what to use instead

Heart rate answers an effort after it starts, so it separates hard sessions poorly. In 63 well-trained cyclists, interval sessions at 95%, 106% and 117% of 40-minute time-trial power produced peak heart rates of only 89%, 91% and 94% of peak [Seiler & Sylta 2017]. Twenty-two points of power became five points of heart rate.

Put those numbers on Garmin's zones and the problem is plain. The 4 x 16-minute session peaked in zone 4, while the 4 x 8 and 4 x 4, ridden 11 and 22 points harder, both peaked in zone 5 [Seiler & Sylta 2017, Garmin Edge 840 Heart Rate Zones]. Blood lactate told the real story, rising from 4.7 to 12.7 mmol/L. A heart rate target on a 4-minute VO2 max rep is reached late in the rep, if at all, and a 30-second sprint is over before heart rate catches up.

Perceived effort fills the gap. In 2,560 people doing incremental tests on treadmills and cycle ergometers, Borg's 6 to 20 rating correlated with heart rate at r = 0.74 and with blood lactate at r = 0.83. The lactate threshold sat near an RPE of 11 and the individual anaerobic threshold near 14 [Scherr et al. 2013]. That makes RPE a valid intensity tool in its own right, not a fallback.

The working rule for a heart-rate-only rider is to split the jobs. Use heart rate for steady rides and long threshold reps of 10 minutes or more, where it has time to settle. Use RPE and completion for anything shorter: the question for a set of 4-minute reps is whether you held a hard, even effort through every one, not what number the strap reached. Heart rate still earns its place between reps, where a slow recovery is an early sign of fatigue.

A plan built on heart rate, delivered to Garmin Connect

AdaptCycling plans on heart rate when there is no power meter. Pick heart rate at setup, and the next 7 days of workouts go to your Garmin Connect calendar with heart rate ranges in beats per minute, built from your maximum heart rate. Your Edge or watch picks them up at its next sync.

Setup asks one question first: how do you want to train, power or heart rate. Pick heart rate and enter your maximum, or leave it blank and we estimate it from your age. Every step then goes out as an absolute bpm range in the same five bands as Garmin's zones [Garmin Edge 840 Heart Rate Zones]. All-out efforts go out with no target at all, because, as the interval data above shows, heart rate cannot steer them.

When you miss or move a ride, the week re-solves and the changed days are replaced on the Garmin Connect calendar within the hour. Load comes from each ride's own heart rate, and we do not read Garmin's Training Status, Training Readiness, HRV, sleep or other health data. Connecting Garmin gives us the rides you record from then on, not your past history; that comes in through intervals.icu or a Garmin Connect export upload. A heart-rate plan carries wider error bars than a power plan, and the short-rep limits above still apply.

This is one piece of the wider picture of training with a Garmin as a self-coached cyclist, which our pillar guide maps feature by feature. On price: Garmin Cycling Coach is free. AdaptCycling's week re-solve runs on its free tier, and the Coach tier, which adds the chat coach, costs $15 a month after a 14-day trial.

Quick answers

Sources cited in this guide

1. 01
   Garmin Cycling Coach. Garmin Coach training plans for cyclists. Garmin Blog.
2. 02
   Garmin Edge 840 Performance Measurements. Edge 840 Owner's Manual: Performance Measurements. Garmin.
3. 03
   Garmin Edge 840 Suggested Workouts. Edge 840 Owner's Manual: Daily Suggested Workouts. Garmin.
4. 04
   Garmin Edge 840 Heart Rate Zones. Edge 840 Owner's Manual: Heart Rate Zone Calculations. Garmin.
5. 05
   Seiler & Sylta 2017. How Does Interval-Training Prescription Affect Physiological and Perceptual Responses?. International Journal of Sports Physiology and Performance.
6. 06
   Scherr et al. 2013. Associations between Borg's rating of perceived exertion and physiological measures of exercise intensity. European Journal of Applied Physiology.
7. 07
   Coyle & González-Alonso 2001. Cardiovascular drift during prolonged exercise: new perspectives. Exercise and Sport Sciences Reviews.

More inside Training with a Garmin

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2. 02

   Garmin FTP auto-detect vs the guided test: which to trust

   What Garmin's FTP estimate, guided test and auto-detect each measure, when each drifts, and how to turn auto-detect off.

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3. 03

   Getting old Garmin rides into a training app

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4. 04

   Garmin Unproductive status for cyclists: what to ride next

   Why Garmin says Unproductive while you get fitter on the bike, and four rules for what to ride next.

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5. 05

   Garmin Edge training plans: every option compared

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6. 06

   Garmin workout not showing on your Edge or watch? The causes

   Why a planned workout misses your Garmin Edge or watch: device sync, the service's window, unsent workout types and the import permission.

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