Your heart rate tells you how hard your body is working.
Heart Rate Zones turn that signal into something you can train with and measure your effort.
What they are
A heart rate zone is a range of beats per minute, expressed as a percentage of your maximum heart rate (the fastest your heart can safely beat).
As you move harder, you climb from one zone to the next.
A common starting estimate for max heart rate is 220 minus your age. Your true max is personal, and most devices refine it over time.
Why they matter
Steps and eHR minutes tell you that you moved. Zones tell you how hard.
Intensity is what drives the health benefits.
Different zones, different gains
Lower zones build endurance and aid recovery; higher zones build speed and peak fitness. The mix is what matters.
The sweet spot for health
Major health guidelines target moderate-to-vigorous activity — roughly Zone 2 and up. That is where the heart-health benefit lives.
Train smarter, not just harder
Zones keep easy days easy and hard days hard — so you make progress without burning out or overtraining.
How this shows up in Paceline
Paceline counts the minutes you spend with an elevated heart rate. Hit about 150 in a week and earn your Streak. Zones are simply the map that shows where those minutes come from.
How to target them
Your device shows your live zone, but your body is a reliable guide too. The simplest tool is the talk test — how easily you can speak tells you where you are:
A simple way in: warm up through Zones 1–2, spend most of your time in Zone 2–3, and add short pushes into Zone 4–5 to build fitness — then ease back down to recover.
Why your zone minutes differ across devices
If your device and Paceline all show slightly different numbers for the same workout, that’s expected. Zones are calculated, not handed down, and every device makes its own assumptions:
How they read your heart
Wrist sensors estimate from light on your skin; chest straps read the electrical signal directly.
What they assume is your max
A different max shifts every zone boundary.
How they define a “zone minute”
Apple, Garmin, Fitbit and Whoop each use their own formula.
How often they sample
Brief spikes near a boundary can land on either side.
Heart rate ranges are general guidelines based on a percentage of estimated maximum heart rate, for educational purposes only — not medical advice. Talk to a healthcare provider before starting or changing an exercise program.
