Heart rate zones
Five heart rate bands from easy to all-out, set automatically from your Apple Health data like Apple's Workout app, or from values you enter.
Zones split your workout heart rate into five bands, from easy in zone 1 to very hard in zone 5, and Pajdo shows the minutes you spent in each.
Automatic zones start from the date of birth in Apple Health, as in Apple's Workout app. Pajdo estimates your maximum heart rate as 208 minus 0.7 times your age, a formula from an analysis of 351 studies that suits older adults better than 220 minus age. The gap between your usual resting heart rate and that maximum is your heart rate reserve, which exercise guidelines use to set intensity. Zone 1 starts halfway up it, and zones 2 to 5 start 60, 70, 80 and 90% of the way up. Both values refresh on the first of each month.
Without a date of birth, Pajdo estimates your maximum from the highest heart rate you've held in a workout over the past year, which reads low if you rarely go all-out. Without a resting heart rate, zones are shares of your maximum.
Any formula is an estimate. If you know your maximum from a test or a coach, enter it in Settings, with a resting heart rate if you like, and Pajdo uses it right away.
Worth a try
Run slow enough to chat
The talk test is the simplest pace gauge there is. At a moderate effort you can still talk but couldn't sing a song. If you can only get out a few words between breaths, that's vigorous.
Easy running isn't lazy running. Reviews of how well-trained runners and cyclists train find most of their time is spent at low intensity, with a smaller slice of hard work.
Try it: run your next few outings at chatting pace and aim for time on your feet, not speed. Save the puffing for one or two sessions a week.
Keep reading
Sources
- View heart rate zones on Apple Watch, Apple Support
- Age-predicted maximal heart rate revisited (Tanaka, Monahan and Seals 2001), Journal of the American College of Cardiology
- ACSM position stand: quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness (Garber et al. 2011), Medicine & Science in Sports & Exercise
- Benefits of exercise, NHS
- Couch to 5K running plan, NHS Better Health
- The training intensity distribution among well-trained and elite endurance athletes (Stöggl and Sperlich 2015), Frontiers in Physiology
Checked against these sources on September 15, 2026.
This is general wellness information, not medical advice. If a number worries you, or stays away from your usual for a while, talk to a doctor.