Heart rate zones

Your heart rate shows how hard you are really working. It is split into zones, as a share of your maximum heart rate:

• Zone 1 (50 to 60 %): very easy, recovery.
• Zone 2 (60 to 70 %): aerobic base, the pace of easy runs.
• Zone 3 (70 to 80 %): moderate.
• Zone 4 (80 to 90 %): threshold, tempo.
• Zone 5 (90 to 100 %): short intervals, sprints.

Maximum heart rate is roughly 220 minus your age: that is what Kadence uses, with your Apple Watch measuring your heart during the session.