Suunto t3 User Manual page 23

After training, you can see how much of the session was spent in each zone. Each zone is a range
of heart rates expressed as a percentage of your maximum heart rate (which is calculated based
on the age you enter in the Personal settings menu). Accept the settings with a short press of the
ENTER button, which also moves you on to the next menu item.
The default heart rates for zones 1-3 are 60-70%, 70-80%, and 80-90% of your maximum heart
rate, but if you are following a specially designed training program, enter the zone values that have
been tailored towards your individual goals. The benefits of training in each default zone are shown
in the table below.
Heart rate Default setting
zone
Zone 1 60 - 70% of maximum heart
(Fitness rate
zone)
Zone 2 70 - 80% of maximum heart
(Aerobic rate
zone)
Zone 3 80 - 90% of maximum heart
(Threshold rate
Zone)
NOTE
Main benefit
Improves your basic endurance, and helps you to recover from harder
training sessions. Can also be used in weight control.
Improves your aerobic capacity. This is the preferred zone if you are
training for an endurance event.
Improves your maximum aerobic capacity and lactate tolerance ability
(anaerobic threshold) - meaning your maximum endurance will
improve and you'll be able to fight fatigue better.
The heart rate zone defaults follow the guidelines of the American College
of Sports Medicine for exercise prescription.
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