Forerunner 50 Owner’s Manual
t
raIn
m
ode
Zone % of
Maximum
Heart Rate
Perceived Exertion
Benefits
1
50–60%
Relaxed, easy pace;
rhythmic breathing
Beginning-level aerobic
training; reduces stress
2
60–70%
Comfortable pace;
slightly deeper breathing,
conversation possible
Basic cardiovascular
training; good recovery
pace
3
70–80%
Moderate pace;
more difficult to hold
conversation
Improved aerobic
capacity; optimal
cardiovascular training
4
80–90%
Fast pace and a bit
uncomfortable;
breathing forceful
Improved anaerobic
capacity and threshold;
improved speed
5
90–100%
Sprinting pace,
unsustainable for long
period of time; labored
breathing
Anaerobic and
muscular endurance;
increased power
