2) H
EART RATE INTERVAL
This program also combines the standard HILL workout profile with the concept of Heart Rate
Zone Training. The default target heart rate* is calculated as 80 percent of the theoretical maxi-
mum
†
(HRmax), but the user can adjust the target rate during the workout setup. The workout
alternates between a hill, which brings the heart rate up to the target rate of 80 percent of HRmax,
and a valley, which brings the heart rate down to 65 percent of HRmax. After a standard three-minute
warm-up, the workout progresses toward the first hill and heart rate goal. Once the goal is reached,
the hill continues for three minutes. Then, the level decreases into a valley. Once the 65 percent of
HRmax goal is reached, the valley continues for three minutes, after which the next hill begins. The
user's fitness level determines the number of hills and valleys encountered within the duration. At the
end of the duration, the workout goes into a cool-down phase. If the heart rate goes above the the-
oretical maximum
†
for more then 45 seconds, the treadmill automatically goes into pause mode.
If the user does not reach a heart rate goal after five minutes, the Message Area displays a prompt to
increase or decrease speed, depending on whether the workout is in a hill or valley phase. The pro-
gram does not proceed to a new heart rate goal until the user reaches the current goal.
42
† Defined by the American College of Sports Medicine's "Guidelines for Exercise Testing and Prescription" as equal to
220 minus an individual’s age.
* Target Heart Rate (THR) is a percentage of the theoretical maximum (HRmax). A 40-year-old user's recommended THR
for the HEART RATE INTERVAL workout is 144 or 80 percent of the maximum; so the equation would be (220-40)*.80 =
144.
