12- to 15-minute period, arriving at your maximum aerobic level only
after 15 minutes. At this point, you can maintain your maximum aer-
obic heart rate until nearing the end of your workout, when you begin
to cool down.
The Cool-Down
The final 12 to 15 minutes of your workout are also important; it’s
vital to slowly re-establish nearly normal circulation without “pool-
ing” blood in the muscles. You want to re-establish the normal circu-
lation in the organs and glands to begin the 24-hour process of recov-
ery and obtaining the benefits from your exercise. This slow lowering
of the heart rate from the maximum aerobic level back to near-resting
level is called the cool-down. Carefully bring the heart rate back
down by slowing down your activity. Attempt to reach your starting
heart rate, which is often not possible — but at least get within 10
beats of your starting heart rate.
The following graph shows heart-rate changes in relation to time
during a 45-minute workout — A: Warming up, B: Maintaining the
maximum aerobic level of 140 , and C: Cooling down.
Stretching and Flexibility
From your earliest years in school you were probably taught to
stretch before exercising. Even people who don’t work out sometimes
think stretching is a good way to get rid of body aches and pains and
208 • IN FITNESS AND IN HEALTH
160
140
120
100
80
60Warm Up, Cool Down
Like the warm-up, the cool-down is important.
It allows for recovery of muscles and organs.0 5 10 15 20 25 30 35 40 45