CHAPTER INVESTIGATION
Heart Rate and Exercise
OVERVIEW AND PURPOSE In this activity, you will calculate your resting, maximum, and target heart rates. Then you will
examine the effect of exercise on heart rate. Before you begin,
read through the entire investigation.
Procedure
Make a data table like the one shown on the sample
notebook page.
MATERIALS
• notebook
• stopwatch
• calculator
• graph paper
Measure your resting heart rate.
Find the pulse in the artery of your
neck, just below and in front of the
bottom of your ear, with the first two
fingers of one hand. Do not use your
thumb to measure pulse since the
thumb has a pulse of its own. Once
you have found the pulse, count the
beats for 30 seconds and multiply the
result by 2. The number you get is your
resting heart rate in beats per minute.
Record this number in your notebook.
step 2
Calculate your maximum heart rate by subtracting your age from
220. Record this number in your notebook. Your target heart
rate should be 60 to 75 percent of your maximum heart rate.
Calculate and record this range in your notebook.
Someone who is very athletic or has been exercising regularly for
6 months or more can safely exercise up to 85 percent of his or
her maximum heart rate. Calculate and record this rate in your
notebook.
Observe how quickly you reach your
target heart rate during exercise.
Begin by running in place at an
intensity that makes you breathe
harder but does not make you
breathless. As with any exercise,
remember that if you experience
difficulty breathing, dizziness, or
chest discomfort, stop exercising
immediately.
638 Unit 5: Human Biology
step 5
Every 2 minutes, measure your heart rate for
10 seconds. Multiply this number by 6 to find
your heart rate in beats per minute and record it
in your notebook. Try to exercise for a total of
10 minutes. After you stop exercising, continue
recording your heart rate every 2 minutes until it
returns to the resting rate you measured in step 2.
Observe and Analyze
Write
Conclude
It Up
1. INFER Why do you think that heart rate
increases during exercise?
2. IDENTIFY What other body systems are
affected when the heart rate increases?
3. PREDICT Why do you think that target
Write
It Up
heart rate changes with age?
4. CLASSIFY Create a table comparing the
1. GRAPH DATA Make a line graph of your
intensity of different types of exercise, such
as walking, skating, bicycling, weight lifting,
and any others you might enjoy.
heart rate during and after the exercise.
Graph the values in beats per minute versus
time in minutes. Your graph should start at
your resting heart rate and continue until
your heart rate has returned to its resting
rate. Using a colored pencil, shade in the area
that represents your target heart-rate range.
INVESTIGATE Further
CHALLENGE Determine how other exercises
affect your heart rate. Repeat this investigation
by performing one or two of the other exercises
from your table. Present your data, with a graph,
to the class.
2. ANALYZE DATA How many minutes of
exercising were needed for you to reach your
target heart rate of 60 to 75 percent of maximum? Did your heart rate go over your target
range?
3. INTERPRET DATA How many minutes
after you stopped exercising did it take for
your heart rate to return to its resting rate?
Why do you think your heart rate did not
return to its resting rate immediately after
you stopped exercising?
Exercise
Heart Rate and
te:
Resting heart ra
t rate:
Maximum hear
maximum):
te (60–75% of
Target heart ra
imum):
te (85% of max
Target heart ra
d After Exercise
Rate During an
Table 1. Heart
Time (minutes)
0
2
4
6
8
10
12
14
16
18
20
Heart rate
e)
(beats per minut
Chapter 18: Transport and Protection 639