Department of Mathematics Education
Comparing your resting heart rate, exercise heart rate, and recovery heart rate is an ideal situation to represent positive and negative numbers. Students will find their resting heart rate, exercise heart rate, and recovery heart rate to find the class average rates. The data is generated in class.
To prepare for this activity, ask the class about averaging. Discuss how they average their grades. Be sure students know how to read a stopwatch, including reading hundredths of seconds and beyond. Do not forget to remind students that one-minute equals 60 seconds.
The materials you will need for this activity include timers and calculators. You can have students can work in groups of three. The roles for the three students are: timer, recorder, and jogger. The roles will then switch until everyone has been the jogger. Locate your pulse. The two pulses you can find most easily are the radial pulse and the carotid pulse. The radial pulse is located on your wrist near the base of your thumb. The carotid pulse is on the side of your throat beside your jaw. Find your pulse and count the number of beats in a 10 second period. Multiply this number by 6 to get the number of beats per minute. Write the number of beats per minute on a sheet of data paper as your resting pulse rate. Run in place for one minute. Immediately count your pulse beats for a 10 second period. Multiply this number by 6 to get the beats per minute. Record the number of beats as your exercising pulse rate. Rest for five minutes. Then count beats for a 10 second period. Multiply this number by 6 to get the beats per minute. Record this number as your recovery pulse rate. On the chalkboard, write the headings for resting pulse rate, exercising pulse rate, and recovery pulse rate. Record all the data for each class member on the chalkboard. Copy all the data to your record. Calculate the average pulse rate of the class for each state of activity. Use integers to report the difference between your pulse rate and the class average for each kind of rate. Use integers to report the increase form resting pulse rate to exercising pulse rate and the decrease from exercising pulse rate to recovery pulse rate. Report these changes for your own pulse rates and for the average pulse rates for the class.
When the lab is completed, discuss the meanings of the negative and positive integers in the lab results. As enrichment, have students determine their personal target heart rate during exercise. Students can use the following formula to approximate the recommended average target heart rate of 70% of their maximum heart rate: 220 – your age. Students can also use this formula to determine the target heart rate of family members, friends and classmates. Then have students calculate the difference between the resting heart rate and the target heart rate.