Measuring Heart and Breathing Rates
Do not have students use the carotid artery in the neck to find their pulse. Applying too much pressure there could stimulate a reflex mechanism that can slow down the heart.
The safest and most common site to check pulse is on the thumb side of the wrist (radial pulse). Use the middle finger and ring finger together to apply slight pressure at the location shown. This is the pulse site recommended for the general public by the National Heart, Lung, and Blood Institute, National Institutes of Health.
Part 2. Gathering Data
1. Explain to students that they will be investigating their breathing and heart rates. Make sure they understand that a “rate” is a measure of “how fast” or “how slow” something is happening.
2. Group the students into pairs. Ask them to sit quietly and breathe normally. Have one student count the number of times his/her partner inhales (breathes in) in one minute, and record the results on the “Heart and Lungs Data Sheet.” Older students can time themselves, using a wristwatch or stopwatch. If a student has difficulty observing the breathing of his/her partner, instruct the student being observed to dangle a strip of tissue in front of his/her nose. Have students repeat the measurements at least three times to calculate an average. Then instruct the students to switch jobs.
3. With younger students, conduct this procedure as a whole class activity. You can either time them or direct the timing, while students take turns counting and recording their partners’ breathing rates.
4. Prepare the students to measure their pulse rates (heart beats per minute) by demonstrating the safest way to locate a pulse point (see “Safety Issue,” above and the following slide). Give students time to locate their pulse points and practice counting beats.
5. Have students measure their heartbeats by counting the number of times they feel a tiny surge at their pulse points, while their partners time them for 15 seconds. Older students should enter this value on their worksheets and multiply by four to obtain the number of beats per minute. They should take three readings. Younger students may add this value four times to find beats per minute. Have the students switch jobs and repeat the process. Again, with younger students, you probably will want to direct the activity and measure the time.
6. Next, tell the students that they are going to investigate their breathing and pulse (or heart) rates after physical activity. Ask, What do you think will happen to your heart rate when you exercise? What about your breathing rate? Have one member of each team run in place for one minute and sit down. Have their partners determine their breathing rates again. Older students should repeat this procedure three times. Then, let the students switch jobs and repeat the process. This step should be teacher-directed for younger students.
7. To investigate pulse rate after activity, have the students repeat the process described in steps 3 and 4 after running in place for one minute.
Part 3. Graphing
1. Draw two large grids for class graphs on chart paper or on the board. Label one grid “Heartbeats Per Minute” and the other “Breaths Per Minute.” Lines on the vertical axis should be 6 cm apart. Lines on the horizontal axis should be approximately 12 cm apart. Make sure students understand that they were able to quantify their heart rates by counting the tiny surges of blood moving through an artery.
2. Using blue for resting rate and red for active rate, have students write their names and rates on the appropriate cut-outs. Tape students’ cut-outs on the appropriate class graphs OR help each student position his or her cut-outs on the graphs.
3. Ask, Where are most of the blue hearts on the graph? How about the red hearts? Where are the blue lungs? The red lungs? How does exercise affect a person’s breathing rate? Heart rate? Help students notice that heart and breathing rates change together.
Keywords: active rate | air | breath | breathing rate | diaphragm | exercise | exhale | heart | heart rate | heartbeat | inhale | lungs | oxygen | pulse | respiration | resting rate | slides | lesson
- Moreno, N., Tharp, B., and Dresden, J. (2011) The Science of Air Teacher’s Guide. Baylor College of Medicine: Houston. ISBN: 978-1-888997-74-3
- Illustrations by M.S. Young © Baylor College of Medicine.
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Funded by the following grant(s)
My Health My World: National Dissemination
Grant Number: 5R25ES009259
The Environment as a Context for Opportunities in Schools
Grant Number: 5R25ES010698, R25ES06932
Foundations for the Future: Capitalizing on Technology to Promote Equity, Access and Quality in Elementary Science Education