Lesson 2: Effects of Exercise on Heart Rate and Breathing Rate - OMSI

OMSI: OBPPage 3 <strong>of</strong> 4Ask students how fast they think their heart beats when they are sitting still. To demonstrate howhard the heart works every minute, have student volunteers try the following activity:! Set two wash basins next to each other on a table. (Be sure to protect the surface fromspills.) Fill one wash basin two-thirds <strong>of</strong> the way with water.! Have one student use a stopwatch or clock with a second hand to time one minute.! Give the other student a plastic cup that holds about 150 mL (about the amount <strong>of</strong> bloodan adult heart pumps with each beat).! Challenge the student to use the cup to try to move the water from one basin to the otheras fast as the heart pumps. To pump as fast as an average adult heart, the student wouldhave to move 70 cupfuls in one minute.ProcedurePart A1 Demonstrate for students how to take a pulse at the wrist (radial artery) andat the neck (carotid artery). To find a pulse rate: Place the index and middlefingers on your wrist or your neck. (Don't use your thumb. It has it's ownstrong pulse.) Hold your fingers there until you feel the steady beat <strong>of</strong> yourpulse. (You may have to move your fingers around a little until you find thestrongest pulse. Don't press too hard.)2 Help students find their own pulses at these two places. Ask students whatthe pulse rate measures. Explain that with each heartbeat, the heart sends awave <strong>of</strong> blood surging through the blood vessels known as arteries. You canfeel this surge <strong>of</strong> blood most easily at places where arteries are near thesurface <strong>of</strong> the skin, such as at the inside <strong>of</strong> the wrist or the side <strong>of</strong> the neck.By measuring pulse rate we are actually measuring heart rate.3 Have all students measure their pulse rate while seated quietly at theirdesks. Explain that this is a resting pulse rate. Students can determine theirpulse rate by counting the pulses in 15 seconds and multiplying that numberby 4 (to get heartbeats per minute). Have students find their pulses, then givea signal and have students count the pulses, while you time 15 seconds.4 Ask students: What do you think happens to your heart rate when you run?Why? Record students' hypotheses on the board.5 Then have students jog in place for 1 minute. At the end <strong>of</strong> that time, havethem determine their heart rates as they did before.6 Have students compare their resting and active heart rates. Collect classdata in a chart on the board. Plot the data on a bar graph. Have studentslook for patterns in the data.7 Let students work in small groups to investigate the effect <strong>of</strong> an activity onheart rate. Students might choose an activity such as stair climbing, laphttp://www.omsi.edu/explore/life/obp/u2_l2_body.html5/15/2001