The Heart Is a Muscle

Transcription

1 Lesson 5 The Heart Is a Muscle Objectives Students will: calculate their target heart rate* identify the relationship between target heart rate and physical activity* *Learning Objective Estimated Class Time Part A Calculations and Counting Pulse: 20 minutes Total Time: 20 minutes Part B Monitoring and Graphing Heart Rate: 16 minutes Conclusion: 4 minutes Total Time: 20 minutes Materials Needed Teacher 411: Physical Activity, pgs (for teacher s use only) Stopwatch, or a watch or clock with a second hand Calculating Target Heart Rate worksheet, pg. 71 (one copy per student) Exercise and Heart Rate worksheet, pg. 72 (one copy per student) Heart Rate Graph worksheet, pg. 73 (one copy per student) Lesson Preparation Review this lesson, including the documents listed in the Materials Needed section and the Teacher 411: Physical Activity, found at the end of this lesson. Make copies of the worksheets in the Materials Needed section. 65

2 The Heart Is a Muscle Part A Calculations and Counting Pulse 1. Inform students that in this lesson they re going to learn about how physical activity affects their heart rate. Tell them they ll start by getting an idea of their heart s pumping action from opening and closing their hand in a similar motion. Tell students that when you say Go they should count how many times they can open and close their hand, squeezing tightly each time, for 30 seconds. Instruct them to open and close their hand completely each time. Give the signal and then time students for 30 seconds. Ask a few students how many times they pumped their hand. Have them multiply their answer by 2 to get the number of times they would have pumped their hand in 1 minute. Ask how many students pumped their hand between 60 and 100 times. Explain that a number between 60 and 100 is how many times their heart has pumped and will pump every minute of their life. 2. State or paraphrase the following: Between 60 and 100 beats per minute is the resting heart rate of most people, including people your age. But when you exercise, your heart rate increases. Your target heart rate is the range that should be maintained during physical activity for 20 minutes in order to achieve the maximum benefit for your heart. The heart is a muscle and, just like any muscle, the more your heart is exercised, the better it will work. Moderate-to-vigorous physical activity, called MVPA, will help you achieve your target heart rate. What are some examples of MVPA? (Possible answers: Brisk walking, jogging, running, bicycling, tennis, dancing, jumping rope, rollerblading) In this lesson you re going to calculate your target heart rate and find out how fit your heart muscle is. 3. Give each student a Calculating Target Heart Rate worksheet. Explain the target heart rate zone formula and demonstrate its application by going over the example. Then have students complete the problems. Go over the correct answers. ( bpm; bpm; 3. answers will vary) Tell students to keep this worksheet because they will use it in the next CATCH lesson. 4. Inform students that in the next class they ll see how quickly their heart rate returns to its normal, or resting, rate after doing a few minutes of exercise. Tell them that since the activity will require counting their pulse, you re going to teach them how to do that now. State or paraphrase the following instructions: To find your pulse, place the index and middle fingers of one hand on the inside wrist of the other hand. Don t use your thumb because it has its own pulse, which may interfere with feeling your wrist pulse. 66

3 The Heart Is a Muscle Slide your two fingers toward the thumb side of your wrist. Count the number of beats you feel in 15 seconds. Multiply that number by 4. The total you get is your heartbeats per minute, which is your pulse and your heart rate. 5. Tell students that now they ll be ready to monitor their heart rate in the next CATCH lesson. Part B Monitoring and Graphing Heart Rate 1. Inform students that they re going to monitor their heart rate to see how quickly it returns to its normal, or resting, rate after doing exercise. Tell them they ll also find out why this is important. 2. Give each student an Exercise and Heart Rate worksheet. Briefly go over the directions. Have them complete Question Lead students in finding their resting heart rate, using the instructions in Part A of this lesson. Time them for 15 seconds as they count their pulse. Then have them multiply the number of beats they counted by 4 and fill out the third and fourth columns of the chart in the worksheet. 4. Lead students in a physical activity for 2 minutes. You can facilitate this by using your own method (make sure you demonstrate moderate-to-vigorous physical activity), or you can use one of the suggestions provided below: OPTIONAL: You may want to do a practice run of the physical activity for 15 seconds to make sure that everyone can do the activity and can hear you when you ask them to stop. Perform the following activities inside or outside the classroom, alternating between the different exercises: running in place, jumping jacks, knee lifts, squats, jumping rope with an invisible rope, push-ups, and free style. Students could be taken to an outdoor area to run around for 2 minutes, as long as they are all active and can be quickly gathered to an area where they can easily hear you. 5. After the 2 minutes of physical activity is up, have students wait 15 seconds. Then instruct them to (1) count their pulse when you say Go and (2) record the number of beats they counted in the Immediately after exercising row under Beats counted in 15 sec. (Remind them not to perform the multiplication at this time.) 6. Students should continue this pattern of waiting for 15 seconds, counting their pulse, and recording the number of beats, until that number is the same as it was for their resting heart rate, or until the second column is filled whichever comes first. 7. Instruct students to (1) do the calculations needed to complete the third and fourth columns of the chart, (2) complete the Heart Rate Graph worksheet, and (3) answer Questions 1 3 below the graph. 67

4 The Heart Is a Muscle Conclusion 1. As time permits, ask a few students to share their answers to Questions State or paraphrase the following: During exercise, a healthy heart quickly soars to within its target range. The better shape a heart is in, the faster the heart rate will return to normal that is, its resting heart rate. Also, people who exercise regularly often have a very low resting heart rate. This is because their heart is stronger and pumps more blood each time it contracts. Finally, the heart is a muscle, and muscles need to be exercised to stay strong. Exercising keeps your heart strong and healthy so that it can continually pump blood through your body. To have a healthy heart, it s important to do 60 minutes of some kind of physical activity every day that puts your heart into its target range for at least 20 minutes. Extension Activity Coordinate with the PE teacher to assign students to take their heart rate while participating in PE class. Students should take their heart rate at the beginning, in the middle, and at the end of the class. Have students report their findings in the classroom and graph the results on a Heart Rate Graph handout. Sources Adapted from HEADS UP 2008 Nutrition/Physical Activity Second Edition module Target Heart Rate and The Heart is a Muscle activities Physical Activity for Everyone. Centers for Disease Control and Prevention web site: Physical Activity for Children: A Statement of Guidelines for Children Ages 5-12, 2nd Edition. National Association for Sport and Physical Education web site: Additional resources can be found in the appendix. 68

5 Lesson 5 The Heart Is a Muscle - Teacher 411 Teacher 411: Physical Activity Regular physical activity can both improve a person s health and reduce the risk of developing disease. It helps control weight; makes bones, muscles, and joints stronger; and helps prevent or reduce symptoms of stress, anxiety, and depression. Thirty minutes of physical activity most days of the week also reduces the risk of heart disease (the leading cause of death in the United States), as well as the risk for stroke, colon cancer, diabetes, and high blood pressure. Yet, despite all these benefits, more than 60% of adults do not get enough exercise, and more than 25% get none at all. A third of young teenagers do not get vigorous exercise on a regular basis, and their activity levels decline as they get older. To establish an effective exercise routine, there are four important concepts to keep in mind: Frequency, Intensity, Time, and Type (F.I.T.T.). Frequency: How often you exercise Intensity: Your level of physical exertion during exercise Time: The amount of time you spend exercising Type: The type of exercise you are performing (aerobic, strength training, etc.) The Centers for Disease Control and Prevention (CDC) offers the following recommendations for ADULTS: Cardio or aerobic activities (choose one of the following) Resistance, strength-building, and weight-bearing activities A minimum of 30 minutes of moderate-intensity physical activity per day (such as brisk walking) most days of the week. A minimum of 20 minutes of vigorous-intensity physical activity (such as jogging or running) 3 days a week. Two days a week, incorporate strength training into your routine. Strength training activities, such as weight lifting, maintain and increase muscle strength and endurance. A goal to work toward is completing 6 8 strength training exercises, with 8 12 repetitions per exercise. The National Association for Sport and Physical Education (NASPE) offers the following guidelines for CHILDREN/TEENS: Guideline 1 Guideline 2 Guideline 3 Guideline 4 Children should accumulate at least 60 minutes, and up to several hours, of age-appropriate physical activity on all or most days of the week. Children should participate in several bouts of physical activity lasting 15 minutes or more each day. Children should participate each day in a variety of age-appropriate physical activities designed to achieve optimal health, wellness, fitness, and performance benefits. Extended periods (periods of 2 hours or more) of inactivity are discouraged for children, especially during the daytime hours. 69

6 Lesson 5 The Heart Is a Muscle - Teacher 411 When you exercise, it is important to work out at an intensity level that is right for you. There are a number of different ways to figure out when you are exercising at the appropriate level of intensity. Calculating your target heart rate is one way. To exercise safely and receive the maximum cardiovascular benefit when you exercise, you should try to keep your pulse rate within the target heart rate zone. To determine this zone, you first need to determine your maximum heart rate, which is the maximum number of times your heart should beat in one minute. To calculate your maximum heart rate, subtract your age from 220. If you are just beginning to become physically active, you should gradually increase your activity to moderate-intensity exercise trying to go from couch potato to sport superstar in one step can lead to injuries. For moderate-intensity exercise, your target heart rate should be between 50% and 70% of your maximum heart rate. For example, a 13-year-old girl would have a maximum heart rate of = 207 beats per minute (bpm). Her 50% and 70% levels would be: 50% level: 207 X 0.50 = 104 bpm 70% level: 207 X 0.70 = 145 bpm So if this 13-year-old kept her heart rate between 104 and 145 bpm during the time she exercised, this would count as moderate-intensity exercise. Vigorous-intensity exercise is when the pulse rate is between 70% and 85% of the maximum target heart rate. To meet the physical activity recommendations, a person should perform this type of exercise at least three times a week for 20 minutes. Here are some examples: Moderate-Intensity Activity Vigorous-Intensity Activity (3.5 to 7 Kcal/min) (more than 7 Kcal/min) Walking Bicycling on level ground Weight training with free weights Jogging or running Basketball game (fast) Wheeling your own wheelchair Dancing Shooting baskets Swimming Skateboarding Bicycling on hills Karate, judo, taekwondo Soccer Jumping rope 70

7 Lesson 5 The Heart Is a Muscle - Worksheet 1 Name: Date: Pd: Calculating Target Heart Rate Target Heart Rate: The heart rate range that should be maintained during aerobic exercise for 20 minutes for optimal cardiovascular fitness. This range is also called the Target Heart Rate Zone. Target Heart Rate Zone Formula Lower Limit = (220 age) x 50% Upper Limit = (220 age) x 70% EXAMPLE: What is the Target Heart Rate Zone for a 13-year-old girl? Express your answer in beats per minutes (bpm). Lower Limit = (220 13) x 50% = 104 bpm Upper Limit = (220 13) x 70% = 145 bpm Target Heart Rate Zone = 104 to 145 bpm PROBLEMS: Directions: Calculate the Target Heart Rate Zone for the following people. Show your work. (If you get a decimal in your answer, round up if 0.5 or higher.) 1. A 37-year-old woman who swims for 1 hour at a time, 6 times a week. 2. A 52-year-old man who jogs 3 miles a day. 3. You. (Your age: ) 71

8 Lesson 5 The Heart Is a Muscle - Worksheet 2 Name: Date: Pd: Exercise and Heart Rate 1. Write your target heart rate zone from the Calculating Target Heart Rate worksheet. 2. Your teacher will lead you in finding your resting heart rate by counting your pulse. Calculate and record your resting heart rate in the Resting (yours) row of the chart. 3. Your teacher will lead you in 2 minutes of physical activity. 4. As soon as you finish the physical activity, when your teacher says Go, count your pulse for 15 seconds. Record the number of beats you counted in the Immediately after exercising row under Beats counted in 15 sec. (Don t multiply to find the total at this time.) 5. Wait for 15 seconds. Then count your pulse again and record the number of beats you counted in the seconds after exercising row under Beats counted in 15 sec. Continue this pattern of waiting for 15 seconds, counting your pulse, and recording the number of beats in the appropriate row of the chart. Do this until the number of beats you count in 15 seconds is the same as it was for your resting heart rate, or until the second column is filled whichever comes first. Heart rate Beats counted in 15 sec. Multiplied by 4 Total Resting (example) x 4 68 Resting (yours) Immediately after exercising seconds after exercising seconds after exercising seconds after exercising seconds after exercising seconds after exercising Complete the chart by doing the required calculations and filling in the third and fourth columns. Use the Heart Rate Graph worksheet to graph the values in the fourth column. Then answer Questions 1 3 below the graph. 72

9 Lesson 5 The Heart Is a Muscle - Worksheet 3 Name: Date: Pd: HEART RATE GRAPH Resting Time (in seconds after exercise) NOTE: To complete the graph, add a label and a value scale to the y-axis. 1. Did you meet your target heart rate? Yes No 2. How long after exercising did you stay within your target heart rate zone? 3. How long after exercising did it take your heart rate to return to its resting rate? 73

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