Name: ______Date: ______

Pulse of Life Lab

Objective:

Students will measure their pulse rate and explore how heart rate is affected by various activities.

Background:

A normal heart receives oxygenated blood entering via the left and right pulmonary veins. Upon contraction, blood is forced out of the left ventricle through the aortic valve and out to the rest of the body. Blood that does not contain oxygen is forced out of the right ventricle through the pulmonic valve and into the lungs.

A pulse is felt because of the flaring of the aorta as the ventricle of the heart flares. Obtaining a pulse rate is important in determining how hard the heart is working and if a bloodflow to a specific limb or body region is normal. The purpose of this experiment is to determine resting heart rate (pulse) in beats per minute and to demonstrate the effects of moderate exercise upon the heart rate.

Key Questions:

How does your heart rate change after exercise?

What can change your heart rate besides exercise?

Materials:

Copy of "Pulse Rate for Different Activities" chart

Clock

Procedure:

  1. Locate your partner’s pulse points either on their wrist or neck. Place you right index and middle finger on the palm side of their left wrist. On the neck, the pulse point is located beneath the ear and jawbone.
  1. Calculate beats per minute. (Count the number of beats in 15 seconds. Multiply this by four (15x4=60, there are 60 seconds in one minute). This is how many times the heart beats in one minute. Enter this "at rest" heart rate on their chart. (Your pulse rate at rest will vary between 60 - 110 beats per minute. Adult rates are lower.)
  2. Do an activity: running in place, jumping jacks, toe touches, meditation, and another exercise of your choice. Stop and calculate your partner’s pulse immediately after the activity for 15 seconds and multiply by four. Calculate their pulse rate again after 3 minutes of rest.
  3. Create a bar graph of the data obtained from the pulse rate running activity. This graph will illustrate the effects of exercise and relaxation on heart rate for both group members.
  1. The x-axis of your graph should be labeled as “Activity” and the y-axis as “Heart Rate (beats/min).
  2. You should include both the resting heart rate and the heart rate taken immediately after the activity for both you and your partner. Be sure to include a key.
  3. Draw a line representing the y value of 80 hearts / min. This value is the average adult resting heart rate. (FYI: An athlete’s average resting heart rate is 50)
  4. Draw line representing the y value of 90 hearts / min. This value is the average adult heart rate after exercise. This value is proportional to the intensity of the exercise.

Name: ______

Group member’s name: ______

Pulse of Life Lab

Pulse Rate
Group Member:
Group Member:
Class Average:
Activity / Pulse Rate Before / Pulse Rate Immediately After / Pulse Rate After 3 Minute Rest
Student’s Initials
At Rest
Running for 2 Minutes
10 Jumping Jacks
10 Toe Touches
Meditation
Activity of your choice:

Questions:

  1. How do the average heart rate for your age group and the average heart rate of the class compare?
  1. What does a pulse measure?
  1. What happened to your pulse after vigorous activity? (Did it increase or decrease?)
  1. What controls the rate of the heart?
  1. How can the heart meet the body’s need for oxygen during activity? (At least 2 things)
  1. What do you think happens to the heart rate after you eat and why?
  1. What do you think happens to the heart rate when you have a fever and why? (Hint: think back to the integumentary system)

Teacher Notes

During each heartbeat, the muscles of the heart contract causing a wave of pressure which forces blood through the arteries. This wave of pressure is known as a pulse. There is one pulsation for each heartbeat. The pulse can be felt at various points on the body where the arteries are just under the skin, such as the temples, neck, crook of the elbow, wrist, groin, back of the knee, and the inside back of the ankle. The normal pulse rate varies with age. Below is a chart listing the range of heart rates and average heart rate for various ages.

With exercise or physical activity, the heart rate increases to supply the muscles with more oxygen to produce extra energy. The heart can beat up to 200 times per minute with extreme exercise. The brain sends nerve signals to the heart to control the rate. The body also produces chemical hormones, such as adrenaline, which can change the heart rate. When we are excited, scared, or anxious our heart gets a signal to beat faster. During a fever, the heart beats faster to bring more blood to the surface of the body to release heat and cool the body. The heart rate increases during and after a meal to send more blood to the digestive system. A trained athlete's heart can pump more blood with each beat so his or her heart rate is slower. Likewise, an athlete's recovery time is shorter.

There are two ways the heart can meet the body's need for oxygen during exercise. It can beat faster or it can beat harder, moving more blood per pump. But it can only beat harder if it has been strengthened through regular exercise.

Range of Heart Rates per Minute and Average Heart Rate for Various Ages

AgeRange Average Rate

0-1 mth 100-180

2-3 mths110-180

4-12 mths 80-180

1-3 yrs 80-160 (130)

4-5 yrs 80-120 (100)

6-8 yrs70-115 (100)

9-11 yrs60-110 (88)

12-16 yrs 60-110 (80)

>16 yrs50-90 (70)

Extensions:

3. Have the students collect pulse rates from various adults and list this on another graph. Calculate the average heart rate for adults. How does this compare with the students' average heart rate?

5. The amount of time the heart takes to return to a normal at-rest rate after exercise is called recovery time. This is a measure of the body's general fitness. The shorter the recovery time, the higher the level of fitness. Determine recovery rate by first measuring and recording the pulse rate at rest. Next, run in place for two minutes. Now measure the pulse rate every minute until the at-rest rate is reached. How long did it take the heart to return to the normal range.

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