April 24, 2020
Measure Your Heart Rate
Learn about the habits of the heart by measuring your heart rate
During this time at home, it’s important to find time to be active as well as some time to be mindful about relaxing, both of which keep our hearts healthy.
In today’s activity, learners will use the scientific method to get to know their heart rate better under different circumstances.
Our heart is a muscle whose job it is to send blood all over your body, carrying important nutrients and oxygen. Each time your heart pumps blood, it first needs to fill up with blood, then it contracts (or squeezes) to send the blood out of the heart and to the rest of your body. This is known as a heartbeat.
You can feel this heartbeat throughout your body anywhere there is a large artery (blood vessel that takes blood away from your heart) close to your skin, because the rush of blood flowing from your heart through your arteries causes them to expand and contract,. We feel this as our pulse.
The best places to take your pulse are your wrist, just below your thumb and at your neck, though you also can feel your pulse in many other places, including your ankle!
Our heart rate (how often your heart beats in a minute) varies depending on many things, such as whether you are active or resting, calm or stressed, hot or cold. Our resting heart rate, which is our average heart rate when we are not active, can tell us a lot about the strength of our heart. Generally, people with stronger hearts have a lower heart rate because their hearts don’t need to beat as often to pump blood through their bodies.
Just like other muscles in our bodies, it is important to exercise our heart regularly in order to keep it strong and healthy, but it is just as important to give our heart plenty of time to relax.
Today we will design an experiment to test the effect of different activities on your heart rate.
This activity includes about 5 minutes of preparation and 10-30 minutes of preparation. It is suited well for all ages.
- Space to exercise
- Space to rest
- Headphones and music (optional)
Finding your Pulse
1. Decide where you are going to find your pulse. Remember, the best places to find your pulse are on your neck and your wrist. Pick wherever is easiest to feel your pulse.
Measuring your Resting Heart Rate
2. Make sure you are in a comfortable position, find your pulse, and count how many times your heart beats in 15 seconds. Set a timer on your watch or phone or have someone else time you.
3. Now it’s time for a little math. Remember that your heart rate is how many times your heart beats in 1 minute, or 60 seconds. You counted for 15 seconds so you’ll need to multiply the number you came up with by 4. For example, let’s say you counted 25 beats in 15 seconds:
25 beats x 4 = 100 beat per minute (bpm)
Your resting heart rate would be 100 bpm. Alternatively, you could also use a heart rate tracker, if you have one, but doing math is fun!
Time to Experiment
1. Decide what you want to test. This is known as our variable. Do you want to jog in place for one minute? Take a lap around your backyard? Do 15 squats? Once you’ve decided on what you’re going to test, make a hypothesis, or prediction. What do you think is going to happen to your heart rate when you complete your activity?
2. As soon as you’ve completed your activity, measure your heart rate again and write it down. You can make a chart like the one below to record your data.
3. A good scientist always tests their experiment more than once. Let your heart rate come down to resting again and repeat your experiment. Did you get the same results?
4. Choose a different type of activity to test. What happens to your heart rate when you take 10 deep relaxing breaths? Meditate for 5 minutes? Listen to your favorite song on headphones? There are so many different variables you can test, so have fun experimenting!
How to adjust for younger an older learners
For younger learners, instead of counting, focus on general heart rate changes. Ask your young scientist if they felt their heart rate go up or down. Alternatively, you can visualize their pulse. All it takes is a small amount of playdough and a toothpick. Place the small piece of playdough with the toothpick securely attached on one of the pulse points (wrist or ankle work best for this). Stay as still as possible and watch the pulse move the toothpick!
For older learners, test your variables at least three times and calculate an average heart rate. In order to find the average, add up your heart rate measurements, and divide by the number of times you took the measurements. You can also test your heart rate over the course of multiple days, and graph any trends, just make sure you’re testing the same variables every time.