My Body: Heart and Blood Circulation

Have you noticed that your heart beats faster when you exercise? Why does it do this? We can answer this question if we take a closer look at the "heart and blood circulation". Your heart pumps blood through your body. Your blood flows through blood vessels. The blood vessels can have two different names. When blood flows away from the heart we call the blood vessel through which the blood flows, the artery. Blood flowing through arteries distributes oxygen and nutrients throughout the body. When the blood returns to the heart it flows through the blood vessel called the vein. It transports waste products out of the body. Our heart pumps blood from the body to the lungs, where the blood can exchange carbon dioxide for oxygen. The fresh and oxygenated blood is pumped back into the arteries by the heart. That's why we call it blood circulation. The heart pumps blood over and over again through arteries to every corner of your body and back again through veins. When the heart pumps, it beats. We can feel the beating of the heart outside on the walls of the veins. We call the repeating beats of the heart the pulse. Now let's try a little experiment: You need a stopwatch, a pen, and paper. Now you can use your index and middle fingers to find a spot on your forearm or your neck where you can feel your pulse with your fingertips. The experiment is divided into two parts. In the first part, which you are about to do, count the beats of your heart for fifteen seconds. Then write down the number of beats you counted. Press pause on this video and start NOW! What did you write for your result? Now you have to do a quick calculation and multiply the number of your beats by FOUR. For example, if we counted twenty beats, multiply it by four to equal eighty beats per minute. This is how you determine how often your heart beats per minute. You have just measured your heart rate at rest because you probably did not move much beforehand. Now comes the second half of the experiment. You're about to do twenty squats, THEN sit down and count the number of beats again for fifteen seconds. Don't forget to write it down! You can pause the video and start NOW. Out of breath? Did you write your result? Also, multiply YOUR new result by four. We measured thirty-five beats, so we get one hundred and forty beats per minute. Did you notice anything about your result? At rest, your heart beats slower. When you're exerting yourself, your body needs more oxygen and nutrients than when it's resting. When you measured AFTER the squats, your heart should have been beating faster. Because your heart has to pump more blood. So what can we say about the heart and the bloodstream? Our blood flows in a blood circuit. The arteries lead away from the heart. In systemic circulation, the blood in the arteries is full of oxygen and nutrients. Blood with used substances flows towards the heart through veins. When you measure your beating heart, we call it your pulse. You can feel it on certain parts of your body with your fingertips... because our blood nourishes our body, the heart beats faster when we exercise. Did this video make your heart beat faster? Tell us in the comments. Until next time!