Why does your heartbeat increase when you run? long answer
Answers
Answer:
Your heart is a muscle, and gets a workout during exercise. Its job is to get more blood out to the body's muscles when they work hard.
When you are exercising, the heart's blood flow increases by around four or five times from when you are at rest. Your body does this for you by increasing the rate of your heartbeat, thus increasing the amount of blood that goes out to the rest of the body.
Cardiac output is the rate of blood pumped by the heart. You get that from multiplying the heart rate, the rate at which the heart beats, by the stroke volume, which is the volume of blood ejected by the heart with each beat. When you are at rest, the cardiac output is about 5 liters a minute. With exercise, sympathetic nerves stimulate the heart to beat faster and more forcefully; the heart rate can actually increase about threefold.
At the same time the veins constrict due to the sympathetic nerve stimulation. More blood being returned from the working muscles, along with the vein constriction, increases the venous return, or the amount of blood returned to the heart. This increased venous return increases the stroke volume by about 30 to 40 percent.
When the heart pumps at full force, the cardiac output can be about 20-25 liters per minute.
Answer:
Because, Our body needs more oxygen but, we can't get proper oxygen because, the value of oxygen is only 21%