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The Cardiovascular System: How Exercise Makes it Hum
Exercise can be a little tough when you start out. Take inspiration during your next workout by understanding the good it’s doing inside with Groupon’s whirlwind tour of the cardiovascular system.
The average person’s heart beats 100,000 times a day, pushing 10 pints of blood all the way to the tips of the toes and back through 60,000 miles of vessels. Along this route, that blood stops to do a great many errands. The heart pumps blood to the lungs to collect oxygen before sending it through the rest of the body via arteries, arterioles, and capillaries. Once the tissues have absorbed the oxygen and nutrients they need, they send the waste-filled blood back to the heart through the veins to be reoxygenated and start the process again.
Every time our heart beats, what we really feel is the opening and closing of valves that push the blood through the heart’s four chambers and out to the body. When we exercise or get scared by a shrub that looked like a huge dog for a second, our brains instruct the heart to beat harder to supply the body with what it needs to fight or run. As exercise enhances the muscles over time, it also improves the function of the entire cardiovascular system.
This happens in several ways. Although exercise makes the heart work harder in the short term, this ultimately causes the body to adapt, easing the heart’s everyday tasks. In response to muscles’ demand for more oxygen and compliments, the body actually sprouts new capillaries, while prompting existing capillaries to open wider. These increased channels help lower blood pressure, since blood now encounters less resistance on its way to the extremities. The heart also becomes better at oxygenating the tissues—red blood cells increase their numbers during intense exercise.
With its insistent knocking in our ribcage, you may think the heart’s role in all this would be hard to ignore. But the earliest anatomists didn’t hear its call so clearly. Galen and Hippocrates believed the liver produced blood and spread it through the body in a centrifugal manner; meanwhile, the veins contained air, which the lungs pushed to the tissues. They also assumed this was an open-ended system, with the blood and air gradually dissipating when it reached the ends of veins and arteries—a view that would hold for another 1,500 years.