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Lack of regular exercise increases the risk of heart diseasebecause: A) the thre

ID: 3761 • Letter: L

Question

Lack of regular exercise increases the risk of heart diseasebecause: A) the threshold of the sna node is increased, so the durationof the cardiac cycle is lengthened B) Blood flows too slowly over time to provide adequate oxygento the myocardium C) the valves lose tone, and don't close securely D) pumping efficiency decreases because as stroke volumedecreases, heart rate must increase to maintain cardiacoutput E) respiratory rate is too low to take in sufficient oxygenfor optimal oxygenation of the blood. Lack of regular exercise increases the risk of heart diseasebecause: A) the threshold of the sna node is increased, so the durationof the cardiac cycle is lengthened B) Blood flows too slowly over time to provide adequate oxygento the myocardium C) the valves lose tone, and don't close securely D) pumping efficiency decreases because as stroke volumedecreases, heart rate must increase to maintain cardiacoutput E) respiratory rate is too low to take in sufficient oxygenfor optimal oxygenation of the blood.

Explanation / Answer

The correct answer is D. This is due to the factthat without exercise, the heart like any other muscle in the bodybecomes weak. As the ventricular muscles of the heart weaken, theymust work harder with every pump to circulate enough volume ofblood around the body. Over time this puts a lot of strain on theheart and also causes damage to the blood vessels near theheart(such as the aorta) and causes the production of platelets torepair the arteries which can lead to platelets sticking togetherand clogging the arteries.