Physiology And Injuries In Sports — Physical Education STD 12 Commerce — Question
CBSE BoardEnglish MediumSTD 12 CommercePhysical EducationPhysiology And Injuries In Sports5 Marks
Question
Elaborate any five immediate effects of exercise on cardiovascular system.
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Answer
When we do exercises, there are some immediate effects on our cardiovascular system. The immediate effects are stated below.
Increase in Heart Bate: Generally, the resting heart rate of an adult remains at 72 beats per minute. The best endurance athletes usually have 28-40 beats per minute. Even before beginning of exercise the heart rate increases in anticipation. It is known as anticipatory response. When an individual starts exercising, his heart rate increases as per the intensity and duration of the exercise.
Increase in Stroke Volume: Stroke volume is the amount of blood ejected per beat from the left ventricle. It is measured in ml/beat. Stroke volume increases proportionally with intensity of the exercise. In untrained, individuals, the stroke volume at rest remains at 50-70ml/beat. It increases up to 110-130ml/beat during intense exercise. The stroke volume of experienced athletes at rest remains at 90-110ml/beat. It increases up to 150-220ml/beat during intensive exercise.
Increase in Cardiac Output: Cardiac output is the amount of blood pumped by the heart in one minute. It is measured in litre/minute. Cardiac output is a product of stroke volume and heart rate. If either heart rate or stroke volume increases or both, the cardiac output increases also. The cardiac output increases proportionally with the intensity of exercise. At rest the cardiac output is about 5 litre/minute but during intense exercise it can increase up to 20-40 litre/minute.
Increase in Blood Flow: The cardiovascular system can redistribute more blood to those tissues which have immediate demand and less blood to those tissues which have less demand for oxygen. Generally, at rest 15-2O% of the circulating blood is supplied to skeletal muscles. It increases to 80-85% of cardiac output during intensive exercise. Blood is moved away from the main organs such as liver, intestines and kidneys. In fact, it is redirected to the skin to enhance heat loss.
Increase in Blood Pressure: Generally, the systolic blood pressure of a healthy individual ranges from 110-140mmHg and diastolic blood pressure ranges from 60-90mmHg during resting position. During exercise the systolic blood pressure can increase to over 200mmHg. The maximum systolic blood pressure in highly trained athletes have been reported as 250mmHg. Diastolic blood pressure usually remains unchanged even during intensive exercise. If there is an increase of more than 15mmHg as exercise intensity increases, it indicates the presence of coronary heart disease.
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