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Physiology, Health & Exercise. Lesson 8 Effect of exercise on CVS. Effect of exercise:. on heart rate cardiac output systolic & diastolic blood pressure recovery time Distribution of blood to tissues during exercise. What happens to heart rate during exercise?.
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Physiology, Health & Exercise Lesson 8 Effect of exercise on CVS
Effect of exercise: • on heart rate • cardiac output • systolic & diastolic blood pressure • recovery time • Distribution of blood to tissues during exercise
What happens to heart rate during exercise? • Heart rate increases in proportion to work done (length & intensity) • CVS must increase its delivery of O2 and nutrients to exercising muscles • Must also remove waste products effectively • Increase blood flow to & from muscles
What happens to heart rate during exercise? • Increase cardiac output • Redistributing the circulation of blood • Cardiac output increased by increasing both HR & SV • Remember CO = HR x SV
How are HR & SV increased? • Increased output from sympathetic nerves to heart increases HR • Increased release of adrenaline into blood which increases HR & SV • Increase in blood volume returning to heart increases rate of filling of heart chambers. Ventricles stretch and contract more forcibly increased SV. SV can increase from 70- 120ml per beat
What happens to blood pressure during exercise? • Systolic blood pressure increases • Can increase from 120- 200 mm Hg • Walls of ventricles working much harder than usual • Diastolic blood pressure remains fairly constant
Effect of exercise on recovery time • What is recovery time? • Regular exercise improves recovery time
Distribution of blood to tissues during exercise • All parts of body require an adequate supply of blood to function efficiently • The demands made by different parts of the body are not equal or constant • At rest vegetative functions are promoted e.g. digestion, urine production • Blood flow diverted to small intestine and kidney • During strenuous exercise blood is diverted to skeletal muscles
Distribution of blood to tissues during exercise • Change in supply of blood to different parts of the body is due to vasodilation (widening) and • vasoconstriction (narrowing) of arterioles supplying these regions.