CARDIOVASCULAR ADJUSTMENTS TO EXERCISE BY : DR FARIHA RIZWAN

CARDIOVASCULAR ADJUSTMENTS

REGULATION OF CARDIOVASCULAR ADJUSTMENTS TO EXERCISE The cardiovascular adjustments at the beginning of exercise are rapid . Within one second after the commencement of muscular contraction there is an increase in sympathetic stimulation of the heart At the same time, there is a vasodilation of arterioles in active skeletal muscles and a reflex increase in the resistance of vessels in less-active areas. The end result is an increase in cardiac output to ensure that blood flow to muscle matches the metabolic needs . What is the signal to "turn on" the cardiovascular system at the onset of exercise? Answer to this question have led us to the development of the central command theory

CENTRAL COMMAND THEORY The term central command refers to a motor signal developed within the brain. The central command theory of cardiovascular control argues that the initial cardiovascular changes at the beginning of dynamic exercise (e.g., cycle ergometer exercise) are due to centrally generated cardiovascular motor signals, which set the general pattern of the cardiovascular response. However, it is believed that cardiovascular activity is modified by heart mechanoreceptors, muscle chemoreceptors , muscle mechanoreceptors, and pressure-sensitive receptors (baroreceptors) located within the carotid arteries and the aortic arch Muscle chemoreceptors are sensitive to increases in muscle metabolites (e.g., potassium, lactic acid, etc) They send messages to higher brain centers to "fine tune" the cardiovascular responses to exercise

Muscle mechanoreceptors (e. g Muscle mechanoreceptors (e.g., muscle spindles, golgi tendon organs) are sensitive to the force and speed of muscular movement These receptors, like muscle chemoreceptors, send information to higher brain centers. Baroreceptors, which are sensitive to changes in arterial blood pressure,send afferent information back to the cardiovascular control center to add precision to the cardiovascular activity during exercise.

WHAT THIS THEORY SUGGESTS ? The central command theory proposes that initial signal to the cardiovascular system at the beginning of exercise comes from Higher brain centers. fine-tuning of the cardiovascular response is accomplished via a series Feedback loops muscle chemoreceptors , muscle mechanoreceptors and arterial baroreceptors

Cardiovascular control during exercise

TIP OF THE DAY

HOW CAN WE MAKE HABBIT OF DOING EXERCISE ON DAILY BASIS???

ANSWER…

IT WAS ALL ABOUT CARDIOVASCULAR RESPONSES TO EXERCISE