Cardiovascular System6

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Cardiovascular System6

  1. 1. CVS changes during Exercise <ul><li>The Cardiovascular system changes to match supply and demand. </li></ul><ul><li>Components of the CV system during exercise </li></ul><ul><ul><li>heart rate </li></ul></ul><ul><ul><li>strove volume </li></ul></ul><ul><ul><li>cardiac output </li></ul></ul><ul><ul><li>blood flow </li></ul></ul><ul><ul><li>blood pressure </li></ul></ul>
  2. 2. Heart rate <ul><li>Measure at the radial or carotid site. </li></ul><ul><li>Reflects the amount of work that it is performing to meet the demands of the body with increasing work. </li></ul><ul><li>Resting HR: 60 to 80 bts/min. </li></ul><ul><ul><li>Anticipatory response-prior to starting exercise just knowing that you are going to have to start exercise. </li></ul></ul><ul><ul><li>220-age= predicted Max HR. </li></ul></ul>
  3. 5. Change in HR during Exercise <ul><li>As exercise begins, Para-SNS withdraws influence. </li></ul><ul><li>SNS stimulates heart. </li></ul><ul><li>Adrenal gland secretes catecholamines. </li></ul><ul><li>Increase in body temperature ,as in intense exercise. </li></ul>
  4. 6. Stroke Volume  May increase with increasing rates of work up to intensities of 40% to 60% of maximum exercise.  May continue to increase up through maximal exercise intensity, generally in highly trained athletes <ul><li>Depends on position of body during exercise </li></ul><ul><ul><li>upright-SV is less, supine is greater (easier to heart) </li></ul></ul>
  5. 7. STROKE VOLUME
  6. 8. Cardiac Output <ul><li>Resting is 5.0 L/min- </li></ul><ul><li>20 to 40 L/min during exercise. </li></ul><ul><li>The need for an increase is to meet the muscle’s demands during exercise. </li></ul><ul><li>An increase in HR and SV increases Q, (separate or together) </li></ul><ul><li>After 40 to 60% of max, SV plateaus, Q increases due to increase in HR . </li></ul>
  7. 9. CARDIAC OUTPUT
  8. 11. Redistribution of Blood Flow <ul><li>Blood flow to tissues is controlled in relation to tissue needs </li></ul><ul><ul><li>Tissue needs may  20-30 fold, but cannot  Q that much: 5 L/min  100 -150 L/min ! ? So flow is redistributed between tissues </li></ul></ul><ul><li>Muscle blood flow  to working skeletal muscle </li></ul><ul><li>Splanchnic blood flow  to less active organs </li></ul><ul><ul><li>Liver, kidneys, GI tract, & also to non-working muscle </li></ul></ul>
  9. 12. Redistribution of Blood Flow During Exercise
  10. 13. Redistribution of Blood Flow Local Systemic Vasodilation Vasoconstriction <ul><li>PO2 </li></ul><ul><li>PCO2 </li></ul><ul><li>[H+] </li></ul><ul><li>adenosine </li></ul><ul><li>[K+] </li></ul><ul><li>Nitric oxide </li></ul>Metabolites Epinephrine Adrenal medulla Sympathetic Nervous System overrides
  11. 14. Blood pressure during endurance activities <ul><li>SBP increases in proportion to exercise intensity. </li></ul><ul><li>DBP changes very little during endurance exercise. </li></ul><ul><li>There is modest increase in mean arterial pressure . </li></ul>
  12. 15. Effects of Incremental Exercise on BP
  13. 16. Cardiovascular Adjustments to Exercise
  14. 17. Cardiac Output Components in Trained & Untrained Subjects Untrained Rest 70 72 5.0 Max Exercise 195 113 22.0 Endurance Trained Rest 50 100 5.0 Max Exercise 195 179 35.0 Heart rate Stroke volume Cardiac output Subject/Activity (beats/min) (ml/beat) (L/min)

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