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Exercise & circulation physiology slides.ppt
- 1. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 1 1 Circulatory Changes Circulatory Changes During Exercise During Exercise
- 2. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 2 2 Circulatory Changes During Circulatory Changes During Exercise Exercise During exercise there During exercise there is is – Increase demand for Increase demand for energy energy – To meet the increased To meet the increased metabolic demands metabolic demands Demands is met by Demands is met by adjustment of adjustment of – Cardio respiratory Cardio respiratory system system
- 3. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 3 3 Muscle Blood Flow Muscle Blood Flow At rest muscle blood At rest muscle blood flow flow – 3 to 4 ml/ min/ 100 gm 3 to 4 ml/ min/ 100 gm of muscle of muscle During exercise During exercise – 50 to 80 ml /min /100 50 to 80 ml /min /100 gm of muscle gm of muscle Intermittent flow Intermittent flow – Decreases during Decreases during contraction phase contraction phase – Increase between Increase between contractions contractions 40 20 0 0 10 16 18 Bl oo d flo w Minutes Rhythmic exercise
- 4. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 4 4 Circulatory Changes During Circulatory Changes During Exercise Exercise Major effects Major effects occur during occur during exercise exercise – Facilitate adequate Facilitate adequate supply of blood supply of blood required by required by working muscle working muscle include the include the following.. following..
- 5. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 5 5 Circulatory Changes During Circulatory Changes During Exercise Exercise Local mechanisms Local mechanisms Also during Also during exercise there is exercise there is increase increase – Sympathetic Sympathetic discharge discharge – Arterial pressure Arterial pressure – Cardiac output Cardiac output
- 6. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 6 6 Local Mechanisms Local Mechanisms Maintain high Maintain high blood flow in blood flow in exercising exercising muscles muscles Tissue PO Tissue PO2 2 Tissue P Tissue PCO2 CO2 Local Local temperature temperature Metabolites Metabolites
- 7. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 7 7 Local Mechanisms Local Mechanisms Dilatation of Dilatation of – Arterioles Arterioles – Pre-capillary Pre-capillary sphincters sphincters Cause Cause – 10 to 100 fold 10 to 100 fold increase in increase in number of open number of open capillaries capillaries
- 8. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 8 8 Local Mechanisms Local Mechanisms Oxygen consumption Oxygen consumption of skeletal muscles of skeletal muscles 100 fold during 100 fold during exercise exercise This is met by This is met by CO CO Diffusion capacity of Diffusion capacity of lung lung – Opening of capillaries Opening of capillaries
- 9. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 9 9 O O2 2-Hb Dissociation Curve -Hb Dissociation Curve During exercise During exercise The curve shift The curve shift to right to right PH PH Temp Temp 2:3 DPG 2:3 DPG 100 80 60 40 20 20 40 60 80 100 Hb saturation (%) PO2 (mm Hg) 50 27 P50 pH 7.2 pH 7.4
- 10. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 10 10 Local mechanism maintains a high blood flow in exercising muscles Dilation of the arterioles and precapillary sphincters cause a 10-100-fold increase in the number of open capillaries. The capillary pressure increases exceeding the oncotic pressure throughout the length of the capillaries. Lymph flow is also increased limiting the accumulation of tissue fluid Distribution of blood flow at rest and during heavy exercise Oxygen consumption of skeletal muscle increase 100-fold during exercise From Hansen Taher Sherief Physiology book CD
- 11. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 11 11 Sympathetic Discharge Sympathetic Discharge Command signals to Command signals to the muscle the muscle – Relayed to vasomotor Relayed to vasomotor centre centre Sympathetic Sympathetic discharges discharges parasympathetic parasympathetic activity to the heart activity to the heart This causes increase in This causes increase in – HR HR – Contractility of Contractility of myocardium myocardium
- 12. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 12 12 Sympathetic Discharge Sympathetic Discharge Cause constriction of Cause constriction of most of arterioles most of arterioles except except – In active muscles In active muscles Vasodilatation Vasodilatation – Effect of local Effect of local metabolites metabolites Blood is shunted to Blood is shunted to working muscles working muscles Coronary and cerebral Coronary and cerebral vessels vessels – Spared of the Spared of the vasoconstriction vasoconstriction
- 13. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 13 13 Sympathetic Discharge Sympathetic Discharge Constriction of Constriction of capacitance capacitance vessels leads to vessels leads to Mean systemic Mean systemic filling pressure filling pressure Venous return Venous return Cardiac output Cardiac output
- 14. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 14 14 Venoconstriction venous capacity and venous return Command signals to muscles relayed to VMC Symp discharge parasymp HR, Contractility From Hansen Taher Sherief Physiology book CD
- 15. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 15 15 Arterial Pressure Arterial Pressure Arterial pressure Arterial pressure increases during increases during exercise due to exercise due to – Vasoconstriction of Vasoconstriction of arteries & arterioles arteries & arterioles – Increased pumping Increased pumping activity of myocardium activity of myocardium – Increase mean Increase mean systemic filling systemic filling pressure pressure
- 16. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 16 16 Arterial Pressure Arterial Pressure All the above will All the above will tend to increase BP tend to increase BP – (BP = CO x TPR) (BP = CO x TPR) The extent of the The extent of the rise in BP rise in BP – Depend on the type Depend on the type of exercise of exercise performed performed
- 17. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 17 17 Arterial Pressure Arterial Pressure When person perform When person perform exercise under tense exercise under tense conditions conditions – Few areas of Few areas of vasodilatation vasodilatation – Vasoconstriction occurs Vasoconstriction occurs in most tissue in most tissue – TPR increases much TPR increases much more more MAP rises significantly ( MAP rises significantly ( = 170 mm Hg) = 170 mm Hg)
- 18. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 18 18 Arterial Pressure Arterial Pressure When a person When a person performs whole body performs whole body exercise exercise – Running, swimming Running, swimming Rise in MAP Rise in MAP – Not profound Not profound – Large muscle mass Large muscle mass active active Vasodilatation Vasodilatation Lower TPR Lower TPR
- 19. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 19 19 Cardiac Output Cardiac Output Systemic blood flow Systemic blood flow – Increases with increase Increases with increase in intensity of exercise in intensity of exercise CO increases rapidly CO increases rapidly initially then gradually initially then gradually – Until blood flow meets Until blood flow meets metabolic demand for metabolic demand for the exercise the exercise
- 20. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 20 20 Cardiac Output Cardiac Output In sedentary In sedentary people people – CO can increase CO can increase four fold (from 5 to four fold (from 5 to 20 L/ min) 20 L/ min) Mainly by increase Mainly by increase in both in both – HR & SV HR & SV HR can increase up HR can increase up to 190 bpm to 190 bpm SV can increase up SV can increase up to 103 to 113 to 103 to 113
- 21. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 21 21 Cardiac Output Cardiac Output Other factors Other factors Venous return greatly Venous return greatly increased by increased by Activity in working Activity in working muscles muscles Muscle pump Muscle pump Thoracic pump Thoracic pump Mobilization of blood Mobilization of blood from viscera from viscera – Venoconstriction Venoconstriction Mobilization of blood Mobilization of blood from reservours from reservours
- 22. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 22 22 Distribution of CO Distribution of CO Tissue Tissue At rest (ml/min) At rest (ml/min) Strenuous exercise Strenuous exercise (ml/min) (ml/min) Brain Brain 750 (13%) 750 (13%) 750 (4%) 750 (4%) Heart Heart 250 (4%) 250 (4%) 750 (4%) 750 (4%) Muscle Muscle 1,200 (20%) 1,200 (20%) 12,500 (73%) 12,500 (73%) Skin Skin 500 (9%) 500 (9%) 1,900 (11%) 1,900 (11%) Kidney Kidney 1,100 (20%) 1,100 (20%) 600 (3%) 600 (3%) Abdominal viscera Abdominal viscera 1,400 (24%) 1,400 (24%) 600 (3%) 600 (3%) Others Others 600 (10%) 600 (10%) 400 (2%) 400 (2%) TOTAL TOTAL 5,800 5,800 17,500 17,500
- 23. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 23 23 Distribution of CO Distribution of CO 0 10 20 30 40 50 60 70 80 % of CO B r a i n H e a r t m u s c l e s k i n k i d n e y A b d v i s c e r a o t h e r s % of CO distribution at rest and during exercise Rest Exercise
- 24. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 24 24 Local mechanism maintains a high blood flow in exercising muscles Dilation of the arterioles and precapillary sphincters cause a 10-100-fold increase in the number of open capillaries. The capillary pressure increases exceeding the oncotic pressure throughout the length of the capillaries. Lymph flow is also increased limiting the accumulation of tissue fluid Distribution of blood flow at rest and during heavy exercise Oxygen consumption of skeletal muscle increase 100-fold during exercise
- 25. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 25 25 Endurance Athlete Endurance Athlete Resting CO = 5 L/min Resting CO = 5 L/min HR in highly trained HR in highly trained athlete is much lower athlete is much lower – Increased vagal tone Increased vagal tone – Decreased resting Decreased resting sympathetic activity sympathetic activity – HR = 40 to 50 bpm HR = 40 to 50 bpm
- 26. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 26 26 Endurance Athlete Endurance Athlete Resting CO of 5 Resting CO of 5 L/min is achieved L/min is achieved – Increase in SV Increase in SV – (CO = SV x HR) (CO = SV x HR) – (5 = 100 x 50) (5 = 100 x 50) Untrained Untrained – (5000 = 71 x 70) (5000 = 71 x 70) Trained Trained – (5000 = 100 x 50) (5000 = 100 x 50)
- 27. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 27 27 0 50 100 150 200 SVrest HR rest SVex HR ex SV & HR of untrained and trained untrained trained SV & HR in Trained and SV & HR in Trained and Untrained Untrained
- 28. Aug 29, 2024 Aug29, 2024 circulation & exercise circulation & exercise 28 28 Endurance Athlete Endurance Athlete During maximal During maximal excise excise CO of endurance CO of endurance athlete athlete – Can increase up to 35 Can increase up to 35 – 40 L/min – 40 L/min Untrained Untrained – (22,000 = 113 x 195) (22,000 = 113 x 195) Trained Trained – (35,000 = 179 x 195) (35,000 = 179 x 195)