cardiopulmonary changes in exercise

This PPT describes about both acute and long term effects of exercise on cardiovascular and respiratory systems.

1. Cardiopulmonary changes in Exercise Dr Rajesh P Associate Professor Department of Physiology Mediciti IMS

2. Introduction Exercise is physical activity that is planned, structured and repetitive for the purpose of conditioning any part of the body . Exercise is used to improve health, maintain fitness  and is i mportant  as a means of physical rehabilitation.

3. Primary aim of the exercise In the heart: to supply adequate oxygenated blood to the exercising muscle In the lungs: to facilitate oxygen consumption of the body - To meet the metabolic demand during exercise.

4. Types of exercise Flexibility. E: shoulder and upper arm stretch, calf stretch Endurance. E: brisk walking, jogging, swimming Strength. E: lifting weights Balance. E: standing on one foot, heal-to-toe walk

5. Grading of exercise Grade Level HR(beats / min) O2consumption(L/min) I Light (mild) < 100 0.4 – 0.8 II Moderate 100 - 125 0.8 – 1.6 III Heavy 125 – 150 1.6 – 2.4 IV Severe >150 >2.4

6. Changes during exercise Training effects are the physiological changes your body makes in response to the demands of the exercise you perform. There are 2 kinds of responses to training: Acute (immediate) – last only for the duration of the exercise & the recovery period . Chronic – long-term adaptations & take about 6 weeks of training to develop.

7. Changes in exercise Systems CVS RS Short term Short term Long term Long term

8. CVS Short term Long term Increased HR, BP Cardiac hypertrophy Increased SV, CO Increased skeletal muscle blood flow Redistribution of blood flow Lower resting heart rate Increase in RBCs, Capillaries

9. RS Short term Long term Increase in RR, TD Increased ventilation Increased ventilation Increased lung capacity Increased VO2 Increased strength of intercostal muscles Increased oxygen diffusion rate Increased minute ventilation Increased number of capillaries and alveoli Increased lactate threshold

10. CVS Responses to exercise Skeletal muscle blood flow Redistribution of blood flow Cardiac output changes Blood pressure changes Blood volume changes

11. Cardiovascular Response to Exercise Increased heart rate / cardiac output Anticipatory response (increased heart rate before exercise) Caused by the release of epinephrine Steady state heart rate : during steady exercise Maximum heart rate = 220 - age

12. Skeletal muscle blood flow Blood flow increased by arteriolar dilatation and opening up of closed capillaries. Local factors: autoregulation Neural factors: sympathetic Humoral factors: adrenaline Sympatho – adrenaline discharge induces an increase in muscle blood flow in anticipation of exercise and adrenaline sustains the increased blood flow during and beyond the exercise.

13. Redistribution of Blood Flow During Exercise Increased blood flow to working skeletal muscle At rest, 15–20% of cardiac output to muscle Increases to 80–85% during maximal exercise Decreased blood flow to less active organs Liver, kidneys, GI tract Redistribution depends on metabolic rate Exercise intensity

14. Redistribution of blood to the skin in order to maintain body temperature . Increased metabolic rate of working muscles Autoregulation: intrinsic control of blood flow by changes in local metabolites (e.g., oxygen tension, pH, potassium, adenosine, and nitric oxide) around arterioles. Cardiovascular drift: increased H.R. compensates for a decreased S.V. from a decreased total blood volume to maintain Q. redistribution decreased blood plasma

15. Redistribution of Blood Flow During Exercise

16. Changes in Muscle and Splanchnic Blood Flow During Exercise

17. Regulation of Local Blood Flow During Exercise Skeletal muscle vasodilation Autoregulation Blood flow increased to meet metabolic demands of tissue Due to changes in O 2 tension, CO 2 tension, nitric oxide, potassium, adenosine, and pH Vasoconstriction to visceral organs and inactive tissues SNS vasoconstriction

18. Oxygen Delivery During Exercise Oxygen demand by muscles during exercise is 15–25x greater than at rest Increased O 2 delivery accomplished by : Increased cardiac output Redistribution of blood flow From inactive organs to working skeletal muscle

19. Changes in Cardiac Output During Exercise Cardiac output increases due to: Increased HR Linear increase to max Increased SV Increase, then plateau at ~40% VO 2 max No plateau in highly trained subjects Max HR = 220 – age (years)

20. Stroke Volume

21. Heart rate Increased heart rate Anticipatory response (increased heart rate before exercise) Caused by the release of epinephrine Steady state heart rate: during steady exercise

22. Cardiac output No change at rest No change at submax exercise Increased at maximal exercise

23. The cardiac c ycle at rest and d uring e xercise

24. Changes in Arterial-Mixed Venous O 2 content d uring e xercise Higher arteriovenous difference (a-vO 2 difference) Amount of O 2 that is taken up from 100 ml blood Increase due to higher amount of O 2 taken up Used for oxidative ATP production Fick equation Relationship between cardiac output (Q), a-vO 2 difference, and VO 2 VO 2 = Q X a-vO 2 difference

25. Blood Pressure SBP increases in direct proportion to increase in exercise intensity As exercise begins the baroreceptors detect a decrease in BP specifically SBP The CNS responds by constricting blood vessels and increasing SBP and further increases HR Eventually the CNS detects that SBP needs to be reduced and is reduced via the vasodilation of the vessels. The CNS will continue to attempt to regulate BP throughout exercise until maximal levels are reached DBP does not change significantly (may even decrease) Therefore little change in MAP

26. Blood pressure r esponse to exercise Systolic- Maximum pressure Diastolic- Minimum pressure

27. Isotonic exercise

28. Isometric exercise

29. BP changes in Exercise Systolic B.P. increases with intensity V alsalva during resistance exercise (moderately forceful attempted exhalation against a closed airway, usually done by closing one's mouth, pinching one's nose shut while expelling air out as if blowing up a balloon ) increased use of upper body musculature Diastolic B. P. does not change

30. Changes in Blood volume Increased total blood volume Increased plasma volume Increased red blood cells Decrease in hematocrit (44 to 41)

31. Myocardial Hypertrophy Aerobic training: Thicker walls and greater volume Strength training: Thicker walls only Pathological: Thicker but weaker walls

32. Transition from r est to e xercise and exercise to recovery At the onset of exercise: Rapid increase in HR, SV, cardiac output Plateau in submaximal (below lactate threshold) exercise During recovery Decrease in HR, SV, and cardiac output toward resting Depends on: Duration and intensity of exercise Training state of subject

33. Transition From Rest to Exercise to Recovery

34. Summary of Cardiovascular Responses to Exercise

35. Acute cardiovascular responses to exercise  heart rate  stroke volume  cardiac output  blood pressure  blood flow  blood plasma volume

36. Long-term effects of exercise - Heart Larger, stronger heart chambers Stronger heart beat – more efficient circulation Lower resting heart rate – greater capacity for work Stroke volume – can be double that of an untrained athlete Cardiac output – larger stroke volume increases the blood processed per minute

37. Circulatory system Arteries become larger and more elastic Blood pressure reduced More red blood cells produce more haemoglobin Lower levels of fat in the blood as the body has learned to utilise it as fuel Increased capacity to process lactic acid during exercise

38. Respiratory changes in exercise

39. Before expected exercise begins, ventilation rises 'emotional hyperventilation ‘ at any rate, impulses descending from the cerebral cortex are responsible

40. How does pulmonary ventilation (breathing) increase during exercise? During light exercise (walking)? By increasing the tidal volume (breathing deeper) During intense exercise (sprinting)? By increasing the frequency of breathing During steady state exercise (jogging)? By increasing both the tidal volume and the frequency of breathing

41. during dynamic exercise of increasing intensity, ventilation increases linearly over the mild to moderate range, then more rapidly in intense exercise the workload at which rapid ventilation occures is called the ventilatory breakpoint (together with lactate threshold) Respiration during exercise Lactate acidifies the blood, driving off CO2 and increasing ventilatory rate

42. F actors which stimulate increased ventilation during exercise neural input from the motor areas of the cerebral cortex proprioceptors in the muscles and joints  b ody temperature circulating NE and E pH changes due to lactic acid changes in pCO 2 and O 2 do not play significant role during exercise

43. Lung volumes

44. Lung capacities

45. Immediate changes during exercise on RS a) Tidal Volume: increases depending on intensity, it may be 1500-2000 ml for ordinary person and for well trained athlete it may be increased to 2500 ml. b) Respiratory rate: for ordinary persons it may be increased to 25-30 per minute and for well trained athlete it may be around 38-40 per minute. c) Pulmonary Ventilation: both TV and RR increases , PV will also increase depending on the intensity of exercise . For ordinary person , the value of PV may be 40-50 lit / min and for well trained athlete , it may be around 100 lit / min.

46. d) Oxygen uptake: The amount of oxygen which we take inside the body from ambient air in each minute at rest is called resting oxygen uptake. It is around 200-300 ml / min . During exercise oxygen uptake increases to 3.5 lit / min for ordinary person and 4.5 lit/min for well trained athlete. .

47. e) Lung diffusion capacity: During exercise there will be more movement of gas molecules and diffusion capacity increases. f) Lung volume: For normal breathing at rest lung expand and there is a change in air pressure. During exercise due to rapid movement of diaphragm and intercostal muscles total area of lung expands to accommodate more exchange of gases

48. Long-term effect of training on RS Tidal Volume (TV) : Trained athlete’s capacity to inhale or exhale air during exercise increases to the tune of 2500 ml. Untrained persons can not increase up to this level because their capacity is less than trained athletes. b) Respiratory rate (RR) : Trained athlete may increase their rate to 40 in each minute from 16 / min at rest. Untrained persons will not be able to reach to this level . They may increase their rate up to 25-28 / min.

49. c) Pulmonary ventilation (PV): A trained athlete may increase PV to around 100 lit/min. This is because their TV and RR both increases during exercise. Untrained persons may increase it up to 50-60 lit/min. d) Oxygen uptake: During exercise, after a long term training , a trained athlete may consume around 5 lit oxygen per minute. Untrained persons may go up to the level of 3.5 lit oxygen per minute.

50. e) Lung diffusion capacity: During exercise , the lung diffusion capacity increases in both trained and untrained persons. However, trained athletes may increase their diffusion capacity 30% more than that of an untrained person because athlete’s lung surface area and red blood cell count is higher than that of the non-athletes. f) Vital capacity: For a healthy adult male it is around 4.8 lit and for women 3.1 lit. The athletes who are under training for a long period may increase vital capacity to around 6 lit.

51. g) Efficiency of lung: An athlete’s total efficiency of the lung remain at higher level than the non-athletes. This efficiency is the key factor for higher rate of oxygen uptake than non-athletes. h) Second wind: a sudden transition from an ill-defined feeling of distress or fatigue during the early portions of prolonged exercise to a more comfortable, less stressful feeling later in exercise. It has been observed that trained athletes get their second wind comfortably and easily than non-athletes.

52. VO2 max the maximal amount of oxygen that the human body is able to utilize per minute of strenuous physical activity T he intensity of exercise performed is defined as a percentage of VO 2max  50% of Vo 2max – glycogen use less than 50%, FFA use predominate + small amounts of blood glucose >50% of Vo 2max – carbohydrate use increases  glycogen depletion  exhaustion

53. 70-80% of Vo 2max – glygogen depletion after 1.5-2 hrs 90-100% of Vo 2max – glycogen use is the highest, but depletion does not occur with exhaustion ( pH and  of metabolites limit performance)

54. Oxygen consumption (liters/min) V 2 peak Work rate (watts) ↑ exercise work  ↑ O 2 usage  Person’s max. O 2 consumption ( V O2max ) reached

55. Acute respiratory responses to exercise During exercise & recovery, more O2 must be delivered from the lungs to the working muscles, & excess CO2 must be removed from the working muscles.  respiratory rate  tidal volume  ventilation  lung diffusion  O2 uptake, or volume of O2 consumed

56. L ong term effects on Breathing Lung capacity increased Increased number of alveoli in lungs This allows a greater volume of air to pass into blood stream We can therefore maintain higher levels of activity for longer and are less likely to become breathless when performing normal daily tasks Gaseous exchange is improved so that CO2 and other waste products are removed more efficiently. This also improves our anaerobic capacity

57. Cardiorespiratory endurance the ability of the heart, lungs and blood vessels to deliver adequate amounts of oxygen to the cells to meet the demands of prolonged physical activity the greater cardiorespiratory endurance  the greater the amount of work that can be performed without undue fatigue the best indicator of the cardiorespiratory endurance is VO 2max .

58. Benefits of exercise