Functional Capacity of the Cardiovascular System Chapter 17 Functional Capacity of the Cardiovascular System Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Cardiac Output Cardiac output (Q) = HR × SV Methods of Measuring Q Direct Fick Indicator dilution CO2 rebreathing Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Direct Fick Method a- O2 difference Q = O2 mL · min−1 Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Indicator Dilution Method Q = Quantity of dye injected Average dye concentration blood × Duration of curve for duration of curve Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

CO2 Rebreathing Method -aCO2 difference Q = CO2 × 100 Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Cardiac Output at Rest Values vary depending upon emotional state. Average male ~5 L · min-1 Average female ~4 L · min-1 Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Untrained Characteristics of Q HR ~ 70 BPM SV ~ 71.4 mL Average women ~25% lower due to smaller size Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Endurance Athletes Characteristics of Q Mechanisms HR ~ 50 BPM SV ~ 100 mL Mechanisms Increased vagal tone w/decreased sympathetic drive Increased blood volume Increased myocardial contractility and compliance of left ventricle Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Cardiac Output During Exercise Q increases rapidly during transition from rest to exercise. Q at max exercise increases up to 4 times. Q HR SV Untrained 22 L 195 113 mL Trained 35 L 195 179 mL Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Stroke Volume: Diastolic Filling vs. Systole Emptying Mechanisms for increased SV with training Increased blood volume – increase diastolic filling Increased preload – Starling’s Law of the Heart Increased Contractility – greater systolic emptying Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Cardiovascular Drift Results from HR drifts upward to maintain same Q Dehydration Reduction in SV HR drifts upward to maintain same Q Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Cardiac Output Distribution Blood flows to tissues in proportion to their metabolic activity. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Cardiac Output and Oxygen Transport Rest Q = 5 L · min-1 O2 transport = 1,000 mL – 200 mL/L blood Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Exercise Max Q averages ~ 16 L · min-1 O2 transport = 200 mL/L blood Result 3200 mL O2 Training enables Q to increase up to 40 L · min-1, increasing O2 transport up to 8,000 mL. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Close Association Between Max Q and O2max An almost proportionate increase in max Q accompanies increases in O2max with training. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Cardiac Output Differences: Men, Women, and Children Women have a 10% lower hemoglobin level than men. Result is a 5 – 10% increase in Q at any submax level of O2 consumption Children have higher HR Result is smaller Q, expanded a- O2 Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

O2 Extraction: The a- O2 Difference O2 consumption increases during exercise. Increases Q Increases extraction of O2 by tissues O2 = Q x a- O2 difference Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

a- O2 Difference during Rest 20 mL O2 · dL-1 arterial blood 15 mL O2 · dL-1 venous blood 5 mL a- O2diff Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

a- O2 Difference during Exercise 20 mL O2 · dL-1 arterial blood 5 – 15 mL O2 · dL-1 venous blood Up to a threefold increase in O2 extraction Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Severe Heart Disease Exhibit low ability to improve Q or SV Skeletal muscle adaptations allow for increased O2 extraction. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Factors Affecting the a- O2 Differences Redistribution of flow to active tissues during exercise Increased capillary density due to training increases surface area and O2 extraction Increased number and size of mitochondria Increased oxidative enzymes Vascular and metabolic improvements Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Cardiovascular Adjustments to Upper-Body Exercise Max O2 consumption Upper-body exercise results in max O2 consumption ~20 – 30% lower than lower-body exercise. Higher O2 consumption for a given submax workload Lower mechanical efficiency Muscular effort to stabilize torso Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Physiologic Response Submaximal arm exercise produces > HR > Pulmonary ventilations > RPE > BP response than comparable leg exercise Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

Physiologic Response Exercise prescription for arm exercise should not be based on values obtained from lower-body exercises. Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition