Slide 1What is Cardiorespiratory fitness?Cardiovascular systemSlide 4Slide 5How do we measure cardiorespiratory fitness?How to measure aerobic fitness?VO2max ProtocolsVO2max ProtocolsHow do you know if they’re at max?How do you know if they’re at max?Slide 12Other ways to measure aerobic fitnessField testsWhat limits VO2max?What limits VO2max?What limits VO2max?Advantages/disadvantages VO2max testAdvantages/disadvantages prediction testsSummaryCardiorespiratory FitnessKIN 247Fall 2017What is Cardiorespiratory fitness? •Cardiorespiratory (aerobic) fitness – attribute or characteristic, endurance, ability to sustain work for a long period of time•Indicator of overall health–Inversely related to all-cause death, heart disease & CHF death, diabetes, etc..–1 MET increase in fitness= 10% decrease in mortality –Prevention to chronic disease •Can be used to monitor training progressWhat allows us to sustain work??-Supply oxygen to skeletal muscles-Respiratory system, heart, blood vesselsCardiovascular system•The heart pumps de-oxygenated blood to the lungs •The oxygenated blood returns from the lungs•The heart pumps oxygenated blood to the muscles•The heart receives de-oxygenated blood from the musclesDeterminants of Proper Oxygen TransferHow do we measure cardiorespiratory fitness? VO2 – The volume of oxygen consumed during physical activity.–Measured in ml O2/kg/min–Indirect Calorimetry–Direct Fick method –VO2= cardiac output x a-VO difference1MET=1kcal/kg/hr = 3.5ml O2/kg/minHow to measure aerobic fitness?VO2max: Maximal oxygen consumption test–Indirect calorimetry–Cycle ergometer (increase load)–Treadmill: Increase speed and/or incline gradually– measure ventilation, carbon dioxide and oxygen using metabolic cartVO2max ProtocolsVO2max ProtocolsHow do you know if they’re at max? Criteria to define “max” 1) HR within 15 beats of age predicted max HR - 220- age2) No further increase in VO2 with increase in workload3) RPE > 17- rate of perceived exertion 4) Respiratory exchange ratio (RER) of 1.1 or greaterHow do you know if they’re at max? VO2 “peak”–highest VO2 achieved during a test•test was not performed to max effort •VO2 still increasing when test stoppedVO2max in ml/kg/minOther ways to measure aerobic fitness1) Sub-maximal test–Similar to max test but only take people to sub-max and then predict based on heart rate2) Time on treadmillVO2Heart Rate80%100%Field tests3) Timed 1-mile–Prediction equation based on how long it takes to walk a mile (Rockport Walk test)4) Step test–16” step, take ~ 22 steps/minute. Predict based on HR5) Non- exercise prediction equationWhat limits VO2max?1) Cardiac Output–L/min–Heart rate (beats/min) X stroke volume (ml/beat)•HR ~ 60 beats/min•SV ~ 70 ml/beat•CO ~ 4200 ml/min – 5 L/min @ rest– L/min @ exerciseWhat limits VO2max?2) a-vO2 difference–difference in O2 between arterial & venous O2–ml O2/100ml blood–@ rest: a-vO2 ~ 5 ml/100ml blood•arterial = 20 ml/100ml, venous = 15 ml/100ml–@ exercise: a-vO2 =~16 ml/100ml!•arterial = 20 ml/100ml•venous = 4 ml/100mlWhat limits VO2max?3) Oxygen uptake in the lung-hemoglobin, iron-mechanical limitation 4) Oxygen Delivery-distribution of cardiac output5) Oxygen Usage-mitochondrial dysfunctionAdvantages-Objective-Direct measure of oxygen consumption -accurateDisadvantages-The need for special, expensive equipment and trained administrators-Maximal testing is riskier than submaximal testing -A high level of motivation on the part of the subject is necessary Advantages/disadvantages VO2max testAdvantages•Objective •Can be inexpensive •Short duration •“more safe” due to submax effortDisadvantages•Max HR and BP are not necessarily measured •Oxygen consumption may not be measured depending on the test Advantages/disadvantages prediction testsSummary•What is cardiorespiratory fitness?•How do you measure it?–VO2max test –Sub max tests–Field tests•What is VO2max?–What contributes/limits VO2max?•Advantages/Disadvantages to max, sub-max and field testing for cardiorespiratory