Chapter6

• 1.Cardiorespiratory Endurance Chapter 6

2. Objectives Define cardiorespiratory endurance and describe thebenefits of cardiorespiratory endurance training inmaintaining health and well-being. Define aerobic and anaerobic exercise, and giveexamples. Be able to interpret the results ofcardiorespiratory endurance assessments according tohealth fitness and physical fitness standards. Explain the principles that govern cardiorespiratoryexercise prescription: intensity, mode, duration, andfrequency. Learn some ways to foster adherence to exercise. Assess your cardiorespiratory endurance. Maintain a log ofall your fitness activities. 3. Introduction Most important component of health-relatedphysical fitness However, older adults primarily need strength Cardiorespiratory (CR) endurance activitiesconditions the CV system and helps a personachove and maintain a healthy weight Physical inactivity and our natural existenceleads to Hypokinetic diseases Hypertension, obesity, heart disease, LBP 4. Basic CardiorespiratoryPhysiology CR endurance The ability of the lungs, heart, and bloodvessels to deliver adequate amounts ofoxygen to the cells to meet the demands ofprolonged physical activity 5. Basic CardiorespiratoryPhysiology Adenosine triphosphate (ATP) a high-energy chemical compound that the bodyuses for immediate energy Oxygen is used to convert food substrates(carbohydrates and fats) through aerobicmetabolism into ATP ATP provides the energy for physical activity,body functions, and maintenance of constantinternal equilibrium (homeostasis) During physical exertion, the lungs, heart, andblood vessels have to deliver more oxygen to themuscle cells to supply ATP 6. Basic Cardiorespiratory Physiology As a person breathes, part of the oxygen in theair is taken up by the air sacs (alveoli) in thelungs As blood passes through the alveoli, oxygen ispicked up by an iron-containing compound(hemoglobin) and transported in the blood tothe heart The heart pumps the oxygenated blood throughthe circulatory system to all organs and tissuesof the body 7. Basic CardiorespiratoryPhysiology 8. Aerobic and AnaerobicExercise Aerobic exercise: Exercise that requires oxygen toconvert lipids to produce the necessary energy (ATP) tocarry out the activity. Walking, jogging, swimming, cycling, cross-country skiing, wateraerobics, rope skipping, and aerobics Anaerobic exercise: Exercise that does not requireoxygen to produce the necessary energy (ATP) to carry outthe activity. Burns primarily carbohydrates. Track and field (100, 200, 400 meters), swimming (100 meters),gymnastics routines, strength training Anaerobic activities will not increase cardiorespiratoryendurance significantly 9. Benefits of Aerobic Training Higher maximal oxygen uptake (VO2max) Maximum amount of oxygen the body is able touse per minute of physical activity, expressed inL/min or mL/kg/min; the best indicator of cardio-respiratory or aerobic fitness A high capacity to deliver and utilize oxygen indicates a more efficient cardiorespiratory system A low level of endurance indicates the heart has to work harder, less oxygen is delivered to the tissues, and the individual fatigues faster 10. Benefits of Aerobic Training Increase in oxygen-carrying capacity Decrease in resting heart rate (about 10-20bpm) and an increase in cardiac musclestrength Improves Cardiac output Amount of blood pumped by theheart in one minute Increases Stroke volume Amount of blood pumped by theheart in one beat Stroke Volume X Heart Rate = Cardiac Output Lower heart rate at given workloads(table 6.1) 11. Benefits of Aerobic Training Increase in number &size of mitochondria Increase in number offunctional capillaries Faster recovery time Lower BP and bloodlipids Increase in fat burningenzymes 12. Benefits of Aerobic Training 13. Physical Fitness Assessment Purpose of assessment Educate participants Motivate individuals Provide a starting point Evaluate improvements Monitor changes 14. Responders vs.Nonresponders A wide variation in physiological responses exists betweenindividuals who follow similar training programs Heredity plays a crucial role in how each person respondsand improves following an exercise program Principle of individuality: Studies have documented that some individuals readily experienceimprovements in fitness (responders), whereas others exhibit smallor no improvements at all (nonresponders ) following similarexercise training programs 15. Responders vs.Nonresponders As an average, VO2max increases between 15% and 20%following several months of aerobic training Individual responses can range from 0% (in a few selectedcases) to more than 50% improvement Nonresponders constitute less than 5% of exerciseparticipants Lack of cardiorespiratory endurance improvements amongnonresponders might be related to low levels of leg strength A lower body strength-training program has been shown tohelp nonresponders improve VO2max through aerobic exercise 16. Assessment of Cardiorespiratory Endurance Maximal oxygen utilized per minute ofphysical activity - VO2max Expression Liters per minute (L/min) Milliliters per kilogram per minute (mL/kg/min) Most often used to express VO2max because it takes into account ones body weight Factors influencing VO2max Genetics, training, gender, age, and bodycomposition 17. Assessment of Cardiorespiratory EnduranceComponents of Oxygen Uptake Heart rate Ranges from ~40 to 200 bpm (Maximal heart rate (MHR)) Stroke volume Ranges from 50mL in deconditioned to 200mL in highly trained athletes Increases significantly with endurance training Amount of oxygen removed from blood Arterial-venous oxygen difference (a-vO2 ) diff Venous O2 can range from 5mL/100cc at rest to 15mL/100cc (or more) during exercise 18. Assessment of Cardiorespiratory Endurance Using these three factors we can compute VO2 usingthe following equation: VO in L/min =2 (HR x SV x a-vO2diff) 100,000 Resting Oxygen Uptake Example SV = 79 mL HR = 76 bpm a-vO2diff = 5 mL/100 cc VO2 in L/min =(76 x 79 x 5) 100,000 = 0.3 L/min 19. Assessment of Cardiorespiratory Endurance We can use to same equation to figure MaximalOxygen Uptake (VO2max) Example SV = 120 mL HR = 190 bpm a-vO2diff = 15 mL/100 cc VO2max in L/min =(190 x 120 x 15) 100,000 = 3.42 L/min 20. Assessment ofCardiorespiratory Endurance Computing VO2 can also be determinedthrough gas analysis Computing VO2 throughthe previous methodsare impractical or toocostly for most fitnesssettings, so Submaximaltests are used 21. Test to Estimate VO2max 1.5-Mile Run Test Most frequently used test Maximal exercise test Based on time needed to run1.5 miles 22. Test to Estimate VO2max 1.0-Mile Walk Test Must walk at a pace to produce a heart rate of at least 120 bpm Use pulse at the carotid or radial artery Use predictionequation to estimateVO2max 23. Test to Estimate VO2max Step Test Submaximal workload Takes 3 minutes Not preferable for those withlower joint issues Astrand-Rhyming Test Bicycle ergometer Submaximal workloadMonitoring heart rate on the Most can complete carotid artery during theAstrand-Ryhming Test 24. Test to Estimate VO2max 12-Minute Swim Test Considered more of a maximal test Not practical test for everyonebecause of: Skill level ConditioningBody composition 25. Interpreting the Results of YourMaximal Oxygen Uptake After obtaining yourVO2max you candetermine yourcurrent level ofcardiorespiratoryfitness Cardiorespiratory Fitness Category According to Maximal Oxygen Uptake (VO2max) 26. Predicting Oxygen Uptake & Caloric Expenditure The human body burns about 5 calories for eachliter of oxygen consumed A person with a VO2max of 3.5 L/min exercising at60% of maximum uses 2.1 (3.5 x .60) liters ofoxygen per minute and burns 10.5 (2.1 x 5)calories per minute of physical activity If the activity lasts 30 minutes, 315 calories havebeen burned (10.5 x 30) Using this principle, one can determine the totalcaloric expenditure of a given session of physicalactivity 27. Predicting Oxygen Uptake &Caloric Expenditure For people concerned about weightmanagement, these computations arevaluable in determining energy expenditure One pound of fat represents 3,500 calories At 10.5 calories per minute, a person needsto exercise for a total of 333 minutes(3,500/10.5) to burn the equivalent of onepound of fat 28. Principles of CR ExercisePrescription A low percentage of the U.S. population iscommitted to exercise. More than half of those who begin to exercisedrop out during the first 36 months. Only about 19% of adults in the U.S. meetminimum recommendations of the ACSM forthe improvement and maintenance ofcardiorespiratory fitness 29. Principles of CR Exercise Prescription Readiness for Exercise (Lab 6C) The first step: "Am I ready to start an exercise program?" Scoring 12 or above in each category (mastery, attitude, health, andcommitment) in Lab 6C indicates that initiating and adhering to exercise areplausible. Next, decide positively to try. List the advantages, such as: It will make me feel better. I will lose weight. I will have more energy. It will lower my risk for chronic diseases (Figure 6.7). Compare to the disadvantages, such as: I dont want to take the time. Im too out of shape. Theres no good place to exercise. I dont have the willpower to do it. Identify the stage for cardiorespiratory endurance. Outline specific processes and techniques for change. 30. Guidelines for CR ExercisePrescription To develop the cardiorespiratory system, theheart muscle must be overloaded toincrease in size, strength, and efficiency Four FITT variables govern exerciseprescription: frequency, intensity, type(mode), and time (duration) Symptomatic individuals should undergo amedical exam prior starting or testing 31. Intensity of Exercise Health and cardiorespiratory fitness benefits occur when theperson is working between 40% & 85% of heart rate reserve(HRR) with appropriate frequency and duration Health benefits occur when training at 40% to 60% for alonger time Greater improvements in cardiorespiratory fitness occurthrough a vigorous-intensity program 60-85% as defined by ACSM Training intensity levels for unconditioned to healthy Low = 40% to 50% Moderate = 50% to 60% High = 60% to 85% 32. Recommended AerobicTraining Pattern Insert figure 6.6 from page 209 here 33. Intensity of Exercise Lab 6D Example: 20 yr old with RHR of 68 MHR:220 20 = 200 bpm HRR = 200 68 = 132 beats 40% TI = (132 x .40) + 68 =121 bpm50% TI = (132 x .50) + 68 = 134 bpm60% TI = (132 x .60) + 68 = 147 bpm85% TI = (132 x .85) + 68 = 180 bpm Low-intensity training zone: 121 to 134 bpm Moderate-intensity training zone: 134 to 147 bpm Vigorous (optimal) training zone: 147 to 180 bpm 34. Moderate- Vs. Vigorous- Intensity Exercise Vigorous-intensity programs yield higherimprovements in VO2max than do moderate-intensity programs. Higher levels of aerobic fitness are associatedwith lower cardiovascular mortality. Therefore, creating higher levels of CV fitnessthrough vigorous-intensity has a greater benefitthan just being more active (Moderate-intensity) 35. Relative Risk of CVD Basedon Weekly Volume of PA 36. Monitoring Exercise Heart Rate During the first few weeks of an exerciseprogram, you should monitor your exerciseheart rate regularly to make sure you aretraining in the proper zone. Wait until you are about 5 min+ into the aerobic phase of your exercise session before taking your first reading Count your pulse for 15 seconds and multiply by 4 to get the per minute pulse rate Consider personal fitness goals in determining TI Cross-check target zone with perceived exertion 37. Physical activity perceived exertion(H-PAPE) scale Rate of perceived exertion(RPE): A perception scale tomonitor or interpret the intensity ofaerobic exercise You have to associate your owninner perception of the task withthe phrases given on the scale Cross check your target zone withyour RPE during the first fewweeks of your program After several weeks, you shouldbe able to predict your exerciseheart rate just by your ownperceived exertion of the intensityof exercise 38. Mode of Exercise Aerobic activities It must be aerobic (involving the major muscle groups, rhythmic and continuous) to stimulate a cardiorespiratory response. Examples: walking, jogging, aerobic dance, swimming, water aerobics, cross-country skiing, rope skipping, cycling, racquetball, stair climbing, and stationary running or cycling. Choose using personal preferences and physicallimitations. Some activities first require skill development andbase conditioning before the TI can be maintained. 39. Duration of Exercise Approximately 2060 minutes per session is generallyrecommended. The less intense, the greater the required duration for anadequate training effect. Even though a continuous 30 minutes of exercise stimulatesgreater increases in aerobic power, three sessions of atleast10 minutes each provide significant cardiorespiratorybenefit.To prevent weight gain: accumulate 60 minutes of moderate- intensity physical activity most days of the week To prevent weight regain: 60 to 90 minutes of daily moderate- intensity activity. Exercise sessions should always be preceded by a 510 minutewarm-up and followed by a 10-minute cool-down period (Fig 6.6). 40. Frequency of Exercise Recommended = 3 to 5 days per week When exercising at 60%-85% of HRR, three 20-to 30-minute sessions on nonconsecutive days issufficient to improve or maintain VO2max Training at a lower intensity requires 30-60minutes more than three days a week Further VO2max improvements are minimal whentraining is conducted more than 5 days per week For health benefits, accumulate 30 minutes ofmoderate-intensity physical activity on most daysof the week 41. Summary Fig. 6-10 42. The Physical Activity Pyramid 43. Fitness Benefits of Aerobic Activities Beginners should start with low-intensity activities High-impact aerobics and rope skipping - risk for injuriesremains high even with conditioned participants These activities should be supplemental only and not the solemode of exercise Rhythmic and continuous activities that involve largeamounts of muscle mass are most effective in burningcalories High-intensity activities increase caloric expenditure Walking is a good exercise mode for weight management ifcarried out for 45-60 minutes five or six times per week 44. Fitness Benefits of AerobicActivities Physicians who work with cardiac patients use metabolicequivalents (METs) as an alternative method of prescribingexercise intensity METs are used to measure the intensity of physical activityand exercise in multiples of the resting metabolic rate One MET equals the rate of energy expenditure at rest or 3.5mL/kg/min The harder a person exercises, the higher the MET level 45. A Lifetime Commitment to Fitness Once you have determined your exerciseprescription, the difficult part begins: startingand sticking to a lifetime exercise program Lifelong dedication and perseverance arenecessary to reap and maintain good fitness The Tips to Enhance Exercise Compliancebox have been used successfully to helpchange behavior and adhere to a lifetimeexercise program. 46. A Lifetime Commitment to Fitness Staying with a physical fitness program longenough brings about positive physiological andpsychological changes. Four weeks of aerobic training are completely reversed in two consecutive weeks of physical inactivity. If you have been exercising regularly for months or years, two weeks of inactivity will not hurt you as much as it will someone who has exercised only a few weeks. 47. Real Life Stories 48. Real Life Stories CriticalThinking Questions 1. What changes did Yumiko make in her daily lifestyle to increase herlevel of physical activity? How much of an effort was required to do so? 2. How many steps per day do you routinely achieve? Is there adifference in the number of steps you achieve weekdays as compared toweekend days? 3. Are there any benefits to improving cardiorespiratory fitness, if one isstill overweight? 4. How can you use the rate of progression principle to achieve fitnessgoals? What are the advantages of not doing too much, too soon?