Prescription of Exercise for Health and Fitness

1. Prescription of Exercise for Health and Fitness Chapter 19

2. Learning Objectives • Find out how physically active American adults are in relation to the medical community’s recommendations for fitness. • Review the importance of receiving medical clearance before undertaking an exercise program

3. Learning Objectives • Learn methods of testing fitness levels via exercise tests • Review the components of a sound exercise program • Discover how to become more active and gain the benefits of regular exercise

4. National Problem • More than 60% of American adults are not regularly physically active. • 25% of all adults are not active at all. • Nearly 50% of American youths 12 to 21 years of age are not regularly vigorously active and physical activity declines during adolescence. • (these numbers are steadily growing worse!)

5. Kenneth Cooper, M.D. • Founder of the Cooper Institute and author of the book, Aerobics, in 1968, which is credited with starting the “fitness revolution” in the U.S.

6. Surgeon General: Physical Activity and Health • Published in 1996, recommendations included the following: • People of all ages, male and female, benefit from regular physical activity. • Thirty minutes of moderately intense exercise (e.g., 30 minutes of brisk walking) on most, if not all, days of the week can improve health. • Additional health benefits are gained with maintaining a regimen that is greater in volume and intensity.

7. Importance of Medical Clearance • Provides opportunity to check for early stages of disease • Helps identify those with risk factors • Helps develop an appropriate exercise prescription • Helps to motivate when knowing your current BP, body fat, and blood lipid values • Provides a baseline for changes in health

8. Who Must Receive Medical Clearance? • Men over 40 • Women over 50 • Anyone, any age, who has two or more risk factors for coronary artery disease (CAD) or symptoms or signs of cardiopulmonary disease

9. Components of Medical Clearance • CAD screening • Physical examination • Exercise ECG

10. • Pain or discomfort in the chest, neck, jaw, or arms (angina) • Shortness of breath at rest or with mild exertion (dyspnea) • Dizziness or syncope (fainting from reduced blood flow to the brain • Orthopnea (inability to breathe except in upright position) or paroxysmal (sudden reoccurrence) nocturnal dyspnea • Ankle edema • Palpitations or tachycardia • Intermittent claudication (limb pain during exercise usually from insufficient blood flow) • Known heart murmur • Unusual fatigue or dyspnea with usual activities Major Symptoms or Signs Indicative of Cardiopulmonary Disease

11. Exercise ECG’s • Obtained while exercising on a treadmill or cycle ergometer • Graded test by progressing rate of work from low up to maximal intensity • Monitored for arrhythmias and CAD indicators that occur during exercise but not rest • Consideration of sensitivity, specificity, and predictive value for specific subject

12. ECG Screening in the Young • The value of using an exercise ECG to screen for CAD in young, healthy individuals is questionable. • The sensitivity and predictive value of an abnormal test are generally low in this population, where there is a low prevalence of CAD.

13. ECG Screening in the Young • A medical examination might not be necessary if moderate exercise is started gradually in people without symptoms of cardiopulmonary disease.

14. Exercise test result Those with CAD Those without CAD Positive (abnormal) True positive (TP) False positive (FP) Negative False negative (FN) True negative (TN) SN = [TP/(TP + FN)] SP = [TN/(FP + TN)] PV = [TP/(TP + FP)] Note. CAD = coronary artery disease. An abnormal exercise test is defined as one in which the ST segment of the electrocardiogram is depressed, suggestive of a myocardial ischemia. Exercise ECG Test Sensitivity (SN), Specificity (SP), and the Predictive Value (PV), of an Abnormal Test Test is with respect to CAD as verified with an Arteriogram

15. Exercise ECG Test Sensitivity (SN), Specificity (SP), and the Predictive Value (PV), of an Abnormal Test Example: 100 subjects tested; 6 true positive; 10 false positive; 4 false negative; 80 true negative – SN = 6/(6 + 4) = 60%; SP = 80/(10 + 80) = 89%; PV = 6/(6 + 10) = 38% Test Sensitivity: SN = [TP/(TP + FN)]: the sensitivity is the proportion of “tested” positives with all positive cases in the population. A sensitivity of 100% means that the test recognizes all sick people as such. Test Specificity: SP = [TN/(FP + TN)]: the specificity of a test is the probability that if the person does not have the disease, the test will be negative. Predictive Value: PV = [TP/(TP + FP)]: the predictive value is the probability that in case of a positive test, that the patient really has the specified disease. As a practitioner, which test is more meaningful? Test is with respect to CAD as verified with an Arteriogram

16. Components of Exercise Prescription • Type- usually one or more CV endurance activities plus resistance training • Frequency- 3 to 5-d per wk (or more) • Duration- 20 to 30 mins at appropriate intensity is optimal (optimal is defined as the greatest benefit for time invested) • Intensity- generally 55% or 60% to 90% of HRmax or 40% or 50% to 85% of VO2max • Although, varies individually and health benefits can occur at lower intensities

17. Minimum Threshold for Benefits • A minimal threshold for frequency, duration, and intensity must be reached to gain aerobic benefits from an exercise. • This threshold varies individually. • For this reason, relatively unfit individuals should use preconditioning activities such as walking, jogging, aerobics, or cycling to gain fitness before switching to a sport or recreational activity.

18. Disease Risk Model (e.g. CAD, hypertension, Type II Diabetes)

19. Monitoring Exercise Intensity • Training heart rate (THR) • Can use linear relationship with VO2max • Can use the Karvonen method of maximal heart rate reserve • Can set a THR range • Metabolic equivalents (MET)- Oxygen requirements of an activity and its intensity • Ratings of perceived exertion (RPE)-Subjective rating of the difficulty of work

20. THR at 75% VO2max

21. Karvonen Method • Instead of using VO2, THR is determined as a percentage of the HRmax reserve. • Maximal heart rate reserve = HRmax − HRrest • To train at 60% of maximal heart rate reserve: • THR60% = HRrest + 0.60(HRmax − HRrest)

22. Heart Rate Range • Establishing a training heart rate range (THR) is a sensible way to monitor exercise intensity. • Start exercise with your HR in the low end of the range and progress to the upper end of the range over time.

23. Metabolic Equivalents (METS) 1.0 MET = resting metabolic rate (~3.5 ml O2/kg/min)

24. The Borg RPE Scale • Individual subjectively rates how hard he/she is working – when used correctly, it can be reasonably accurate

25. Relative intensity (%) . Rating of %VO2max or perceived Classification HRmax %HRmax reserve exertion of intensity < 35% < 30% < 9 Very light 35-59% 30-49% 10-11 Light 60-79% 50-74% 12-13 Moderate 80-89% 75-84% 14-16 Heavy ³ 90% ³ 85% > 16 Very heavy Adapted from Pollock and Wilmore (1990). Classification of Exercise Intensity Comparing Three Methods Based on 20 to 60 min of endurance activity

26. Use It or Lose It • One of the best ways to ensure health benefits from exercise is to continue a consistent exercise program throughout life. • Health benefits are rapidly lost once an exercise program is discontinued.

27. Exercise Program • 3-4 days per week • Warm-up and stretching • Endurance exercise • Cool-down and stretching • Alternate days • Flexibility training • Resistance training • Recreational activities

28. Warming Up and Cooling Down • Low intensity callisthenic-type exercises and stretching • Can decrease risk of injury and muscle soreness • Warm-up prepares the cardiorespiratory and muscle systems for more intense exercise. • Active cool-down prevents blood from pooling in the extremities.

29. Rehabilitation Through Exercise • Cardiopulmonary disease • Cancer • Obesity • Diabetes • Renal disease • Arthritis • Cystic fibrosis • Transplants