Role of Cardiopulmonary Exercise Testing in Exercise Prescription Jonathan Myers, PhD VA Palo Alto Health Care System Stanford University There are no conflicts of interest to disclose
Role of Cardiopulmonary Exercise Testing in Exercise Prescription Clinical indications for CPX General principals of exercise prescription What are the advantages of CPX in exercise prescription? Other advantages of CPX in the context of exercise training General comment on physical activity and health
AHA/ACC Indications for CPX AHA/ACC Guidelines, 2002 ATS CPX Guidelines, 2003 ACSM Guidelines on Exercise Testing, 2010 ESC Working Group Statement, 2009 AHA Scientific Statement on CPX, 2010 When a precise cardiopulmonary response to a therapeutic intervention is necessary When a research question is being addressed When the etiology of exercise limitation or dyspnea is uncertain Evaluation of exercise capacity in patients with heart failure to assist in the estimation of prognosis and assess the need for transplantation When assisting in the development of an appropriate exercise prescription for cardiac rehabilitation
General principals of exercise prescription
The FITT Principal: Frequency, Intensity, Time, Type Frequency most days of the week Intensity 50-80% of maximum capacity (usually using heart rate reserve) Time minimum of 30 minutes - Moderate activity associated with numerous health benefits Type any aerobic activity - Resistance training should be incorporated into all fitness programs, including cardiac rehab
Why is the exercise prescription important? An individualized exercise guideline encourages a person to be more physically active
Effect of exercise Rx, clinician counseling on exercise Overweight adults who were advised by their physician to exercise were 5 times more likely to meet activity recommendations. Weidinger Fam Practice 2008 Patients receiving counseling 50% more likely to increase physical activity pattern. Kreuter et al Arch Fam Med 2000. Providing pedometer increased steps walked/day by >2,000, stairs climbed, days/week walking >30 min, frequency of exercise bouts. Stovitz et al J Am Board Fam Pract 2005 Numerous studies have shown that physicians who are physically active themselves are more likely to counsel patients on the benefits of exercise. Frank et al J Am Med Women s Assoc 2003; Abramson et al Clin J Sport Med 2000; Wee et al JAMA 1999 Three sessions of physician-delivered activity counseling by phone over 6 months resulted in greater physical activity. Green et al Am J Prev Med 2002 Physician-provided exercise Rx, with written materials, results in significant increase in physical activity over 8 months. Smith et al Br J Sports Med 2000 Activity counseling increased proportion of subjects meeting 30 min/5 days/week recommendation from 1 & 2% at baseline to 26 and 30% in men and women, respectively, at 2 years. ACT study, JAMA, 2001 Project PACE ( Provider-based assessment and Counseling for Exercise ) 3-5 min of counseling resulted in 4 times more participation in physical activity. Calfas et al. Prev Med 1996. Brief, one-time intervention by nurse and two-week follow-up phone call resulted in marked increases in energy expenditure over 6 weeks. Purath et al. Can J Nurs Res 2004. Two group counseling sessions increased physical activity in sedentary subjects by 70 min/week. Brekke et al J AM Diet Assoc 2003 Training physicians in motivational interviewing techniques resulted in 975 kcal/week greater energy expenditure among intervention subjects over 1-year. Elley et al. BMJ 2003.
Effect of exercise Rx, clinician counseling on exercise Overweight adults who were advised by their physician to exercise were 5 times more likely to meet activity recommendations. Weidinger Fam Practice 2008 Patients receiving counseling 50% more likely to increase physical activity pattern. Kreuter et al Arch Fam Med 2000. Providing pedometer increased steps walked/day by >2,000, stairs climbed, days/week walking >30 min, frequency of exercise bouts. Stovitz et al J Am Board Fam Pract 2005 Numerous studies have shown that physicians who are physically active themselves are more likely to counsel patients on the benefits of exercise. Frank et al J Am Med Women s Assoc 2003; Abramson et al Clin J Sport Med 2000; Wee et al JAMA 1999 Three sessions of physician-delivered activity counseling by phone over 6 months resulted in greater physical activity. Green et al Am J Prev Med 2002 Physician-provided exercise Rx, with written materials, results in significant increase in physical activity over 8 months. Smith et al Br J Sports Med 34:262-267 Activity counseling increased proportion of subjects meeting 30 min/5 days/week recommendation from 1 & 2% at baseline to 26 and 30% in men and women, respectively, at 2 years. ACT study, JAMA, 2001 Project PACE ( Provider-based assessment and Counseling for Exercise ) 3-5 min of counseling resulted in 4 times more participation in physical activity. Calfas et al. Prev Med 1996. Brief, one-time intervention by nurse and two-week follow-up phone call resulted in marked increases in energy expenditure over 6 weeks. Purath et al. Can J Nurs Res 2004. Two group counseling sessions increased physical activity in sedentary subjects by 70 min/week. Brekke et al J AM Diet Assoc 2003 Training physicians in motivational interviewing techniques resulted in 975 kcal/week greater energy expenditure among intervention subjects over 1-year. Elley et al. BMJ 2003.
Why is the exercise prescription important? An individualized exercise guideline encourages a person to be more physically active Helps ensure that activity is safe and appropriate for a given patient However, rigid guidelines not necessary for most stable patients or the public
What are the advantages of using CPX for exercise prescription?
What are the advantages of CPX in exercise prescription? More precise and reproducible measure of exercise capacity - Exercise prescription - Better measure of response to training More physiologic response to exercise More precise estimates of prognosis
What are the advantages of CPX in exercise prescription? Precision and Reproducibility
Measured METs (from measured VO 2 ) Measured vs. Estimated Peak Mets Among Treadmill Referrals* 20.0 15.0 10.0 6-7 METs 5.0 0.0 10 METs n = 1110 r = 0.55 p< 0.0001 0.0 5.0 10.0 15.0 20.0 25.0 Estimated METs (from work rate)
1105 ± 346 Exercise Time, sec 419 ± 140 1119 ± 376 462 ± 130 1123 ± 400 470 ± 131 VO 2, ml/min VO 2 and Exercise Time with Serial Testing 480 1035 470 460 Time, sec VO 2, L / min 450 1125 440 420 410 1105 400 390 1085 Test 1 Test 2 Test 3 Russell et al. Am Heart J 135:108;1998
503 ± 72 1559 ± 289 1553 ± 334 516 ± 85 526 ± 66 1557 ± 294 Time, sec 530 VO 2 and Exercise Time with Serial Testing 1600 525 520 Time, sec VO 2, L / min 1590 1580 515 1570 510 1560 505 1550 500 1540 495 1530 490 1520 Day 1 Day 2 Day 3 * Sullivan et. al., Chest 86:325
What are the advantages of CPX in exercise prescription? Precision and Reproducibility Exercise prescription and the ventilatory threshold
VCO 2 (L/min) Ventilatory Threshold (V-slope method) 4 3.5 3 2.5 2 1.5 1 0.5 0 CO 2 from Krebs cycle stimulates ventilation 0 0.5 1 1.5 2 2.5 3 3.5 VO 2 (L/min) CO 2 from Krebs cycle and lactate buffering further stimulates ventilation
Exercise prescription and the ventilatory threshold Ventilation increases exponentially beyond VT Difficult to exercise for long beyond VT Good upper limit of exercise Rx Good marker of the talk test Well established training response when Ex Rx is linked to the VT
Training at VT vs.% of Max VT = individualized at VT HR Reserve = standard training at HR Reserve Measure Group Change VO 2 max VT 20% HR reserve 10% VO 2 @VT VT 22% HR reserve 8% O 2 pulse VT 17% HR Reserve 9% Vallet 1997 Eur Respir J 10:114-122 (COPD patients)
What are the advantages of CPX in exercise prescription? Precision and Reproducibility Exercise prescription and the ventilatory threshold VO 2 reserve
VO 2 Reserve = (Peak VO 2 - Rest VO 2 ) x (% intensity desired) + Rest VO 2 Considered by some to be the gold standard ACSM Position Stand on Quantity and Quality of Exercise Eur Assoc Cardiovascular Prevention Rehabilitation Standards on CPX, 2009
Advantages of CPX in exercise prescription VO 2 Reserve: More closely reflects the range of metabolic rate than other methods - Not subject to the vicissitudes of heart rate: Variability Hyperthermia & Dehydration Fatigue Medications
What are the advantages of CPX in exercise prescription? Precision and Reproducibility Exercise prescription and the ventilatory threshold VO 2 reserve Documenting training response with CPX
Effects of Training on Exercise Capacity 16 12 14 54% 24% 10 12 10 8 6 11% 8 6 4 Time (Min) 4 2 2 0 Estimated METs Measured METs Exercise Time 0 Exercise Capacity Pre-Rehabilitation Post-Rehabilitation Milani, Lavie, Spiva. Am J Cardiol 75, 940-942
ml/kg/min Estimated METs Time (min) Exercise Training in AAA 10 16 9 8 7 6 14 12 10 5 8 4 3 2 1 6 4 2 0 Estimated METs 0 Exercise Time 30 26% 25 20 45% 15 10 5 8% 0 Pre-Exercise Peak VO2 Post-Exercise Myers et al., submitted, 2011
Exercise training improves the VE/VCO 2 slope in CHF: Coats et al. Circulation 85:2119, 1992 - VE/VCO 2 slope from 0.38 to 0.34 with 8 weeks of training Davey et al. Br Heart J 68:473, 1992 - VE/VCO 2 slope from 0.39 vs 0.35 with 8 weeks training Myers et al. Med Sci Sport Exerc 31:929, 1999 - VE/VCO 2 slope from 0.33 vs 0.27 with 8 weeks high intensity training Guazzi et al. J Appl Physiol 97:1866, 2004 - VE/VCO 2 slope from 0.33 vs 0.28 with 8 weeks training Anaya et al. Med Sci Sports Exerc 41:971, 2009-1.7 unit decrease in VE/VCO 2 slope in high risk women
Exercise training improves the OUES in CHF: Gademan et al. EJCVPR 15:140, 2008 - OUES increased 19% after 4 weeks of training Myers et al. JCRP, in press, 2011 - OUES increased 12% after 8 weeks of high intensity training Van Laetham et al. Eur J Heart Failure 9:625, 2009 - OUES increased 14% after 4 weeks of training Kemps et al Eur J Appl Physiol 108:469, 2010 - OUES increased 6% after 6 months of training
Exercise prescription and public health message regarding physical activity
Minimal recommendations for physical activity WHO, CDC, AHA, ACSM, US Surgeon General s Report, European Working Group* All individuals should attempt to accumulate 30 minutes of moderate activity on most, if not all, days of the week Additional health benefits can be gained through greater amounts of physical activity 30 minutes daily activity 20 to 40% reduction in cardiovascular and all-cause morbidity/mortality *Australia, Canada, Fiji, New Zealand, Germany, Singapore, the Philippines, Switzerland, which are generally based on the United States Surgeon General s recommendations for physical activity
Prevalence of Physical Activity in the European Union 6 Moderate Activity (Days/Week) 5 4 3 2 1 0 Austria Belgium Denmark Finland France Germany (West) Germany (East) Great Britain Greece Ireland Italy Luxembourg Netherlands Northern Ireland Portugal Spain Sweden Praventivmed 49:281-289
Exercise Prescription, Physical Activity and Health HR reserve Karvonen formula % VO 2 VO 2 reserve Training zone Perceived exertion Talk test Training range Ventilatory threshold Interval training Fat burning zone Polar HR, pedometer, accelerometer Find an activity that s enjoyable more likely to adhere Compulsive monitoring, narrow window for exercise Rx can be a barrier All clinicians should counsel patients on physical activity
Summary CPX permits a more precise and effective exercise prescription - Estimated METs less reliable CPX provides important insights into the training response - More precise - More physiologic response to training Physical activity counseling should be a part every clinical encounter