SUBMAXIMAL EXERCISE TESTING: ADVANTAGES AND WEAKNESS IN PERFORMANCE ASSESSMENT IN CARDIAC REHABILITATION

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1 SUBMAXIMAL EXERCISE TESTING: ADVANTAGES AND WEAKNESS IN PERFORMANCE ASSESSMENT IN CARDIAC REHABILITATION Dr Saari MohamadYatim M.D Rehabilitation Physician Hospital Serdang APCCRC, Hong Kong, 6-9 Nov 2014

2 5 leading diseases in Malaysia are: 1. Ischaemic heart 2. Mental illness, 3. Cerebrovascular disease/stroke 4. Road traffic injuries 5. Cancers

INSTITUTIONAL CARE AMBULATORY CARE CENTRES Hospital without Specialists in Districts

4 National Referral System, MOH, Malaysia Hospital Serdang National Referral Centres Regional Hospital/State Hospital Hospital with Specialists in Districts INSTITUTIONAL CARE AMBULATORY CARE CENTRES Hospital without Specialists in Districts Health Clinics 1 : 20,000 population Rural/Community Clinic 1:4,000 population PRIMARY HEALTH CARE

5 Maximal Exercise Testing Maximal exercise testing is considered the gold standard for assessing maximal aerobic capacity. The role of maximal testing limited in people whose performance may be due to pain or fatigue rather than exertion and in cases where maximal exercise testing is contraindicated.

6 VO 2 max VO 2 max is the most commonly used index to assess cardio respiratory endurance Definition -The largest amount of oxygen that an individual can utilize during strenuous exercise to complete exhaustion Has become the accepted measure of cardio respiratory endurance

7 VO 2 max Units liters/minute or ml/minute (absolute) ml/kg/min (relative to body weight) Range 15 (sedentary with disease) to 75 (young endurance runner) ml/kg/min Women about 10-20% lower than men

8 Methods of Determining VO 2 max Submaximally Maximally

9 GXT Graded Exercise Testing -GXT (incremental increases in workload) General Guidelines measure the subject s HR and BP and RPE at regular intervals (near the end of each stage [HR, BP, RPE] or every minute [HR]) if HR does not reach steady state during the stage extend stage 1 minute

10 Age vs. HR HR vs. Age HR (be a ts/m in) Age (years) HR - max

11 VO2 Peak When a maximal test is performed but the criteria for VO2max are not met, the maximal VO2 achieved is termed as VO2peak.

12 Several limitations to assessing maximal performance with a Vo2max test Unless an individual is able to attain a Vo2max without fatiguing first or being limited by musculoskeletal impairments or other problems, the results of the test are invalid. Higher levels of motivation are required by the individual

13 Maximal tests require additional monitoring equipment (eg, electrocardiograph machine) and trained staff and are labor intensive Compared with maximal exercise testing, submaximalexercise testing appears to have greater applicability Submaximaltests can be classified as either predictive tests or performance tests

14 Predictive Submaximal tests Modified Bruce Treadmill Test, Single-Stage SubmaximalTreadmill Walking Test, Astrandand RyhmingCycle ErgometerTest, 12-Minute Run Test, Canadian Aerobic Fitness Test (CAFT), 20-Meter Shuttle Test 1-Mile Track Walk Test (Rockport Fitness Test).

15 Performance submaximal tests Self-paced walking test Modified shuttle walking test Bag and carry test Timed up and go test 12-and 6-minute walk test

16 Self-paced walking test (SPWT) Developed for elderly and frail individual Consists of free walking at 3 speeds down an indoor corridor (ie, 250m) Exsresponses can be assessed: speed, time, stride frequency, stride length, HR, and predicted VO2max Cunningham DA, Rechnitzer PA, Pearce ME, Donner AP. Determinants of selfselected walking pace across ages 19 to 66. J Gerontol.1982;37:

17 Advantages Assess cardiopulmonary fitness as well as walking efficiency which are beneficial in daily activities Suitable for those requires mobility devices or when treadmill or cycle ergometer not indicated Suitable for monitoring older person s mobility Information from test can provide safety guideline (eg: for crossing an tersectionsafely requires a speed of 3.5 ft/s)

18 Weakness Does not provide a measure of endurance May not be sufficiently sensitive to test individuals higher levels of function It may be too difficult to complete the 3 selected walks with on 5 minutes rest

19 Modified shuttle walking test(mswt) Modified from 20-MST to provide standardized progressive test for symptom-limited maximum performance in chronic airway obstruction Individual walks up and down 10-m course at incremental speeds of 0.17 m/s each min dictated by a prerecorded audio signal on a cassette deck where as the original 20-MST required to run a 20- m distance at a starting speed of 8.5km/hr with increments of 0.5 km/hr each min Singh SJ, Morgan MDL, Scott S, et al. Development of a shuttle walking test of disability in patients with chronic airways obstruction.thorax. 1992;47:

20 Advantages Requires little equipments Easy to administer Audio signal standardizes the increment walking speed and motivates the individual Can be used to prescribe an appropriate walking speed for an exercise program by evaluating the individual s HR and RPE responses at various stages

21 Weakness Requires near-maximal effort by having the speeds continue to increase Familiarizing the individual with the pacing required for the test may require some time

22 Bag and Carry test (BCT) Used to assess a task that evaluates both endurance and muscle force Involves walking a circuit carrying a 0.9kg package for 7.5m, up and down a 4 step flight of stairs, and back 7.5m On completion of each circuit, 0.9kg is added to the package until the individual no longer complete the circuit It requires 10 min to complete Posner JD, McCully KK, Landsberg LA, et al. Physical determinants of independence in mature women. Arch Phys Med Rehabil. 1995;76:

23 Advantages Designed to integrate endurance, muscle force, and balance capability and is based on an everyday activity Easy to administer Can be used in research and clinical setting

24 Weakness No proper guidelines for administering this test in the literature No specifications regarding the height of steps, whether the individual is allowed to use a handrail for support or whether a practice trial is required

25 Timed Up & Go test (TUGT) Modified from the Get up & Go test Based on functional task of rising from a standard armchair, walking 3m, turning and returning to chair Changed the scoring system from an observer rating of 1 to 5 to a timed version Has been used as a test of mobility to assess change following an exercise program for elderly Podsiadlo D, Richardson S. The timed Up & Go : a test of basic functional mobility for frail elderly persons. J Am Geriatr Soc. 1991;39:

26 Advantages Easy to administer No training required Easy to perform in research and clinical setting Result provide info related to mobility The level of assistance required in mobility tasks can be determined

27 Weakness May not detect a change following an exercise program due to lack of sensitivity of the measure

28 12- and 6-minute walk tests 12MWT has been used primarily for COPD 1 6MWT has been used for end stage lung disease, chronic heart failure, COPD, children who are severely ill, chronic kidney failure and older adults 2 1. McGavin CR, Gupta SP, McHardy GJR. Twelve-minute walking test for assessing disability in chronic bronchitis. Br Med J. 1976;1: Butland RJ, Pang J, Gross ER, et al. Two-, six-, and 12-minute walking tests in respiratory disease. Br Med J. 1982;284:

29 Advantages Simple test Inexpensive Correspond to functional activities Can be used for healthy individual and patients with variety of diagnoses Allow the individual to set their own pace and stop if necessary Can detect a change following an exercise program

30 Weakness Variation in the rest periods between tests The scoring of test has also varied Lack of monitoring of physiological variables while the individual is completing the test Lack of specific performance criteria to ensure that a maximal effort is not performed

31 VO2 peak Prediction from 6MWT Cahalin et al. equation: VO2peak = [0.03 x 6MWD(m) ] E.g: 6MWD = 400m VO2peak = 0.03 x = ml/kg/min Est METs = 15.98/3.5 = 4.56 Cahalin, L. P. et al, The six-minute walk test predicts peak oxygen uptake and survival in patients with advanced heart failure. Chest 110: , 1996.

32 VO2 peak Prediction from 6MWT Sara Martin et al. equation: VO2peak = [ x 6MWD (m) ] e.g: 6MWD = 400m VO2peak = [ x ] = ml/kg/min Est. METs = /3.5 = 3.69 Sara Maldonado-Martín et al The Relationship of 6-min Walk to VO2peak and VT in Older Heart Failure Patients. Med Sci Sports Exerc. 2006;38(6):

33 Mean of 6 minutes walking distance 360 Initial assessment 431 First assessment Second assessment Third assessment

34 (CI 95% ) 100 Distance (m) (CI 95% ) 86 (CI 95% ) First assessment Second assessment Third assessment Difference in six minutes walking distance

36 Does performance test useful? Easy and inexpensive Not labor intensive Can be performed at bedside, clinic, low tech center or community center Can be performed by most of the patient Assess function

38 CRP Expansion

39 Reason for Expansion Increasing referral Logistic reason Physician willingness Motivated team members To increase patient enrollment

40 Start a small first, get it running And when it seems to be doing OK, See if you can dedicate more time Or more money to it Build it up gradually An ounce of prevention is better than a pound of cure. -Benjamin Franklin- (Jan 17,1706 April 17,1790)

41 THANK YOU

Submaximal Exercise Testing: Clinical Application and Interpretation. Performance, Prediction, Rehabilitation, Submaximal exercise test.

Perspective Submaximal Exercise Testing: Clinical Application and Interpretation Compared with maximal exercise testing, submaximal exercise testing appears to have greater applicability to physical therapists