Lecture 5: Exercise Testing

Question 1

what is VO2 max

Answer 1

max O2 consumption a person can consume at max physical exertion

measures cardiopulmonary fitness and aerobic endurance

Question 2

what is a MET

Answer 2

metabolic equivalent of a task

used to describe intensity of exercise

1 MET = amount of energy used for 1 min quiet rest

directly correlated with VO2 max

exercise at a metabolic rate 5x the resting VO2 rate is equivalent to 5 mets

Question 3

1 MET is equal to what

Answer 3

3.5 mL O2 x kg x min

Question 4

what is the RPE scale

Answer 4

rate of perceived exertion

pt perceived intensity of exercise

used heavily in cardiopulmonary population

downside = subjective and dependent on pt reporting

Question 5

what is heart rate reserve

Answer 5

difference between Max HR and resting HR

Question 6

describe slow twitch mm fibers

Answer 6

aka oxidative

aerobic metabolism; used O2 + glucose to produce ATP

slow to fatigue

contacts slowly over long period of time

Question 7

describe fast twitch mm fibers

Answer 7

aka glycolytic

anaerobic metabolism; uses proteins + glucose to produce ATP with lactic acid byproduct

fatigues quickly

past contractions for short amount of time

Question 8

what are ventilatory thresholds

Answer 8

below certain intensities, aerobic metabolism is used to fuel the body

kidneys provide HCO3 to buffer the lactic acid produced by CO2 in anaerobic metabolism

Question 9

what happens at 1st and 2nd ventilatory thresholds

Answer 9

1st (VT1) = less aerobic metabolism, increasing anaerobic metabolism

2nd (VT2) = mostly anaerobic metabolism, virtually no aerobic metabolism

Question 10

how does the body switch between ventilatory thresholds

Answer 10

kidneys release HCO3 once blood lactate levels >2 at VT1

once kidneys can’t keep up with lactate being produced, blood pH signals respiratory center in brain to increase breathing rate to “blow off” excess CO2 between VT1 and VT2

if we have to breathe so fast to keep up with increasing CO2 levels, we cannot maintain simultaneous conversion at VT2

Question 11

impact of chronic exercise

Answer 11

reduce body mass

decrease risk of multiple chronic diseases

increased VO2 max; improved O2 extraction

lower HR and SBP at submit and max exercise intensities

increase number/size of mitochondria in mm

increased skeletal mm blood flow at max exercise intensity

improved QOL, concentration, mood, and self esteem

decreased anxiety, stress, and depression

Question 12

what is exercise testing

Answer 12

systematic and progressive increase in O2 demand; evaluate responses to increased demand

non-invasive and can be used in diagnosis and management of pts with CAD

Question 13

indications for a graded exercise test (GXT)

Answer 13

atypical chest pain

CAD evaluation

pre-participation exercise screening

functional assessment

assessment of arrhythmia, HTN, or other instability with exercise

Question 14

absolute contraindications to GXT

Answer 14

recent (<4-6 wks) MI

recent change in ECG

cardiac infection

unstable angina

decompensated HF

severe or symptomatic aortic stenosis

acute PE

2nd or 3rd degree AV heart block

unstable arrhythmia causing hemodynamic instability

any acute illness

Question 15

relative contraindications for GXT

Answer 15

ST depression on resting ECG

significant (>200/110 at rest) or uncontrolled HTN

L main CAD

valvular heart disease

compensated HF

cognitive impairment

uncontrolled metabolic disease

tachyarrhythmia or bradyarrhythmia

electrolyte abnormalities

MSK conditions

Question 16

things to remember/consider for exercise testing safety

Answer 16

signed informed consent

have appropriate equipment and supplies available to manage an emergency

knowledge of: when to exclude pts, when to terminate GXT, and skills needed to react to abnormal response

Question 17

when to use a low level GXT and examples

Answer 17

usually performed shortly after MI or CABG

helps predict subsequent course and identify high risk pts

examples: gait speed, 5x STS, 6MWT or 2MWT

Question 18

in a low level GXT what is the most valuable indicator of prognosis after MI

Answer 18

ST depression > 2.0 mm

early onset ST related to increased incidence of coronary events

Question 19

what does it indicate if a low level GXT induces ventricular arrhythmias

Answer 19

2.5x higher chance of sudden cardiac death

Question 20

limited exercise with low level GXT is highly correlated with what

Answer 20

Heart failure and increased mortality

Question 21

submit vs max GXT

Answer 21

submax = terminated at predetermined end point (usually % HR max); more feasible

max = terminated at max HR or when symptom limited; better sensitivity of testing for CVD/CAD

Question 22

Low level GXT protocol

Answer 22

vitals before, during, and after

edu to pt on protocol and equipment

warm up period

monitor HR at least 2x per stage

terminate at 85%. HR max

cool down period

continuous monitoring during recovery until pretest values reached

Question 23

describe Bruce treadmill test protocol

Answer 23

mostly in athletic population

can be max or submax

preferred method to predict functional capacity

speed = start at 1.7 mph, increase every 3 min

grade = start at 10%, increase 2% every 3 min

untrained subject usually tolerates <10 min to test

Question 24

Balke GXT protocol

Answer 24

large use in athletic population

stays at 3.3 mph

starts at 0% grade, increase to 2% after 1 min

after 2 min and each min after incline increases 1%

Question 25

YMCA step test

Answer 25

12 in step @ 24 steps/min x3 min

HR measured 1 min post test

compare max and 1 min recovery to age related norms

Question 26

12 min run test (cooper’s run test)

Answer 26

measure distance run or walked in 12 min

compare to norm data

Question 27

Astrand Rhyming Cycle Ergometer Test

Answer 27

estimates VO2 max

6 min cycling with pre determined wattage setting for 50 rpm

goal is to reach steady state HR between 125 and 170

Question 28

Wingate max exercise test

Answer 28

athletic and training situations

stationary ergonometer

after warm up:
- 30 sec resistance free max speed pedaling
- resistance added at predetermined level
- pedal as long as possible

Question 29

situations that constitute termination of GXT

Answer 29

angina
reaching 6 METs
poor perfusion (AMS, dizzy, cyanosis)
claudication
SBP decrease with work
BP > 250/115
1-2 mm ST depression
>9 VCs/min
any ventricular arrhythmia
subject requests stop

Question 30

absolute contraindications GXT

Answer 30

recent MI

recent change to ECG

cardiac infection

unstable angina

decompensated HF

severe/symptomatic aortic stenosis

acute PE

2nd or 3rd degree AV heart block

unstable arrhythmia/hemodynamic instability

any acute illness

Question 31

relato=ive contraindications for GXT

Answer 31

ST depression on resting ECG

significant or uncontrolled HTN

L main CAD

valvular heart disease

compensated HF

cognitive impairment

uncontrolled metabolic disease

tachyarrhythmia or Bradyarrhythmia

electrolyte abnormalities

MSK conditions

Question 32

what is pharmacologic stress testing

Answer 32

used if pt is unable to perform standard treadmill or cycle stress test

medication injected to induce physiological stress

same guidelines used while watching vital signs and response to exertion

most common in acute care or cardiologist