weekend 2 lecture 6 Flashcards
Contraindications to exercise testing (from ACSM guidelines)
Unstable angina
Resting SBP >200mm Hg or resting DBP >110mm Hg
Orthostatic BP drop of >20mm Hg with symptoms
Critical AS
Acute Systemic Fever (above 102)
Uncontrolled atrial arrythmias
Uncontrolled ventricular arrythmias
Uncontrolled sinus tachycardia (>120bpm)
Uncompensated CHF
3rd degree AVB without a pacemaker
Active pericarditis or myocarditis
Recent embolism
Thrombophlebitis
Resting ST segment displacement (>2mm Hg)
Uncontrolled diabetes (resting blood glucose >400)
Other metabolic conditions (hyper/hypokalemia, hypovolemia)
Signs/Sx below which an upper limit for Exercise intensity should be set
Onset of angina or other symptoms of cardiovascular insufficiency
- Plateau or decrease in SBP, SBP>240, DBP>110
- Radionuclide evidence of left ventricular dysfunction or onset of moderate to severe wall motion abnormalities during exertion
- Increasing frequency of ventricular arrythmias
- Onset of other significant EKG changes (2nd or 3rd degree AVB, atrial fib, SVT, complex ventricular ectopy)
- Other signs/symptoms of exercise intolerance
What do I do if exercise testing cannot be performed to estimate a baseline exercise tolerance?
Duke Activity Status Index (DASI):
DASI = Sum of weights for yes replies
VO2peak (ml/Kg/min) = 0.43 x DASI + 9.6
Can You: Weight 1) Take care of yourself, that is, eat, dress, bathe, or use the toilet? 2.75 2) Walk indoors, such as around your house? 1.75 3) Walk a block or two on level ground? 2.75 4) Climb a flight of stairs or walk up a hill? 5.50 5) Run a short distance? 8.00 6) Do light work around the house like dusting or washing dishes? 2.70 7) Do moderate work around the house like vacuuming, sweeping floors? 3.50 8) Do heavy work around the house, like scrubbing floors or lifting items? 8.00 9) Do yard work like raking leaves, weeding, or pushing a power mower? 4.50 10) Have sexual relations? 5.25 11) Participate in moderate recreational activities like golf, bowling? 6.00 12) Participate in strenuous sports like swimming, singles tennis? 7.50
Approximate Energy Requirements in METs for Horizontal and Grade Walking
Dont think we really need to know this by heart
Speed MPH 1.7 2.0 2.5 3.0 3.4 2.75 %Grade 0% 2.3 2.5 2.9 3.3 3.6 3.9 2.5% 2.9 3.2 3.8 4.3 4.8 5.2 5.0% 3.5 3.9 4.6 5.4 5.9 6.5 7.5% 4.1 4.6 5.5 6.4 7.1 7.8 10.0% 4.6 5.3 6.3 7.4 8.3 9.1 12.5% 5.2 6.0 7.2 8.5 9.5 10.4 15% 5.8 6.6 8.1 9.5 10.6 11.7
Six Minute Walk Test (submax ETT)
-What is the reason for the test??
To prescribe exercise by estimating VO2
Regression equations estimating VO2:
Estimated VO2 = distance in feet x .012 - .735 Morone T etal. CHF patients study n=30
(r = .7)
Estimated VO2 max = distance in feet x 0.006 + 7.38
Cahalin et al. End stage
Lung dz. Study n =60
(r =.73) p<.0001 SEE = 2.68
Rate Pressure Product (RPP
HRR method
VO2 reserve
RP= HR x SBP
(% intensity) (HRmax – HRrest) + HRrest
(% intensity) (VO2max – VO2rest) + VO2rest
Normal vs Abnormal Exercise Responses
Heart Rate
Stroke Volume
Heart Rate
- Normal: increases in a linear fashion with the work rate and the oxygen uptake during dynamic exercise. The increase in the HR occurs primarily at the expense of diastole (filling time), rather than stytole.
- Abnormal: lack of a linear increase in HR with increase in work rate or increase in VO2.
- Adaptation to training: Lower resting heart rate; HR at maximal exercise is the same or slightly lower.
stroke volume- -Normal: Normal is between 60-100ml/beat, while SVmax is 100-120ml/beat. SV normally increases curvilinearly with workrate until it reaches near maximum at the level of approximately 50% of aerobic capacity. There is an increase in ejection fraction due to increased contractility from the catecholamine mediated sympathetic stimulation.
- Abnormal: Depressed SV, or impaired SV increase with exercise due to impaired compliance of the ventricle. The normal increase in SV may reach maximum earlier, due to ischemic changes in the myocardium which impair compliance and contractility.
- Adaptation to training: in a normal untrained person, the stroke volume and the ejection fraction will both increase with exercise training.
Cardiac Output- -Normal: increases linearly with increased work rate, from a value of approximately 5L/min to a maximum of 20L/min with upright exercise. At exercise intensities up to 50%, the increase in CO is due to increases in both HR and SV; thereafter, the increase is almost solely from the continued rise in HR.
- Abnormal: failure of the CO to increase linearly with workrate. - Adaptation to training: CO at maximal exercise will increase in a normal individual after undergoing exercise training.
Abnormal vs Normal Responses
Rate pressure product
Arteriovenous-Oxygen Difference
Maximum oxygen consumption and blood pressure
Anaerobic threshold
rate pressure product Normal: Should increase with increasing work rate.
Abnormal: Does not increase with increasing work rate. Good marker for myocardial ischemia, if you see this response clinically, it signifies to the clinician that the person is at risk for myocardial ischemia and is not tolerating the current exercise.
Adaptation to training: Resting RPP value may decrease over time with training.
Arteriovenous-Oxygen Difference
- Normal: reflects the ability of the skeletal muscle to extract oxygen. Conditioned persons have a greater ability to use oxygen at the cellular level than unconditioned persons.
- Abnormal: impaired ability of the skeletal muscle to extract oxygen.
- Adaptation to training: with training, the ability of the skeletal muscle to extract oxygen improves and thereby allows the person to increase their exercise tolerance independently of any change in central hemodynamics.
Maximum Oxygen Consumption
- Normal: Aerobic capacity is defined as the highest rate of oxygen transport and use that can be achieved at maximal physical exertion. A normal sedentary person can increase their resting oxygen consumption 10 fold, whereas an endurance athlete may increase their oxygen consumption 23 fold.
- Abnormal: Inability of the individual to increase their oxygen transport with increasing energy demands.
- Adaptation to training: VO2max should increase in response to training.
Blood Pressure
- Normal: normally SBP should increase linearly with CO during exercise. DBP should either remain constant or decrease slightly.
- Abnormal: sudden sharp rise in SBP or lack of increase in the SBP during exercise. DBP increases or drops sharply (> 20mm Hg)
- Adaptation to training: in normal untrained individuals without HTN, the SBP should remain the same after training.
Anaerobic Threshold
- Lactate threshold is commonly associated with the onset of significant anaerobic contribution to exercise metabolism. Blood lactate is buffered during exercise to maintain a tolerable acid-base balance.
- Adaptation to training: there is an increased capacity to buffer and to tolerate lactate. Training increases the anaerobic threshold.
ACSM Guidelines
Signs/Sx below which an upper limit for Exercise intensity should be set
Onset of angina or other symptoms of cardiovascular insufficiency
- Plateau or decrease in SBP, SBP>240, DBP>110
- Radionuclide evidence of left ventricular dysfunction or onset of moderate to severe wall motion abnormalities during exertion
- Increasing frequency of ventricular arrythmias
- Onset of other significant EKG changes (2nd or 3rd degree AVB, atrial fib, SVT, complex ventricular ectopy)
- Other signs/symptoms of exercise intolerance
Use Borg scale on those patients who
are on drugs which blunt HR response (Betablockers; ?Digoxin; ?Calcium channel blockers)
Factors to consider when designing an exercise program
primary and secondary medical diagnoses
- Meds - Physical conditioning at baseline - Activity preferences/personal goals or concerns
Goals for exercise training
- function
- quality of life
- possible central hemodynamic adaptations
- possible peripheral adaptations to exercise
Components of Exercise Prescription
think like Mode intenstiy, duration, What things particualry fall under intensity.
Frequency
-ACSM recommends 3-5 sessions per week
Intensity
Intensity prescription
-%VO2 Reserve Method:
Target VO2 = (exercise intensity%) (V02max – VO2 rest) + VO2rest
-%Heart Rate Reserve Method: Target HR = (HRmax – HRrest)(exercise intensity %) + HR rest -% HR ***note this method is not a good method for clinical populations due to the degree of error (+/- 30 bpm for 2 standard deviations) 220 – age = HR max Multiply estimated HRmax by % exercise intensity -Rating of Perceived Exertion -recommend 11-13 rating “light to somewhat hard” for initial exercise prescription -ACSM recommends 12-16 rating for physiologic adaptation to exercise Duration -Much controversy in this area Mode -ideally should focus on large muscle groups for aerobic training in the cardiac population.
