Graded Exercise Flashcards
What are the common measurements for all GXT procedures
Cardiac electrical conduction through 12-lead ECG’s, RPE, O2 consumption, blood pressure
How is blood pressure measured
BP= sBP/ dBP
Systolic blood pressure
Pressure in the arteries when the heart contracts
Diastolic blood pressure
Pressure in the arteries when the heart is filling between beats.
Pulse pressure
The difference between diastolic and systolic pressures (PP= sBP-dBP)
What is healthy blood pressure defines as
Less than 120/80 mmHg
Why does blood pressure change during age
Blood pressure rises steadily with age due to arterial stiffness and plaque buildup
Mean arterial pressure represents
The average pressure in the arteries during a cardiac cycle
Why is MAP important
It determines the rate of blood flow through the vasculature
MAP equation
MAP= dBP + 1/3PP
Why is map calculated like this?
The heart is in Diastole (relaxation) for 2/3rd of the cardiac cycle at rest
What happens to MAP measurement during exercise?
The MAP measurement loses accuracy because the heart is in systole (contraction) for a greater relative amount of time compared to at rest.
How is MAP determined centrally in exercise?
By cardiac output
How is MAP determined peripherally during exercise
By total peripheral resistance
What is the MAP equation for exercise
MAP= Cardiac output x total peripheral resistance
How is total peripheral resistance calculated?
It is the sum of all the blood flow in the vasculature
What influences blood pressure
Anything that changes cardiac output or total peripheral resistance; increasing either will increase BP
What is the main cause for blood pressure increasing during exercise?
There is a large increase in cardiac output due to elevated heart rate, left ventricular contractibility, and increased preload
How does stroke volume compensate to decrease after load (MAP)
Increase in stroke volume more than increasing BP will decreases map
What causes increases in after load during exercise?
Vasodi;atop of arterials supplying blood to active muscles
What is the net result of exercise on blood pressure?
Increase in systolic BP due to increased cardiac output while diastolic BP is relatively unchanged due to vasodilation
How are individuals categorized in the GXT assessment
Based on age, known disease, and risk factors
What levels need supervision or a medical exam prior to the GXT
Moderate risk individuals must undergo a medical exam prior; High risk individuals must be supervised by a physician during testing as well as undergo a medical exam prior
What happens prior to the GXT exam for all participants
Resting heart rate and blood pressure values are recorded.
When is the GXT stopped
It can be stoped at either a predetermined point or if the physician or participant decides to its necessary to terminate
How is the speed set for the GXT?
70-80% of the age predicted hr max
How long is each GXT stage?
2 minutes
How much does the treadmill increase per stage
2%
When is it safe to stop supervision of the subject
HR around 100 bpm
Why are GXT’s useful in determining cardiovascular health
It measures changes in BP and cardiac function so it identifies abnormalities during exercise. Many cardiovascular and physical abnormalities do not become apparent until the body is stressed
What changes in cardiac function occur during graded exercise?
Linear increase in Hr to max, linear increase in stroke volume until certain intensity
When does stroke volume plateau
At approximately 50 % in untrained individuals and at greater intensities in trained individual. SV may not even plateau in highly trained individuals
What trend does cardiac output follow during GXT?
Cardiac output increases greatly at first and then less as stroke volume plateaus
Electrocardiogram
Indication of the hearts ability to function normally under increased myocardial oxygen demand.
What changes the tempo of the QRS complex during exercise
Changes in heart rate caused by altered action potential duration, conduction velocity, and contractile velocity
What is the most common sign of myocardial ischemia (reduced blood flow) during a GXT
ST segment depression in an ECG
aerobic training effect on resting and submaximal HR
Aerobic training decreases resting and submaximal blood pressure and TPR
What changes at maximal heart rate
Diastolic pressure may change but systolic pressure and mean arterial pressure do not change at max
What is the range for elevated blood pressure
120-129/ <80
What is the range for hypertension stage 1
130-139/80-90
What is the range for stage 2 hypertension?
140+/90+
What is the range for hypertension crisis
180+/120+
What is used to indicate the heart’s ability to function normally under increased myocardial oxygen demand?
Electrocardiogram
What impacts blood pressure reading
Cuff to small or over clothing; back/ feet unsupported or legs crossed; Not resting 3-5 min prior; patient talking labored breathing; full bladder; pain; arm below or above heart level
