Cardiovascular Physiology
What is the normal resting blood pressure for a healthy adult, what do the first and last Korotkoff sounds indicate and why is one sound louder than the other?
Normal resting BP = less than 120/ less than 80
First sound (systolic) = As the cuff slowly deflates, blood forcefully squeezes through the compressed narrow artery, creating loud turbulent blood flow.
Second sound (diastolic) = As the cuff continues to deflate, the artery remains fully open and blood returns to smooth (laminar) flow.
What tissues are you measuring when you use the skinfold caliper?
subcutaneous fat
What is the reason steady-state should be reached before recording blood pressure during exercise?
When someone starts exercising, their heart rate, blood pressure, and ventilation all start changing quickly. Those early minutes aren’t stable, variables are fluctuating as the body is still adjusting to the new workload.
Would you accept a flow meter calibration with 2.5 L in, 2.505 L out, 9.2% change and why ?
If a participant cycles at 150 W with a cadence of 70 rpm, how much resistance (kp) are you adding on the basket?
150W = kp x 70rpm
150W/70rpm = 2.1kp
Basket = 1kp
Added = 1.1 kp
What is the definition of CO, what are the units for CO, what is the equation for calculating CO and define the variables in that equation.
Cardiac Output: Amount of blood pumped through the circulatory system in one minute
CO (L/min) = heart rate (bpm) x stroke volume (ml/beat)
Heart Rate (HR): The number of times your heart beats per minute (bpm)
Stroke Volume (SV): Amount of blood pumped out of the heart per beat (mL/beat)
If you have a 10 s rhythm strip from a patient, how can you calculate their heart rate quickly?
If you have a 6 s rhythm strip from a patient, how can you calculate their heart rate quickly?
If you have a 10sec rhythm strip from a patient, you can quickly calculate their heart rate by counting the number of QRS complexes and multiplying by 6.
EX: 10 QRS complexes x 6 = 60bpm
If you have a 6 sec rhythm strip from a patient, you can quickly calculate their heart rate by counting the number of QRS complexes and multiplying by 10.
EX: 6 QRS complexes x 10 = 60bpm
True or False: If a task requires a power output below critical power, it is possible to predict how long someone can sustain that task.
False: Below this threshold, energy systems can meet the demand without a progressive loss in performance, so the task is considered theoretically "sustainable"
What are MIP and MEP used to evaluate and what are the corresponding muscles that are being targeted for each?
If someone is coming off from a mechanical ventilator, which value would be affected?
Evaluate Inspiratory and Expiratory muscle strength.
MIP = Maximal Inspiratory Pressure (Diaphragm & External Intercostals)
MEP = Maximal Expiratory Pressure (Abdominal & Internal Intercostals)
MIP is the value most significantly affected. Because the ventilator breathes for the patient, the inspiratory muscles (specifically the diaphragm) undergo disuse atrophy and fatigue.
True or False: A sedentary 48-year-old male smoker can perform a 3-minute all-out test.
False
Sedentary +1
Smoker +1
Age +1 Male >35 years
What is the typical blood pressure response to dynamic exercise versus isometric exercise?
During dynamic exercise, systolic blood pressure increases while diastolic pressure remains relatively unchanged or may decrease slightly. During isometric exercise, both systolic and diastolic blood pressure increase substantially.
Explain how body fat % affects body density.
Body fat is less dense than muscle, so people with more body fat will have lower body density.
What is the definition of V̇E, what are the units for V̇E, what is the equation for calculating V̇E and define the variables in that equation.
Minute ventilation: the total volume of air that is inhaled and exhaled from the lungs in one minute.
V̇E (L/min) = Tidal Volume (breath depth) x Breathing Frequency (breath rate)
During flow meter calibration, a syringe is used to simulate lung volumes. Explain how the syringe represents human lungs and the specific volume required to achieve a passing calibration.
Moving the syringe mimics inhalation and exhalation (our lungs), generating airflow similar to real breathing.
By pushing and pulling the syringe at different speeds, you can simulate slow, normal, or rapid breaths.
A passing calibration is 3 L average stroke or less than 3% difference.
Where do dispose of the following:
Lancet, Lactate strip, Gloves, Gauze, Alcohol swabs
Identify where lactate threshold is:
1.6, 1.8, 2.2, 3.4, 6.9, 8.2, 10
Lancet -> sharps container
Lactate strip -> sharps container
Gloves -> dry biological wastes bin (if they don't have blood --> regular trash)
Gauze -> dry biological wastes bin (if they don't have blood --> regular trash)
Alcohol swabs -> regular trash
Lactate Threshold @ 3.4 (remember LT occurs closer to where the slope starts to increase rapidly. Right at the inflection point of the slope)
What happens to stroke volume and heart rate when a person goes from supine to standing up, and why?
When moving from supine to standing, gravity pulls blood down toward the lower extremities.
SV decreases because of venous pooling in the lower extremities, while HR increases to help maintain cardiac output and blood pressure.
Name the electrical deflection that corresponds to each of the following ECG waves: P wave, QRS complex, and T wave and what do they mean in relation to the heart cycle.
Describe what would be dysfunctional in the heart if the PR interval was unusually long?
atrial depolarization (P-wave): atrial contraction
ventricular depolarization (QRS complex): ventricular contraction
ventricular repolarization (T-wave): ventricular relaxation
If the PR interval was unusually long, then there would be a delay in the electrical conduction between the atria and the ventricles.
What is the significance of VD /VT ratio... do you want a low or high ratio and what causes that ratio to change?
A lower value of this ratio indicates more efficient ventilation because a smaller fraction of each breath is wasted in dead space.
A lower ratio = greater efficiency because an increase in tidal volume allows for a greater proportion of air to reach the alveoli for gas exchange.
During gas calibration, the following values are measured: room air contains approximately 20.95% O₂ and 0.04% CO₂, while a gas tank sample shows 16% O₂ and 4% CO₂. Explain what these values represent in terms of inspired and expired air, and why the differences exist.
Room air (20.95% O₂, 0.04% CO₂) → fraction of inspired air.
Gas tank sample (16% O₂, 4% CO₂) → represents fraction of expired air.
Reason for differences:
Oxygen is consumed by the body during metabolism, so O₂ decreases in expired air.
Carbon dioxide is produced by metabolism, so CO₂ increases in expired air.
What is residual volume and what is a good estimate value for RV?
What lung disease would cause you to have a higher RV and why?
Residual volume is the amount of gas left in your lungs after a maximal expiration. A good estimate is around 1 to 1.2 liters.
COPD: patients have trouble exhaling and air gets trapped in the lungs, so more air remains after exhalation = increasing RV.
Explain the following in relation to how our body controls blood flow.
Resistance in a single vessel: R ∝ η × (L / r4)
Flow: F ∝ (∆P × r4) / (η × L)
A small increase in vessel radius can dramatically increase blood flow and decrease resistance because radius is raised to the fourth power in both equations.
During exercise, the body dilates arterioles to widen their radius causing resistance to drop (inversely proportional to r4) and causes blood flow to increase to working muscles (flow is directly proportional to r4)
What are the three common sites used for the 3-site skinfold test in females and males, and what is the direction of the skinfold (vertical, diagonal, or horizontal) at each site?
For females: triceps (vertical), suprailiac (diagonal), and thigh (vertical).
For males: chest/pectoral (diagonal), abdomen (vertical), and thigh (vertical).
Give me an estimate resting values for the following: BP (mmHg), V̇O2 (mL/min/kg), V̇E (L/min), VT (L), BF (bpm), RER (V̇CO2/V̇O2), CO (L/min), SV (L), HR (bpm), RV (L), Lactate (mmol).
BP: <120/<80
V̇O2 (mL/min/kg): 2.5-3.5
V̇E (L/min): 6-10
VT (L): 0.5-1.0
BF (bpm): 10-15
RER (V̇CO2/V̇O2): 7.0-.8
CO (L/min): 5-6
SV (ml): 50-100
HR (bpm): 60-80
RV (L): .5-1.5
lactate (mmol) <2.0
Compare the change in VT and breathing frequency as a function of power output.
As power output increases during exercise, both tidal volume (Vt) and breathing frequency (Fb) increase to meet the greater metabolic demand for oxygen and the removal of carbon dioxide.
Initially, the increase in ventilation is driven primarily by an increase in VT (this allows for deeper, more efficient breaths).
As exercise intensity continues to rise and Vt approaches its physiological limit, further increases in ventilation are achieved mainly by an increase in breathing frequency.
What does RER stand for, whats the range, what does it represent, and can be greater than 1.0 and why?
Respiratory Exchange Ratio = V̇CO₂ / V̇O₂; reflects substrate utilization.
RER range .7-1.0
RER 1.0 carbohydrate metabolism
RER .7 fat metabolism
Yes, it can be greater than 1.0 due to the extra non-metabolic CO2 reproduced from the bicarboante buffering system.