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16 Cards in this Set

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  • Back
What is a normal resting heart rate (RHR)?
60-80 bpm
How does HR change during exercise?
anticipatory response increases HR prior to exercise

during exercise, it increase directly in proportion to exercise intensity until it plateaus at the HRmax
What four factors determine stroke volume?
1. The vol of venous blood returned to heart (preload)

2. Ventricular distensibility (capacity to enlarge the ventricle for filling)

3. Ventricle contractility

4. Aortic or pulmonary artery pressure (against which the ventricles must contract)
Why does SV increase during exercise?
Frank-Starling mechanism (^vol blood enters the heart, heart stretches more, contracts harder, pushes more out)

^sympathetic stimulation=^catecholines circulating=^contractility

^vasodilation of blood vessels= decreased afterload (pressure to pump against)
What is the major determinant of cardiorespiratory endurance capacity?
Stroke Volume!
What happens to blood pressure during exercise?
Systolic increases as a result of increased cardiac output

Diastolic pressure stays the same or decreases slightly
What happens to mean arterial pressure during exercise?
MAP increases imediately and proportionately to exercise intensity
What is cardiovascular drift?
SV decreases and HR increases during prolonged exercise or exercise in the heat

*Decreased arterial BP
What happens to plasma volume during exercise?
It decreases due to sweating and through hydrostatic forces...this increases hemoconcentration
How does the (a-v)O2 change during acute exercise?
It increases because
What are three breathing irregularities?
Dypsnea (shortness of breath)
Hyperventilation
Valsalva maneuver
What is the ventilatory equilvalent for oxygen?
ratio between air expired (Ve) and oxygen consumed (VO2)

indicates breathing economy

usually remains relatively constant over various intensities of exercise
What is the ventilatory threshold?
point at which ventilation increases disproportionally to oxygen consumption

result of chemoreceptors picking up on increased CO2 levels (from lactate production)
Why is the respiratory system not a limitation to exercise performance?
• Respiratory muscles use ~11% of oxygen
during heavy exercise and up to15% of Co
• Pulmonary ventilation is usually not a limiting factor except in in some
highly trained athletes due to exercise-induced arterial
hypoxemia
• Respiratory muscles dont easily fatigue
• Airway resistance and gas diffusion is not usually a problem unless you have asthma or something
How does the respiratory system regulate acid-base balance?
-Chemical buffers (bicarbonate, proteins, phosphates) in the blood...bicarbonate bombines with H+ to reduce acidification
-Pulmonary ventilation (more oxygen= less lactate)
-Kidney function (removes waste stuff)
What is exercise induced arterial hypoxemia and who is affected?
40-50% of elite athletes

too large a demand on lung gas exchange=decline in PO2 and arterial oxygen saturation