Kin 3070 Exam 4 Flashcards
What are Cardiovascular responses to acute exercise?
Heart Rate, Stroke Volume, and Cardiac Output increase. Blood flow, and blood pressure also go up.
When you are just starting exercise what is responsible for early stages increases in cardiac output?
Musclemechanoreceptors
When you have been exercising for longer periods of time what is the primary thing that increases cardiac output?
Heart Rate
What happens to heart rate when you improve cardiovascular fitness?
Heart rate decreases, it can be as low as 28bmp
What is maximum heart rate?
The highest heart rate value one can achieve in an all-out effort to the point of exhaustion
Remains constant day to day and changes slightly from year to year…
Can be ESTIMATED: HRmax = 220 – age in years
What is the PRIMARY determinant of cardiorespiratory endurance capacity at MAXIMAL rates of work?
Stroke Volume
Stroke Volume increases during exercise but will eventually plateau, when does this happen?
SV will increase with increasing rates of work up to intensities of 40% to 60% of your VO2 max
Above 40-60% of VO2 max, SV generally plateaus
What are Cardiovascular Responses:
Factors That Increase Stroke Volume?
- Preload (Think: “Fill and Stretch”)
What it means: How much the heart fills with blood before it contracts.
During exercise: More blood returns to the heart → the heart stretches more.
Why it matters: A stretched heart muscle contracts harder — like pulling a rubber band further makes it snap back stronger.
Name for this: Frank-Starling mechanism.
✅ More fill = stronger squeeze = more blood pumped out.
⚡ 2. Contractility (Think: “Stronger Squeeze”)
What it means: How hard the heart squeezes.
During exercise: Your body releases adrenaline (epinephrine and norepinephrine).
Why it matters: These chemicals make your heart beat harder, not just faster.
Result: More blood is squeezed out with each beat = higher ejection fraction.
✅ Harder squeeze = more blood pushed out.
🩸 3. Afterload (Think: “Less Resistance”)
What it means: The resistance the heart has to pump against (mainly from the arteries).
During exercise: Blood vessels widen (vasodilation) to let more blood flow to the muscles.
Why it matters: Less resistance = easier for the heart to push blood out.
✅ Less resistance = easier pumping = more blood moved.
Among ELITE athletes, SV may continue to?
increase through maximal exercise intensity
At rest or any given work rate, how does body position influence HR? SV? Q? What are the specific amounts?
When you are supine HR is lower, SV is higher, and Q is about the same. When standing or sitting HR is higher, SV is lower, and Q is about the same.
Resting (supine) 55 HR 95 SV 5.2 Q
Resting (standing and sitting) 60 HR 70 SV 4.2 Q
Running 190 HR 130 SV 24.7 Q
Cycling 185 HR 120 SV 22.2 Q
Swimming 170HR 135 SV 22.9 Q
When we do long duration cardiovascular exercise what happens to MAP, Systolic BP and Diastolic BP?
SBP ↑ → heart working harder
DBP ↔ or ↓ → vessels in muscles widen
MAP ↑ slightly → not drastic, because body regulates it well
MAP may decrease over long durations of exercise, why?
During prolonged exercise, vasodilation + fluid loss can outpace the heart’s ability to maintain pressure, causing MAP to slowly decline — this is part of cardiovascular drift.
During RT what happens to MAP Systolic BP and Diastolic BP?
MAP increases, Systolic BP increases proportionally to the exercise intensity, diastolic BP increases due to muscle contraction.
MAP can get As high as 480/350 mmHg
Where are the three body regions that see significant increases in blood flow during exercise?
The muscles, the heart, the skin
What is cardiovascular drift and what happens to SV HR and MAP when this happens?
Cardiovascular drift happens when you exercise for a long time, especially in the heat. Even if you’re not going harder, your heart rate slowly goes up, and your stroke volume (amount of blood pumped per beat) goes down.
Why it happens:
You sweat, so your body loses water → less blood volume
Your blood moves to the skin to help cool you off
Because of this, the heart has less blood to pump each beat
So it beats faster to keep enough blood moving
SV decreases, HR increases, MAP decreases
What happens to plasma volume during exercise?
Pressure moves blood plasma to interstitial spaces
PV also lost through sweat, especially in hot
environments
10-15% reduction in PV with prolonged exercise
PV loss is proportional to intensity
Excessive PV loss can result in impaired performance
PV loss results in hemoconcentration - may be
beneficial!
What is ventilation and what is this at rest?
Ventilation (VE) is the product of tidal volume (TV) and
breathing frequency (f):
VE = TV X f
At Rest this is usually 6-10 L/min
Can rise to 100–160 L/min in healthy adults
In trained endurance athletes, it can reach >200 L/min
What is the point during intense exercise where ventilation increases disproportionately to oxygen consumption?
Ventilatory Threshold (TVENT) this is It’s the point during exercise when your breathing starts to increase faster than normal — not just because you’re working harder, but because your body is building up more lactic acid and needs to get rid of extra CO₂.
What triggers the increase in ventilation at the ventilatory threshold?
Increased CO₂ levels from fast glycolysis (via the bicarbonate buffering system)
At what % of VO₂max does the ventilatory threshold usually occur?
Between 55% to 70% of VO₂max
Why does the body rely more on glycolysis as exercise intensity increases?
Because oxygen delivery can’t meet demand, so the body switches to anaerobic energy systems (fast glycolysis
What two other thresholds occur at the same time as the ventilatory threshold (TVENT)?
Lactate Threshold (LT)
Onset of Blood Lactate Accumulation (OBLA)
What is Ventilatory Breakpoint AKA Ventilatory Threshold
This is the point during exercise when your breathing suddenly gets much faster, even though your effort is only going up gradually.
Is ventilation usually a limiting factor for performance at sea level?
No, it’s usually not a limiting factor.
