Steady-state HR: - If intensity ↑, so does _____ - Adjustment to new intensity takes __to__ min - The more intense, the longer to

- steady-state HR - 2-3 - achieve

Chapter 8 Flashcards by Zach Leupold

The Cardiovascular Responses

to Acute Exercise is:

Increases blood flow to working muscle

How well did you know this?

Not at all

Perfectly

The Cardiovascular Responses
to Acute Exercise is:
-Involves altered heart function, peripheral circulatory adaptations to:

Heart rate
Stroke volume
Cardiac output
Blood pressure
Blood flow
Blood

How well did you know this?

Not at all

Perfectly

The resting heart rate (rhr)
untrained rhr:
trained: rhr:

60-80

30-40

How well did you know this?

Not at all

Perfectly

Resting heart rate is Affected by

neural tone, temperature, altitude

How well did you know this?

Not at all

Perfectly

Anticipatory response:
HR ↑ above RHR just before start of exercise
-________ ↓
-_______&, ______ ↑

Vagal Tone

- Norepinephrine, epinephrine

How well did you know this?

Not at all

Perfectly

Heart Rate During Exercise is Directly _____ to exercise intensity

proportional

How well did you know this?

Not at all

Perfectly

Maximum HR (HRmax): highest HR achieved in ]

all-out effort to volitional fatigue

How well did you know this?

Not at all

Perfectly

Maximum Heart rate (hr max)

Highly reproducible
Declines slightly with age
Estimated HRmax = _____ – age in years
Better estimated HRmax = ___– (0.7 x age in years)

- 208

How well did you know this?

Not at all

Perfectly

Steady-state HR: point of plateau, :

optimal HR for meeting circulatory demands at a given submaximal intensity

How well did you know this?

Not at all

Perfectly

Steady-state HR:

If intensity ↑, so does _____
Adjustment to new intensity takes __to__ min
The more intense, the longer to

steady-state HR
2-3
achieve

How well did you know this?

Not at all

Perfectly

Steady-state HR basis for simple exercise tests that estimate

aerobic fitness and HRmax

How well did you know this?

Not at all

Perfectly

Stroke Volume (SV) ↑ With ↑ intensity up to __ to ___% V•O2max

Beyond this, SV plateaus to ____
Possible exception: elite endurance athletes

40-60

- exhaustion

How well did you know this?

Not at all

Perfectly

SV during maximal exercise ≈ double

standing SV

How well did you know this?

Not at all

Perfectly

SV during maximal exercise only slightly higher than

supine sv

How well did you know this?

Not at all

Perfectly

Supine EDV > ______

standing EDV

How well did you know this?

Not at all

Perfectly

Factors That Increase Stroke Volume:

↑ Preload:
↑ Contractility:
↓ Afterload:

How well did you know this?

Not at all

Perfectly

↑ Preload: end-diastolic ventricular stretch
– ↑ Volume of ______returned to heart
– ↑ Stretch (i.e., ↑ EDV) → ↑ contraction strength
Frank-Starling mechanism

venous blood

How well did you know this?

Not at all

Perfectly

↑ Contractility: inherent ventricle property
– _________ or ________→ ↑ contractility
Independent of EDV (↑ ejection fraction instead)

↑ Norepinephrine or epinephrine

How well did you know this?

Not at all

Perfectly

↑ Preload at lower intensities → ↑ SV

– ↑ Venous return → ↑ EDV → ↑ _____

-preload

How well did you know this?

Not at all

Perfectly

Increase in HR → ↓ filling time → slight ↓ in EDV → ↓ _____

Stroke Volume SV

How well did you know this?

Not at all

Perfectly

↑ ________ at higher intensities → ↑ SV

Contractility

How well did you know this?

Not at all

Perfectly

↓ Afterload via vasodilation → ↑ _______

How well did you know this?

Not at all

Perfectly

HR x SV

How well did you know this?

Not at all

Perfectly

↑ With ↑ intensity, plateaus near

V•O2max

How well did you know this?

Not at all

Perfectly

Normal values of cardiac output: Resting Q• ~__ L/min Untrained Q•max ~__ L/min Trained Q•max __ L/min

- 5 - 20 - 40

Q•max a function of

body size and aerobic fitness

Calculation of tissue O2 consumption depends on blood flow, O2 extraction V•O2 =

V•O2 = Q• x (a-v- )O2 difference V•O2 = HR x SV x (a-v- )O2 difference

During endurance exercise, mean arterial pressure (MAP) increases - Systolic BP ↑ proportional to _____ - Diastolic BP slight ↓ or slight ↑ (at max exercise)

-exercise intensity

MAP = Q• x ______

total peripheral resistance (TPR)

MAP = Q• x total peripheral resistance (TPR) -Increased MAP from increased Q• helps to increase blood flow -During prolonged steady-state endurance exercise, MAP due to TPR ↓ slightly -Vasoconstriction blunted by ______

-sympatholysis

Rate-pressure product =

HR x SBP

Resistance exercise → _________ Up to 480/350 mmHg More common when using Valsalva maneuver

periodic large increases in MAP

↑ Cardiac output → ↑ ______

available blood flow

Blood Flow Redistribution Must redirect ↑ blood flow to

areas with greatest metabolic need (exercising muscle)

Sympathetic vasoconstriction shunts blood away from ______ - Splanchnic circulation (liver, -pancreas, GI) - Kidneys

less-active regions

Local vasodilation permits additional blood flow in exercising muscle - Local VD triggered by metabolic, endothelial products - Sympathetic vasoconstriction in muscle offset by _______ - Local VD > neural VC

-sympatholysis

As temperature rises, skin VD also occurs – ↓ Sympathetic VC, ↑______ Permits heat loss through skin

sympathetic VD

Cardiovascular Drift is Associated with

↑ core temperature and dehydration

SV drifts ↓ Skin blood flow ___ Plasma volume ↓ (sweating) Venous return/preload ↓

↑

during cardiovascular drift: | HR drifts _ to compensate (Q• maintained)

↑

(a-v- )O2 difference (mL O2 / 100 mL blood) - Arterial O2 content – mixed venous O2 content - Resting: ~___ mL O2 / 100 mL blood - Max exercise: ~___ to __ mL O2/100 mL blood

- 6 | - 16-17

Mixed venous O2 ≥___ mL O2 / 100 mL blood - Venous O2 from active muscle ____ - Venous O2 from inactive tissue > active muscle - Increases mixed ______

4 ~0 mL venous O2 content

↓ Plasma volume → hemoconcentration Fluid percent of blood ____, cell percent of blood ____ Hematocrit increases up to __% or beyond

decrease, increase | 50

Net effects of hemoconcentration

- Red blood cell concentration ↑ - Hemoglobin concentration ↑ - O2-carrying capacity ↑

Cardiovascular responses to exercise complex, fast, and finely tuned - First priority: maintenance of ________ - ---Blood flow can be maintained only as long as BP remains _____ - ---Prioritized before other needs (exercise, thermoregulatory, etc.)

- blood pressure | - Stable

Immediate ↑ in ventilation - Begins before ____ - Anticipatory response from ______

- muscle contractions | - central command

Gradual second phase of ↑ in ventilation -Driven by _______ – ↑ CO2, H+ sensed by ______

- chemical changes in arterial blood | - chemoreceptors

Ventilation increase proportional to ______ At low-exercise intensity, only _______↑ At high-exercise intensity, _____ also ↑

- metabolic needs of muscle - Tidal Volume - Rate

Ventilation recovery after exercise delayed - Recovery takes several ______ - May be regulated by _______

- minutes | - blood pH, PCO2, temperature

Dyspnea (shortness of breath) - Common with poor aerobic fitness - Caused by inability to adjust to high_______ - Also, fatigue in ______

- blood PCO2, H+ | - respiratory muscles

Hyperventilation (excessive ventilation) -Anticipation or anxiety about exercise – ↑ PCO2 gradient between alveoli (___ mmHg), blood (__ mmHg) – ↓ Blood PCO2 → ↑ blood pH → ↓ drive to breathe

-40 & 15

Valsalva maneuver: potentially dangerous but accompanies certain types of exercise - Closed ____ – ↑ ______ P (bearing down) – ↑ _______P (contracting breathing muscles)

- glottis - Intra-abdominal - Intrathoracic

Valsalva maneuver: | High pressures collapse great veins → ↓

venous return → ↓ Q• → ↓ arterial blood pressure

Ventilation matches:

metabolic rate

Ventilatory equivalent for O2 - V•E/V•O2 (_____________) - Index for control of breathing properly matched to _________

- (L air breathed / L O2 consumed / min) | - to body’s demand for oxygen

Ventilatory threshold is the: -Associated with lactate threshold and ↑ PCO2

Point where L air breathed > L O2 consumed (50% to 75% VO2 max)

Ventilation normally not limiting factor - Respiratory muscles account for __% of V•O2, __% of Q• during heavy exercise - Respiratory muscles very______

- 10 - 15 - fatigue resistant

Airway resistance and gas diffusion normally not

limiting factors in normal, healthy individuals exercising at sea level

Restrictive or obstructive respiratory disorders can

limit performance in patients

Exercise-induced arterial hypoxemia (EIAH) by ________ (40%-50% of elite endurance athletes) -High Q•, high rate of blood flow through lungs, not sufficient time for saturation with oxygen

ventilation-perfusion mismatch

Metabolic processes produce H+ → ↓ ___

H+ + buffer →

H-buffer

At rest, body slightly alkaline 7.1 to 7.4 Higher pH =

alkalosis

During exercise, body slightly acidic 6.6 to 6.9 Lower pH =

acidosis

Physiological mechanisms to control pH -Chemical buffers: _______, ____, ______, _______ – ↑ Ventilation helps H+ bind to _______ -Kidneys remove H+ from ____, excrete H+

- bicarbonate, phosphates, proteins, hemoglobin - bicarbonate - buffers

Active recovery facilitates pH recovery Passive recovery: __ to __ min Active recovery: __ to __ min

- 60-120 | - 30-60

Chapter 8 Flashcards

(66 cards)