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Flashcards in Exercise Physiology Deck (86)
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1
Q

Diffusive O2 transport

A

Passive movement of O2 down concentration gradient across tissue barriers

Based on metabolic rate, vascular resistance, tissue O2 amt

Depends on O2 tissue gradient and diffusion distance

2
Q

O2 demand

A

Amount of O2 required by cells for aerobic metabolism

3
Q

DO2

A

Volume of O2 delivered to systemic vascular bed per minute

CO x (arterial O2 content)

4
Q

VO2

A

Amount of O2 that diffuses from capillaries to mitochondria

5
Q

Oxygen Extraction Ratio

OER

A

Tissue oxygenation is adequate when tissues receive sufficient O2 to meet their metabolic needs

VO2/DO2

6
Q

CO (Q)

A

SV x HR

7
Q

SV affected by…

A

Pre-load (Left Ventricular End Diastolic Volume)

Myocardial distensibility (Diastolic mm length)

Myocardial contractility

After-load (Pressure that it has to push out against)

Can be measured via cardiac cath

8
Q

How we measure VO2

A

Arterial and venous line in patient

Measure difference to see what is truly being consumed

NOT directly measured by PTs

Indirect measurement - VO2 max test

9
Q

Open circuit spirometry

A

Occlude the nose and force breathing in and out from mouth

Look at differences and determine O2 use

Usually in cardiac rehab

10
Q

Calculating VO2

A

(VO2 entering) - (VO2 leaving)

Convert to mL/min

Divide by bw in kg

Final unit = mL O2/kg/min

11
Q

Basal Metabolic Rate

A

Rate of metabolism for an individual in a completely rested state

Work of breathing
Heart, renal, and brain fx
Thermal regulation (often looks at RMR)

12
Q

MET

A

Amount of O2 consumed while sitting at rest

1 MET = 3.5 mL O2/kg/min

13
Q

Energy cost of an activity

A

VO2/3.5

14
Q

Corrected METs

A

Concern about accuracy of MET level for RMR because it can OVERESTIMATE the RMR values for those that aren’t doing things that aren’t quite there

15
Q

VO2 max

A

Often use maximal and peak VO2 interchangeable

16
Q

Maximal

A

True max of what body could do if exercising all muscles at once

17
Q

Peak

A

When the body has “had enough”

18
Q

Peak in comparison to Max

A

The more mm groups working at once, the more closely Peak approximates Max

19
Q

LE vs UE

A

Max effort from LE gets a higher VO2 peak than if you were working all your mm in you UE

20
Q

How does exercise affect DO2 and VO2?

A

VO2 could increase 20-fold depending on exercise type

Blood flow increases to peripheral mm
Blood vessel dilation
Increases availability of O2 and extraction from blood

Increase in VO2 and DO2

21
Q

If DO2 declines…

A

VO2 will probably stay the same

Doesn’t necessarily mean you will have a decrease in your VO2

You might see a different in a critically ill patient because it might not meet metabolic demands

22
Q

O2 debt

A

Difference btwn O2 demand and O2 consumption

23
Q

PEOC

A

Post Exercise O2 Consumption

Needing more O2 to recover than body has available

24
Q

After STRENUOUS exercise…

A

Replenishment of…

ATP
Myoglobin with O2
Glycogen

Removal of…

Lactic acid

25
Q

Gravitational Stress

A

Ability for the CV system to accommodate fluid shifts is impaired with recumbence

Must adapt to gravity to restore fluid regulation

26
Q

Emotional stress

A

Autonomic nervous system responses

Sympathetic vs Parasympathetic

27
Q

Factors that perturb O2 transport

A

Gravitational stress
Emotional stress
Exercise stress

28
Q

Key when looking at CV and pulm fx…

A

Gravitational and exercise stress

They stimulate the reticular activating system, which, when dysfunctioning, inhibits O2 transport

29
Q

Upright positioning?

A

ALWAYS

Adjust hospital beds (chair mode)

30
Q

Sympathetic system

A

Fight or flight

31
Q

Exercise Stress

A

GREATEST PERTURBATION TO HOMEOSTASIS AND O2 TRANSPORT IN HUMANS

All steps of O2 transport affected

Increased…

CO, ventilation, HR, SV

Enhanced…

O2 extraction

32
Q

Left ventricle output

A

Increased by increase in HR, SV, and contractile pressure

which…

Increases systolic pressure and ejection of force

LV OUTPUT MUST EQUAL LV INPUT

33
Q

Diastolic filling time relation to HR

A

Indirect

34
Q

Diastole

A

Rapid and marked decrease in IV pressure

Creates a LV suction effect

35
Q

Systole

A

Increased systole leads to increased myocardial elastic recoil

36
Q

Myocyte relaxation

A

Acceleration of this happens because of…

Increase rate of Ca++ reuptake by sarcoplasmic reticulum

37
Q

With ischemia

A

Lose LV distensibility
LV wall stiffness
Increase diastolic pressure
Increases pulmonary congestion

38
Q

Can LV augment diastolic filling in response to exercise?

A

NO

39
Q

O2 diffusion at tissue level

A

Depends on QUANTITY and RATE of blood flow

Tissue and capillary O2 pressures
Capillary surface area
Capillary permeability
Diffusion distance

40
Q

What causes more rapid diffusion during exercise?

A

Capillary dilation…

Increases…

Surface area

Decreases…

Resistance to flow
Diffusion distance

41
Q

Immediate energy

A

When you move from resting state and begin to exercise

Use cellular ATP and Creatine Phosphate in mm fibers

Used in first 10 seconds or so of exercise

42
Q

Short-term energy

A

High intensity, near maximal efforts when immediate energy runs out

Anaerobic production of ATP via glycolysis

90 seconds or so

Sprinting short distances

43
Q

Long-term energy

A

Moderate intensity activities, sustained physical activity

Aerobic production of ATP

Need O2 supply to match demand

Long distance swimming

44
Q

Aerobic metabolism

A

Uses oxidative phosphorylation (Krebs)

Occurs in mitochondria

Requires O2

Primarily used in Type I SLOW TWITCH MM FIBERS

***Used primarily during low and mod intensity exercise

O2 should support demand needed for ATP

Uses carbs, fats, proteins

Yields 36 (skeletal) or 38 (cardiac) ATP per glucose

***Heart and CNS primarily use this

45
Q

Krebs cycle

A

Oxidative phosphorylation

Produces a lot of ATP, but SLOWER

46
Q

Glucose

A

Main fuel that’s used for high intensity exercise

47
Q

Anaerobic Metabolism

A

Does NOT require O2

Anaerobic phosphorylation

Uses ONLY carbs

Occurs in cytoplasm

By-product is lactic acid

Yields 2 (skeletal) or 6 (cardiac) ATP per glucose

***Used primarily during high intensity exercise

48
Q

Glycolysis

A

Doesn’t yield a lot of ATP, but occurs QUICKLY

49
Q

Anaerobic threshold

A

Around 55% of peak VO2… an individual cannot produce all ATP demanded aerobically and will need SOME anaerobic work to kick in

Intensity beyond which body increases reliance on anaerobic metabolism to meet body’s energy demands

Produces lactic acid

Why SOB with this? This leads to an inefficient O2 delivery situation; more acid build-up in body

50
Q

Lactate threshold

A

Lactic acid being produced faster that it is metabolized

51
Q

Anaerobic threshold

A

Results from increase in blood lactate

OBLA - onset of blood lactate accumulation

52
Q

Ventilatory threshold

A

Results from lactic acid broken down into lactate and H+

Leads to increase in CO2

Leads to increase in ventilation

SUDDEN, HEAVY VENTILATION

53
Q

Metabolic respiratory quotient RQ)

A

(CO2 produced) / (O2 consumed)

Used in calculations of BMR when estimated by CO2 production

aka RER

54
Q

Burning fat RQ

A

0.7

55
Q

Burning pure carbohydrate RQ

A

1.0

56
Q

Max RQ

A

1.15

If 1.08-1.1 shows subject gave good effort during an exercise test

57
Q

Physiologic Changes with Exercise

A

% increase of…

Frequency = 4x

Tidal volume = 8x

Minute ventilation = 32x

58
Q

Normal cardiac response to exercise

A

Increases in linear fashion with the work rate and O2 uptake during exercise

Increase in HR has expense of decreased diastole rather than systole

59
Q

Abnormal cardiac response to exercise

A

Lack of linear increase in HR with increased work or VO2

60
Q

Cardiac adaptation to training

A

Lower resting HR

HR with max exercise is the SAME of SLIGHTLY LOWER

61
Q

Normal SV response to exercise

A

Increases curvilinearly with work

Max around 50% aerobic capacity

Causes increased EF

62
Q

Abnormal SV response to exercise

A

Depressed SV or impaired increase in SV with work due to impaired ventricular compliance

63
Q

SV adaptation to training

A

SV and EF will increase

64
Q

How to measure SV

A

Pulse strength to get an idea ONLY

65
Q

Normal CO response to exercise

A

Increases linearly with increased work from 5 L/min to a max of 20 L/min

Due to increase in HR and SV

66
Q

Abnormal CO response to exercise

A

Failure to increase linearly with work rate

67
Q

CO Adaptation to training

A

Max level will increase

68
Q

Normal BP response to exercise

A

SBP increases linearly with CO during exercise

DBP should either remain constant or decrease slightly

69
Q

Abnormal BP response to exercise

A

Sudden sharp rise in SBP or lack of increase with exercise

DBP increase > 10 mmHg OR drops sharply > 20 mmHg

Should regulate after 3 min of standing

70
Q

BP adaptation to training

A

In healthy people SBP should remain the same

Only pt with HTN should get decrease in resting SBP with training

71
Q

Rate Pressure Product

A

HR * SBP

Very important to monitor during exercise with patient with heard disease

Strong correlation between RPP and myocardial O2 consumption (0.9)

72
Q

Normal RPP changes with exercise

A

RPP should increase with work rate

73
Q

Abnormal RPP response to exercise

A

Does NOT increase with work rate

Good marker of myocardial ischemia
***If no increase, NOT tolerating ex session well and at risk for ischemia

74
Q

RPP adaptation to training

A

Resting RPP may decrease over time…same at max effort

75
Q

Abnormal A-VO2 difference during ex

A

Impaired ability to extract O2

76
Q

A-VO2 adaptation to training

A

Improved ability to extract O2, so you can increase your exercise tolerance independent of central hemodynamic changes

77
Q

Normal VO2 max response to exercise

A

Can increase resting O2 consumption 10-fold

78
Q

Abnormal VO2 max response to exercise

A

Inability to increase O2 transport with increased energy demands

79
Q

VO2 max adaptations with training

A

Can increase resting O2 consumption 23-fold (endurance athlete)

80
Q

What reflects disability

A

16-18

Disabled

81
Q

Anaerobic threshold and exercise

A

Commonly associated with the onset of significant anaerobic contribution to exercise metabolism

Blood lactate is buffered during exercise to maintain a tolerable acid-base balance

82
Q

Anaerobic threshold response to training

A

Increased capacity to buffer and tolerate lactate

Training increases the anaerobic threshold

83
Q

Peripheral changes in response to training

A

Increased capillary density
Increased oxidative enzymes
Increased mitochondria

84
Q

Effects of bed rest and immobilization on exercise tolerance

A

Absence of gravitational and exercise stress

Resting tachycardia

Reduced cardiac output

Reduced VO2 max

Reduced blood volume

Reduced OE at tissue level

85
Q

Pulmonary complications of bed rest

A

Reduced lung volumes and capacities

Decreased thoracic volume

Restricted chest wall motion

Increased thoracic blood volume

Increased blood viscosity and decreased venous flow result in INCREASED risk of embolic event

86
Q

Convective O2 transport

A

Movement of O2 in air or blood

Determined by Hb concentration, O2 sat, and CO

Depends on active energy consuming processes