Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Unit 10 > Week 4: Exercise physiology Lab > Flashcards

Week 4: Exercise physiology Lab Flashcards

1
Q

What are the clinical applications of indirect calorimetry?

A

Assess functional capacity (VO2 max or symptom limited capacity.
Assess submaximal responses: metabolic efficiency
Diagnostic - e.g cause of dyspnea
Prognostic - identify risk of adverse effect/suitability for surgery
Evaluate impact on intervention - exercise programme
Exercise prescription
Nutritional - energy expenditure
Occupational assessment - deep sea divers
Metabolic cost of activity - economy and efficiency in terms of oxygen usage.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the metabolic threshold?

A

The point at which metabolic demands of exercise can no longer be met aerobically and an increase in anaerobic metabolism occurs. Reflected by an increase in blood lactate concentration and fatigue onset. Mirrored by changes in the ventilatory response.
Also referred to as the lactate threshold, ventilatory threshold or anaerobic threshold.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is indirect calorimetry measuring?

A

Quantifies gas exchange to estimate the energy expenditure of an individual.
Based on the respiration equation
Glucose + 6 O2 —-> 6CO2 + 6H2O and heat
Therefore measuring oxygen consumption can be used in a ratio to estimate heat production hence metabolic rate.
Assumes that pulmonary oxygen uptake is equal to oxygen uptake by tissues.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is metabolic rate?

A

The rate of energy production by the body.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does oxygen consumption relate to energy?

A

1L of oxygen consumption is equal to burning 5 kilocalories

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the limitations of indirect calorimetry?

A

Oxygen consumption is only proportional to energy production in aerobic respiration - this will be limited to a certain level of activity reached at varying intensities in different tissues.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does direct calorimetry work?

A

Chamber
Surrounded by a tank of a known volume of water
Give a known volume of oxygen into the tank and get the person to exercise
Measure the change in temperature of the water, use this to calculate the energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is closed circuit indirect calorimetry?

A

Breath from a known volume of oxygen, measure the change in volume of oxygen and energy expenditure is measured

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is open circuit indirect calorimetry?

A

Individual breaths from ambient air and expired air is analysed for carbon dioxide.
Use a ratio to calculate the oxygen consumption, then the energy expenditure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do you calculate the volume of oxygen consumed in calorimetry?

A

The changes in oxygen fractions
The changed in carbon dioxide fraction
The respiratory rate
Changes in baormetric pressure
Room temperautre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is total energy expenditure?

A

The amount of hear used by humans body for daily functioning.
Includes basal energy expenditure or resting metabolic rate
Diet-induced thermogenesis
Active energy expenditure (exercise)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What equations can estimate the resting metabolic rate?
What do they require?

A

Harris Benedict Equation - sex, age, height and weight
Miffline-St Jeor - sex, weight height and age

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the Harris-Benedict equation?

A

Male
66.5 +(13.8body mass in Kg) + (5.0height in cm)- 6.75* age in years

Female
655.1 + (9.6* body mass in Kg) + (1.84 * height in cm) - 4.6756 * age in years)

Calculates resting metabolic rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the Mifflin St-Jeor equation?

A

Calculates resting metabolic rate

Male = 5 + (10xweight kg) + (6.25xheight in cm) - (5 x age in years)

Women = (10xweight kg) + ( 6.25 x height cm) - (5* age in yrs) - 161

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How can we calcute energy expenditure by oxygen consumption?

A

VO2max (L.min-1) * (60*24) * 4.8kcal.min-1

Must be awake in supine, 10 hours after a meal, no physical activity within 8 hours, no strenuous exercise in last 24 hours, state of mental relaxation, ambient suitable temperature (Standard conditions)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why are different equation have different outcomes for basal metabolic rate?

A

Developed by testing on different populations
Indirect measurements have inherent measures e.g incorrect use of equipment/calibration
Based on different research results

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What makes up total energy expenditure?

A

resting metabolic rate - 60-70%
Diet induced thermogenesis - 6-10%
Physical activity - 20-30%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What factors influence total energy expenditure?

A

Age - decrease as age (loss of skeletal muscle)
Sex - higher in males (more lean)
Lean body mass
Hormones
Genetics
Temperature
Pregnancy etc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What clincal features increase resting metabolic rate?

A

Inflammation
Obesity
Physical agitation
Stress
Metabolic acidosis
Hyperventilation
Hyperthermia
Hyperthyroidism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What clinical features decrease resting metabolic rate?

A

Coma/deep sleep
Heavy sedation
Hypothermia
Gluconeogenesis
Metabolic alkalosis
Starvation
Sarcopenia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How does exercise energy expenditure quantified?

A

Sedentary = 1.2
Light = 1.375
Moderate = 1.55
Very active = 1.7525
Extra active = 1.9

These are factors that are multiplied by resting metabolic rate to include additional metabolic demand

22
Q

What is the respiratory exchange ratio?

A

The ratio between the VCO2 produced during cellular respiration and VO2 consumed
Estimates substrate utilisation under steady-state conditions
Indicates if the body is operating anaerobically or aerobically.
Divide VCO2 by VO2

23
Q

What does the value of respiratory exchange ratio mean?

A

0.7 to 1
0.7 is fat oxidation
1 is total carbohydrate oxidation
Lower ration tends to be aerobic.
Known as RER or RQ

24
Q

Are fats or carbohydrates preferred for oxidation by skeletal muscle at rest?

A

Fats
carbohydrates only used after a huge spike in blood glucose when insulin is released and allows increase cell utilisation.

25
Q

What is the average oxygen and energy expenditure at rest?

A

3.5ml of 02 per kg body weight per minute
or 1kcal per kg per hour.

26
Q

How to calcute the volume of oxygen consumed by the body?

A

Volume inspired - volume expired

27
Q

How to calculate the volume of carbon dioxide produced by the body?

A

Volume expired - volume inspired

28
Q

What are the proportions of gases in the ambient air we breath in?

A

O2 is 21%
CO2 is 0.03%
N2 is 79.4%

29
Q

What are the fraction of inspired oxygen and carbon dioxide?

A

Based on proportion of gases in ambient air
02 = 0.2093
CO2 = 0.0003

30
Q

What are the fraction of expired oxygen and expired carbon dioxide?

A

Proportion of gases in air expired and collected from patient (collected in a Douglas Bag)
Varies by person and exercise stage.
Typically collected for one minute

31
Q

What is pulmonary ventilation?

A

VE or minute ventilation
L.min-1

32
Q

What is VO2 and VCO2?

A

The volume of oxygen consumed per minute
The volume fo CO2 produced per minute

33
Q

What factors affect gas measurement?

A

Different temperatures - Charles law - directly proportional - higher vol in hot environment
Different pressures (atmospheric) - boyles law, increased pressure lower volume
These conditions must be standardised

34
Q

What are the conditions used when measuring gas volumes in the lab for calorimetry?

A

Standardised by using ATPS Atmospheric Temperature pressure and saturated
273 kelvin + room temper Barmoetric pressure 100%RH

Or by STPD standard temperature, pressure and dry
273 kelvin Standard pressure (760 mmHg) and 0%RH

35
Q

What valve is important in indirect calorimetry mouthpiece?

A

Hand Rudolph valve - ensure ambient air inspired and all expired air is measured not rebreathed.

36
Q

How often are air samples taken in indirect calorimetry? Why?

A

Every 3 minutes.
Ensure in a steady state (oxygen consumption is not changing at this level of exercise)

37
Q

What is the process of measuring gas volumes in indirect calorimetry?

A

Attach the sample line to the gas meter
Unclip the clip
Simultaneously start the timer
Observe changes in FeO2 and FeCO2
Record values when stable (around 40 seconds)
Re-attach clip at 60seconds
Attach inlet hosr to dry gas meter
Open valve and start the vaccume pump
Obserbive gas volume and Douglas bag deflating
record value when stable - add value to include amount of air typically left in the bag (0.2Litres)

38
Q

What is CPET purpose?

A

Cardiopulmonary exercise testing
Assess functional capacity during exercise, helps identify pathology.
Assess cardiopulmonary systes as rest and during exercise.
Should be used when standard clinical tests are inconclusive.
Provides information on metabolism.
Can predict pre and post-operative outcomes (due to physiological stress of operation affecting oxygen demand).

39
Q

What are the clincal considerations of CPET?

A
  1. Assess what limits functional exercise capacity and exercise intolerance
  2. Understand what may cause exercise-induced systems
  3. Cause of fatigue
  4. Pre-operative assessment - to determine if it will withstand physical demand of surgery, risk stratification of complication
  5. Evaluate disease severity and progression/regression - evaluate exercise and pharmacological intervention
  6. Used to plan an individualised exercise programme within the patient limitation
40
Q

What happens during a CPET test?

A

Test where physical stress (exercise normally on bicycle or treadmill) in progressively increased.
This puts stress on the cardiovascular, pulmonary and peripheral muscle systems that can then be measured.
Continued until a functional capacity end point is reached, or in the case of symptoms limited end point or opted end point (e.g earlier in older patients)

41
Q

What different causative factors can a CPET test differentiate between?

A

Cardiovascular
Pulmonary
Metabolic

42
Q

How safe are CPET tests?

A

Maximal exercise testing is safe in high risk patients in clear guidelines
Deaths 2 to 5 per 100,000 as exaggerates pathological events e.g increased risk of MI
Contraindications: MI, syncope, pulomary odema.

43
Q

What factors can reduce the risk of CPET?

A

Staff should be first aid trained, easy access to DEFIB
Staff should be trained on what symptoms to look out for on when to stop the test
Protocol for test (severity) should be based on patient (balance and health) - determine if bike or treadmill
Should match patient exercise level with previous data on patient functional capacity.
All protocols should start with a warm up.
If necessary submaximal tests should be used then extrapolated (six minute walk test)
Prescreening health check.

44
Q

What muscle groups are normally targeted in CPET?

A

Large muscle groups - often legs or arms
In athletes - suit to sport
Patients - best suited to symptoms
Safer to sit or stand

This is part of the protocol

45
Q

What is included in the protocol for exercise testing?

A

Muscle group targeted
Continous or discontinuous
Increment levels (too large fatigue prematurely)
Mode - cycle, treadmill, rowing
Maximal or suboptimal testing.
RAMP (progressive increasing) or steady state

46
Q

What are the advatanges/ disadvantages of using a treadmill in CPET?

A

Harder to collect blood gases and work rate measurements
More weight bearing
More leg muscle training
relies on patient having good balance
More space required in room (including a crash mat behind treadmill)
Older patients may not have used a treadmill and find it disorientating
Less likely to be used in UK

47
Q

What are the evaluations of using a cycle in a CPET?

A

Lower VO2 max
Eaiser to meausre work rate and collect blood gases
Is safer
More suitable for patient with poorer balance of capabilities.
Easier to accommodate in room/space.
However, less weight bearing and less leg muscle engagement.

Method of choice in the UK

48
Q

What is done in CPT?

A

3-minute resting (no activity) - ECG, arterial blood gases, Gas analysis - gives baseline physiological response
3 minutes unloaded cycling - basic warm up
Incremental workout test - RAMP protocol (increase every 30 seconds by smaller amount) or steady state. (Normally increase by 15% every 3 minutes until max reached)
Aim to get maximal exhaustion between 8 to 15 minutes.
Monitor for 10 minutes into recovery including 3 minutes low exercise

49
Q

What are the assumpations of graded exercise test?

A

Directly proportional increased between HR and oxygen consumption
(not true at high intensity)
Assumes exercise age predicted maximum heart rate equation.
Assumes equal mechanical efficiency throughout graded test.

50
Q

What protocols are preferred for a treadmill CPT?

A

Broose or modified Broose
Increase speed and gradient as test develops
Follows a step pattern, increased and steady then increased again.

51
Q

What protocols are used in submaximal cycle tests in CPT?

A

YMCA cycle protocol
Astrand cycle protocol

52
Q

What should be considered in all CPT tests?

A

Deconditioning - reduce functional capacity
Consider safety procedures needed in patients with co-morbidities.

Unit 10 (37 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions