1. basics and background Flashcards

1
Q

Total daily energy expenditure (TDEE)

- 3 groups

A
  1. resting energy expenditure (REE)
    - 60-75%
    - basal metabolic rate / resting metabolic rate
  2. thermic effect of food (TEF)
    - 5-10%
    - possibly reduced in obesity (controversial)
  3. Physical activity
    ~ 15-30%
    - highly variable
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2
Q

difference between basic and resting metabolic rate

A

BMR
- strict controlled measurement conditions **

RMR
- ~10% greater than BMR

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3
Q

what stimulates the thermic effect of food (TEF)

A

protein and caffeine

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4
Q

factors that affect REE (resting energy expenditure)

A
genetics 
age
- young > old
sex
- men > women (muscle mass mostly)
body size
- height, body surface area
body composition 
- skeletal muscle biggest contribution (40% REE)
environmental temp
- cold, keep body warm
diet and exercise
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5
Q

measuring total energy expenditure

A

measure heat production

direct calorimetry
- persons heat production in sealed chamber

indirect calorimetry

  • measure changes in o2 consumption and/or co2
  • open circuit spirometry
  • “metabolic cart”
  • flow meters, gas analyzers
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6
Q

problems with indirect calorimetry

A

hyperventilation
- more co2 released
airtight?
mask comfort?

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7
Q

RER

- what can we determine from this

A

respiratory exchange rate

  • VCO2/VO2
  • determines the substrates being oxidized
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8
Q

VO2 use to calculate energy expenditure

A

thermal equivalent
~5 kcal per L O2

5 kcal X VO2 (L/min) X time

*nearly the same whether burning fat or oxygen

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9
Q

CO2 production (VCO2) assumptions when calculating energy expenditure

A

assumptions

  1. source of co2 production is mitochondrial
  2. steady state conditions are present
    - otherwise co2 not completely from fat or carb oxidation
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10
Q

what are non-steady state conditions

- co2 production that results

A

hyperventilation
- increases Vco2 production
recovery from intense exercise
- decrease Vco2

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11
Q

RER carb vs fat

A

pure carb = 1

pure fat = 0.7

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12
Q

what influences fuel utilization

A

at rest

  • fat use
  • low energy expenditure
  • no need to quickly replace ATP
  • enough time for lipolysis/beta oxidation
  • not fat exclusively (some cell/tissues need glucose)
  • 85% fat / 15% carb
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13
Q

what is VO2 max

A
  • maximum oxygen consumption and aerobic capacity
  • standardized progressive test
  • VO2 plateau
  • general indicator of aerobic fitness
  • L/min or ml/kg/min
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14
Q

VO2 max typical numbers

  • minimum
  • average 50th percentile
  • superior 90th percentile
  • well trained
  • highest elite
A

(men / women - ml/kg/min)

minimum - 35 / 32.5
average - 40-45 / 35-40
superior - 54+ / 47+
well trained - 60+ / 50+
highest elite - 90+ / 80+
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15
Q

oxygen supply vs oxygen demand

A

supply
- transport of O2 from lungs to mitochondria

demand
- rate at which mitochondria can reduce O2 in oxidative phosphorylation

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16
Q

major “limiter” to endurance performance

A

oxygen supply and delivery

17
Q

arterial oxygen saturation

  • %
  • is it limiting
A

how much oxygen each red blood cell is carrying

  • > 95%
  • not usually limiting
18
Q

high altitude training

A
body adapts to relative lack of o2
- increase mass of RBCs and hemoglobin
problem -> lower performance during
- live high train low
- tent, room, mask
19
Q

cardiac output measurement

- main limiting factor

A

stroke volume X heart rate

  • O2 supply and delivery
  • 70-85% of limitation
  • improved with endurance training

main limiting factor

  • stroke volume
  • HR is similar in trained/untrained
20
Q

O2 extraction

  • A-V diff
  • limiting?
A

A-V difference

  • 200 to 20 mL O2/ L in blood
  • little change with training
  • not likely limiting
21
Q

ways to increase o2 carrying capacity

- illegal

A

erythropoietin (EPO)
increase red blood cells
- can increase VO2 max by 10%

22
Q

peripheral limitations to VO2 max

A

McArdles disease

  • carbs
  • muscle phosphorylase deficiency, breakdown glycogen to glucose in muscle

CPTI (carnitine palmitoyl transferase 1) deficiency

  • fats
  • fatty acid oxidation disorder

mitochondria?

  • weak relationship b/w mitochondrial enzymes
  • usually not a limitation
  • can incr mitochondria 2-fold w training, but get 20-40% increase VO2 max (poor association)
23
Q

whats the advantage of mitochondrial content increasing so much with training (because it doesnt increase VO2 max)

  • result of better matching
  • meaning in practical term
A

better matching ATP provision and demand, especially at onset of exercise

  • better balance
  • decrease ATP, increase ADP, AMP and Pi
  • more reliance on fat as fuel