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Flashcards in 1. basics and background Deck (23):
1

Total daily energy expenditure (TDEE)
- 3 groups

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

2

difference between basic and resting metabolic rate

BMR
- strict controlled measurement conditions **

RMR
- ~10% greater than BMR

3

what stimulates the thermic effect of food (TEF)

protein and caffeine

4

factors that affect REE (resting energy expenditure)

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

5

measuring total energy expenditure

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

6

problems with indirect calorimetry

hyperventilation
- more co2 released
airtight?
mask comfort?

7

RER
- what can we determine from this

respiratory exchange rate
- VCO2/VO2
- determines the substrates being oxidized

8

VO2 use to calculate energy expenditure

thermal equivalent
~5 kcal per L O2

5 kcal X VO2 (L/min) X time

*nearly the same whether burning fat or oxygen

9

CO2 production (VCO2) assumptions when calculating energy expenditure

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

10

what are non-steady state conditions
- co2 production that results

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

11

RER carb vs fat

pure carb = 1
pure fat = 0.7

12

what influences fuel utilization

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

13

what is VO2 max

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

14

VO2 max typical numbers
- minimum
- average 50th percentile
- superior 90th percentile
- well trained
- highest elite

(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+

15

oxygen supply vs oxygen demand

supply
- transport of O2 from lungs to mitochondria

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

16

major "limiter" to endurance performance

oxygen supply and delivery

17

arterial oxygen saturation
- %
- is it limiting

how much oxygen each red blood cell is carrying
- >95%
- not usually limiting

18

high altitude training

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

cardiac output measurement
- main limiting factor

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

O2 extraction
- A-V diff
- limiting?

A-V difference
- 200 to 20 mL O2/ L in blood
- little change with training
- not likely limiting

21

ways to increase o2 carrying capacity
- illegal

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

22

peripheral limitations to VO2 max

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

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

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