Chapter 3 Flashcards
protein oxidation
-amino acids converted into glucose or various intermediates of oxidative metabolism
-protein burned in lab yields 5.65 kcal/g, but in body only 4.1 kcal/g [in body N, must be removed in urea cycle, which uses energy. Urea excreted in urine]
-to measure protein use for energy in body, we must know rate of urea formation
~requires urine collection over 12-24 hours
~since little protein used for energy, we usually ignore protein use in determining energy expenditure
Balancing Act For Fuels
HEAVIEST TO LIGHTEST
-ATP, PCr, CHO, Fat
MOST TO LEAST ENERGY SUPPLIED PER GRAM
-Fat, CHO, PCr, ATP
QUICKEST ATP TURNOVER RATE
-ATP, PCr, CHO, Fat
-balancing act between most efficient and lightest to store vs. what gives us ATP quickest
-review what fuel used what situations and how that applies to type of training you do.
EXAMPLE: sprinter vs. marathoner
Interaction Between Aerobic and Anaerobic ATP Production
-Energy for exercise comes from an interaction between aerobic and anaerobic pathways
effect of duration and intensity
- short-term, high-intensity activities
- long-term, low to moderate-intensity exercise
Resting Energy Requirements
AEROBIC
O2 CONSUMPTION (VO2)
-3.5 ml/kg/min
RESTING ENERGY EXPENDITURE
-1 kcal/min
relative measure of VO2: ml/kg/min
absolute measure of VO2: ml/min
Rest to Exercise Transition
ANAEROBIC AND AEROBIC
- In transition, VO2 increases rapidly and reaches steady-state in 1-5 min.
- Until VO2 reaches steady state, must use anaerobic systems
- ATP-PCr, then anaerobic glycol’s, then aerobic
- Once steady-state reached, mainly aerobic
O2 DEFICIT
- during time aerobic systems are ramping up, the difference between the steady-state VO2 and actual VO2 is O2 deficit
- exercise intensity
- training (aerobic training)
- lower O2 deficit, your body is used to it.
Recovery from Exercise
- MR remains elevated several min. post-ex
- Magnitude and duration of recovery period influenced by exercise intensity
- The higher the intensity of exercise
- EPOC (O2 debt)- VO2 above that needed at rest during initial minutes of recovery
- Extra O2 consumption after exercise to bring physiological variables back to resting level
CLASSICAL THEORY-reapy O2 deficit
- FAST (2-3 MIN)- rebuild ATP & PCr stores in blood and muscle
- SLOW (> 30 MIN)- remove lactate
Research EPOC Reasearch
OTHER “NON-ANAEROBIC” FACTORS ALSO INVOLVED
- Elevated Tb
- Elevated Hormone Levels
- Elevated HR
- Elevated Breathing Rate
INTENSITY
TRAINING [less EPOC]
Prolonged Exercise
- Aerobic
- Usually steady-state VO2 can be maintained during submax ex. of moderate duration
EXCEPTIONS
- hot/humid environment - VO2 “drifts” upward
- high relative work rate (>75% VO2 max)
- due to effects of increase Tb & E/NE
Incremental Exercise or GXTs
- TESTS USED TO DETERMINE
1. CV fitness (VO2 max)
2. Possible heart disease - Work rate increases every few (1-5) min. until subject can’t maintain desired power output
- Can be done on any type of ergometer
Aerobic Capacity, Maximal O2 Uptake or VO2 max
-POINT AT WHICH VO2 FILS TO INCREASE WITH DECREASE EXERCISE INTENSITY.
- Factors influencing
1. Cardiorespiratory ability to deliver O2 to muscle
2. Muscle’s ability to uptake and use O2 - Determined by genetics and aerobic training (equal influence on VO2 max)
- 15-20 % common w/aerobic training
- Best measure of cardiorespiratory endurance and aerobic fitness
- % VO2max-most commonly used measure of relative exercise intensity
Respiratory Exchange Ratio
- Other methods, such as direct calorimetry, exist to estimate energy expenditure, but indirect calorimetry by RER is most common method
- Ratio of CO2 expired to O2 inspired at lungs
- Indicated aerobic CHO vs. fat use (non-pro)
- assumes O2 and CO2 respired @ lungs = O2 and CO2 used/released by aerobic metabolism
- only valid when used at rest or during steady-state ex.
- RANGE:
- RESTING AVG:
