Energy Sources (Part 3) Flashcards
How is the respiratory quotient (RQ) calculated?
RQ = volume of carbon dioxide / volume of oxygen
The RQ for carbohydrates = _
The RQ for fat = _
The RQ for protein = _
1
- 7
- 8
What is the average respiratory quotient during rest?
0.83
What happens to the RQ as intensity increases? Explain why…
It becomes closer to 1, because during high intensity activities more carbs are being used and their RQ = 1.0
1 kg of weight lifted 1 meter requires how many mL of oxygen?
1.8
For every 1 liter of oxygen consumed how many kcal are produced? How long does this process take?
5 kcal
5 minutes
With every MET increase systolic BP raises - mm Hg
5-10
The amount of energy per gram of substrate is highest in ____. However, per liter of oxygen used in aerobic metabolism, more energy is produced when metabolizing ____.
fat
carbs
What are 3 factors that result in the gradual switch from a predominant reliance on triglyceride metabolism at rest to an increasing dependence upon carbohydrates as energy demands increase during high-intensity exercise?
- Carbohydrate metabolism produces more energy per liter of oxygen
- More fast-twitch muscle fibers are recruited
- Hormonal changes, especially an increase in epinephrine
At what exercise intensity is the rate of fat metabolism maximized?
approximately 65-75% of maximal HR
What are the 2 factors that affect the availability of triglyceride in the form of free fatty acids for use in aerobic metabolism?
- increase in the hormones that increase the activity of lipases
- ingesting high-carb meal or drink
Ingesting high-carb meals and endurance training help to increase what?
liver and glycogen stores
What happens when intramuscular and liver glycogen stores are depleted during long-duration, low-intensity activity?
fat is metabolized
Define lactate threshold
The exercise intensity at which blood lactic acid begins to accumulate above the resting concentration
What is onset of blood lactate accumulation (OBLA)?
the exercise intensity at which a specific blood lactic acid concentration occurs
In untrained individuals, lactate threshold occurs at approximately __-__% of maximal oxygen consumption
50-60
In endurance trained individuals, lactate threshold occurs at approximately __-__% of maximal oxygen consumption
65-80
Lactic acid production exceeds removal during _____ metabolism
anaerobic
As lactate threshold increases, endurance performance ______.
increases
A higher lactate threshold allows for what?
performance of higher exercise intensity without an increase in blood lactic acid concentration
How does an increase in mitochondrial size and/or number result in an increase in an increase in aerobic ATP production
Because aerobic enzymes are located in the mitochondria and an increased enzymatic activity in the Krebs cycle and ETC would result in increased ATP production
What are the 2 substrate adaptations that improve endurance?
- increase in substrate availability
- increase substrate metabolism
How long does it take for lactate threshold adaptations to occur?
3 weeks
What are the 3 things that increase the ability to perform aerobic metabolism?
- increases in enzyme concentrations
- increases in mitochondrial density and volume
- increases in blood supply
Define oxygen debt
The period during which the level of oxygen consumption is below that is necessary to supply all the ATP required of any exercise
Define steady-state oxygen consumption
The condition in which all energy needed is provided by aerobic metabolism
During steady-state oxygen need _____ work
equals
Is there an increase in lactic acid levels during steady-state?
No
Define oxygen deficit
The difference between the amount of oxygen actually consumed during exercise and that which would be consumed if energy demands could be met solely through aerobic metabolism
Indirectly, what does oxygen deficit refer to?
the anaerobic energy used to perform a particular workload
What are the 2 phases of oxygen debt?
- rapid phase
- slow phase
Describe the rapid phase of oxygen debt
It typically lasts approximately 2-3 minutes and the majority of intramuscular PC is resynthesized
__% of the lactic acid produced during exercise is aerobically metabolized, __% is used to synthesize glucose, and __% is used to synthesize gluconeogenic amino acids
70
20
10
Does oxygen debt = oxygen deficit?
No
Define excess postoxygen consumption
The amount of oxygen taken in above resting values after an exercise bout
What are the 2 ways to recover following exercise?
Active or passive recovery
Which form of recovery decreases blood lactic acid concentrations significantly faster?
active
What are the 2 ways to measure energy production?
- direct calorimetry
- indirect calorimetry
What does direct calorimetry use to determine metabolic rate?
heat production measurements
What does indirect calorimetry use to determine metabolic rate?
oxygen utilized, CO2 produced, and the ratio between the 2
Define basal metabolic rate
The metabolic rate determined in the supine position, 12 to 18 hours after a meal, immediately after waking up and in a thermoneutral environment
Define resting metabolic rate
The metabolic rate approximately 4 hours after a light meal and after approximately 30 to 60 minutes of resting quietly
What factors affect metabolic rate?
- gender
- body temperature
- stress levels
- body surface area
Intramuscular PC accounts for __% of ATP during a 3 second sprint
55
Intramuscular ATP accounts for __% of ATP during a 3 second sprint
32
Lactic acid accounts for __% of ATP during a 3 second sprint
10
Aerobic metabolism accounts for __% of ATP during a 3 second sprint
3
An increase in lactic acid produces a ____ in pH
decrease
How many grams of lactic acid can our body handle?
60-70 grams
1 mole of glucose breaks down into how many grams of lactic acid
180 grams
There are ___ grams of glucose stored in the blood, ___ grams of glycogen stored in the liver, and ___ grams of glycogen stored in muscle
20
100
350
What can be defined as the maximal rate at which oxygen can be consumed?
VO2 max
VO2 max is ____ when a large muscle mass is involved
higher
What kind of treadmill work produces a higher VO2 max?
inclined treadmill work
Does arm or leg ergometry produce higher VO2 max levels? Why?
leg, because larger muscle groups are used
Mean values of VO2 max are __-__% less in women. Why?
10-20
Because they have higher body fat and lower hemoglobin concentrations
On average hemoglobin = __ g/dL in women and __ g/dL in men
14
16
After the age of 25 years VO2 max declines _% per decade
9%
What are the 5 determinants of oxygen uptake?
1) Pulmonary ventilation
2) Diffusion of oxygen
3) Cardiac performance
4) Skeletal vascular bed
5) Extraction of oxygen by contracting skeletal muscle
What is an efficient VO2 max related to?
a high TV and a low RR
Steady state exercise occurs at about __% of max HR, which is approximately ___-___ bpm in most people
60%
120-140 bpm
A person who is trained accumulates ____ oxygen debt than a person who is untrained
less
There is a _____ relationship between oxygen uptake and HR
linear
How do you calculate minute ventilation?
Tidal volume x RR
Normal TV = ___ mL/breath
Normal RR = __ breaths/minute
Which means normal minute ventilation = _____ mL/minute
500 mL
10 breaths/min
5,000 mL
HR and systolic BP return to normal __-__ minutes following exercise
15-20
Following moderate and maximal exercise there is a fast and slow component. What are each aka?
Fast: Alactacid component
Slow: Lactacid component
What happens during the fast/alactacid component?
ATP-PC and myoglobin are replenished
This restoration of muscle ATP-PC (fast component) takes how long?
2–5 minutes
What happens during the slow/lactacid component?
lactic acid is removed
This removal of lactic acid (slow component) takes how long?
30 minutes to an hour
What does the restoration of muscle and liver glycogen depend on? How long does this take?
It depends on the type of exercise performed (how much glycogen is spent during the exercise) can take anywhere from 10-46 hours
What 5 things does blood lactate accumulation depend on?
- Intensity
- Low tissue oxygen
- Reliance on glycolysis
- Activation of fast twitch fibers
- Reduced lactate removal
What are 3 characteristics of people who have high blood lactate thresholds?
- have more slow twitch fibers
- higher VO2 max
- higher capillary density and mitochondria
What are the 3 fates of lactic acid as it is removed?
- Excreted in urine and sweat
- Converted to glucose and glycogen
- Oxidized to CO2 and water
