Unit 2: Chapter 4 Flashcards
Exercise challenges ____in the body, especially in ___ (structures)
bioenergetic pathways; skeletal muscles
Heavy exercise can increase energy expenditure by ____ above rating levels.
15-25%
At rest:
Almost 100% of ATP produced by ___
Aerobic Metabolism
At Rest:
Blood lactate is ___
Resting Oxygen consumption is at:
low (<1.0 mmol/L…. but not zero);
Resting O2 (0.25 L/min) or (3.5 ml/kg/min)
Exercise intensity domains: Moderate.
(<60% VO2 Max)
Exercise intensity domains: Heavy
(60-75% Vo2 Max)
Exercise intensity domains: Very Heavy
(76–100% VO2 Max)
Exercise intensity domains: Severe
(… over 100%)
How do we qualify how we describe exercise?What are two indicators exercise has occured?
Lactate threshold and Vo2
What happens when you reach your lactate threshold?
can’t maintain exercise intensity;
acidic, fatigue, burning.
From rest to exercise:
ATP production ___, and oxygen uptake ___
increases immediately; increases rapidly
How long does it take to reach a steady state?
1-4 mins
After a steady state is reached, the ATP requirement is met through ____ ATP production.
aerobic
What are the initial products of ATP?
What systems kick in first during exercise? List the order.
Anaerobic before aerobic
ATP-PC + Glycolisis before oxidative phosphorylation
Oxygen deficit is a __ in oxygen uptake
lag
(In between space on the graph as exercise and ATP increase)
The role of the phosphocreatine system and glycolysis in ATP production during exercise lasting __ mins
3-mins
Roles:
—
Oxygen deficit and excess post-exercise O2 consumption (EPOC)
Beginning:
End:
O2 Uptake (VO2)
The measure of the ability to take in and use oxygen
O2 Deficit. What system causes it? Why can’t it immediately jump to the right oxygen lvl?
anaerobic contribution to energy cost exercise
Excess Post-Exercise Oxygen Consumption (EPOC)
“O2 uptake above resting values used to restore the body to the pre-exercise condition”
Metabolism doesn’t just drop, there is a gradual change back to normal.
What does the VO2 (Heading)
VO2 ____ at the beginning of exercise indicates that both ___ and ___ bioenergetic pathways are active to produce ATP
rises slowly;
anaerobic and aerobic
O2 deficit: Trained vs. Sedentary
Trained:
1) Trained subjects have a lower oxygen deficit
2) The more trained, you jump to anaerobic metabolism faster
Sedentary:
1)
(Trained or Sedentary) Do subjects have a lower oxygen deficit? Why?
Trained:
1) Trained subjects have a lower oxygen deficit.
2) The more trained, you jump to aerobic metabolism faster
3) Less Lactate production
Sedentary:
1)
………
What is VO2 Max?
VO2 max is a plateau in O2 consumption with an increase in work rate
How do you verify that VO2 max has been reached?
Not easy to tell:
1) Reaching age-predicted max heart rate (+/− 10 beats/min)
2) Achieving blood lactate concentration of 8 mM or higher
3) Attaining a respiratory exchange ratio of 1.15 or higher
What is a Lactate threshold? What is the difference in trained and untrained?
work rate (intensity) at which blood lactate rises during incremental exercise
Exponential increase.
Can you maintain exercise at your lactate threshold?
Barley. A lot of fatigue build-up
What is OBLA?
Onset of blood lactate accumulation.
When blood lactate levels reach 4 mmol/L
Why do we have a lactate threshold? What 4 factors contribute to an elevated lactate threshold?
With lengthy explanation
1) Low muscle oxygen (Hypoxia)
.
2) Recruitment of fast twitch muscle fibers——Makes more lactate
.
3) Reduced rate of lactate removal from the blood—(Clearing it as fast as you’re making it). (I THINK?? Listen to 11 mins)
.
4) Accelerated glycolysis
—NADH is being made after that. You can shuttle it to the mitochondria (It turns pyruvate to lactate)
.
All this spikes the blood lactate.
Why do we have a lactate threshold? What 4 factors contribute to an elevated lactate threshold?
1) Low muscle oxygen
2) Accelerated glycolysis due to epinephrine
3) REcurtment if fast twitch muscle
4) …..
Does lactate production during exercise cause muscle soreness? How does location contribute to fatigue? What causes soreness?
NO!! It does not cause fatigue or soreness, it’s actually energy.
It’s linked because lactate makes everything more acidic and simulates pain receptors.
Soreness is because the muscle is torn
What does the respiratory exchange ratio measure? (RER)
RER —A non-invasive technique to estimate fuel utilization during exercise.
(VCO2/VO2) —The ratio of carbon dioxide produced to the oxygen consumed
(Assumes No protein is used–even tho you’re always burning some protein)
In order to measure respiratory exchange ratio the participant must…
be exercising at a steady state
What is the caloric equivalent of oxygen?
Fat alone—
Carbohydrates alone—
Which is more efficient?
Fat—4.7 kcal
Carbohydrate—5.0
What percentage of the respiratory exchange ratio does it take to burn either fat or carbs?
Fat—.70
Carbs—1.0
What are the factors that decide which fuel selection during exercise?
(which system will it choose?)
1) Exercise Intensity
2) Exercise duration
3) Availability of fuels—What do you eat the most?
4) Level of endurance training? —(How well you burn fat)
Low-intensity- exercise? (like walking low)
What. does it burn?
Which system?
Burns—Fats
(<30% VO2 Max)
High-intensity exercise?
What. does it burn?
Which system?
Burns—Carbs primarily
(>70% VO2 Max)
What is the cross-over concept?
Buring both fat and Carbs
—Lighter intensity—Fat
—More intense exercise—Carbs
What happens during Prolonged, moderate-intensity exercise? What are it’s effects? How long does it take?
40-60% VO2 Max
—Longer you exercise, shifts form burning Carbs to fats
—Shift take 10-20 mins
Why/ how do we shift what we burn during crossover?
Due to an increased rate of lipolysis:
—Breaks down Triglycerids—Glycerol + FFA
—Raises blood lvels and hormones
Fats___ in the ___ of Carbohydrates
Burns;
flames
Glycogen is depleted during –––– (e.g., > 2 hours):
prolonged,
high-intensity exercise
What happens when glycolgen is depleted?
Reduced rate of glycolysis and
—production of pyruvate
Reduced citric acid (Krebs) cycle
—intermediates
Reduced fat oxidation
——(that would’ve been metabolized by Krebs cycle)
No Glycolsis no
krebs cycle
You need ___ to break down fat
Carbohydrate intermediates
The — of muscle and blood –– stores contributes to fatigue
depletion; carbohydrate
Prolonged exercise at a ____ intensity = 20% VO2 Max
Burns what?
prolonged; low
Burns fat
Where is carbohydrates stored?
muscle glycogen (main)
blood glucose (diet and liver)
Where are free fatty acids stored?
(2 places)
What is fat stored as?
Muscle fat stores——(intramuscular tryglicrides)
White adipocytes
—found all over the body
—fat is stored as triglycerides in adipocytes
(More trained, more fatt in muscle. but they also have more enzymes to burn it)
Which fat do you burn first?
You burn fat in the muscle first then it goes to the fat tissue
List in order which has the most calories.
Muscle glycogen, liver glycogen, adipose tissue, blood glucose
1.
Low exercise intensity burns:
25% VO2 Max
largest fat burn
Mainly plasma free fatty acids
glycogen
Glycogen mainly used for higher-intensity
Know the progression of the % of energy derived from fuel sources during prolonged submaximal exercise (slide 4.16)
Muscle glycogen
Blood glucose
Plasma-free fatty acids
Muscle triglycerides
Muscle Glycogen—Good for high intensity but depletes in time
Blood glucose— increases as time goes one
Plasma Free fatty acids —used during long exercise
Muscle tricglrides—relatively consistent
Cori Cycle: lactate as fuel: What is the core cycle?
What are two ways we can get ride of lactate?
after fast glycolysis= a lot of lactate in the blood
- The Cori cycle clears lactate and turns it back to glucose. = called gluconeogenesis
- Slow twitch fibers oxidize lactate by shuttling it to the mitochondria and it turns into pyruvate again
