Chapter 5 Flashcards
What is direct calorimetry?
measuring the body’s heat production
How much substrate energy produces ATP?
40%
How much substrate energy converts to heat?
60%
What does heat production do in conjunction with energy production?
it increases
What is a pro of calorimeters?
it can provide an accurate measure of total body energy expenditure over time
What is a con of calorimeters?
it can’t follow rapid changes in energy expenditure (it’s slow) and it’s expensive to construct
Direct calorimetry is useful for measuring what?
resting metabolism and energy expended during prolonged steady-state aerobic exercise
What is indirect calorimetry?
estimating total body energy expenditure
How is indirect calorimetry measured?
by measuring the respiratory exchange of O2 and CO2
What is indirect calorimetry limited to?
steady-state aerobic activities that last a few minutes or longer
How is the respiratory exchange ratio (RER) calculated?
the volume of CO2 produced per minute divided by the volume of oxygen consumed per minute
What does the RER value vary with?
the type of fuels being used for energy. (ex: carbs, fats, protein)
Why is the RER value for fat substantially lower than carbs?
more oxygen is needed to oxidize fat
What are RER values compared to once they’re calculated?
A table that determines the food mixture being oxidized
Oxidation of carbs yield?
5.05 kcal / L of O2
Oxidation of fat yield?
4.69 kcal / L of O2
Oxidation of protein yield?
4.46 kcal / L of O2
Why is RER sometimes considered nonprotein RER?
it ignores any protein oxidation
VO2 is?
volume of oxygen consumed per minute
VCO2 is?
volume of carbon dioxide produced per minute
What does gluconeogenesis produce with RER?
an RER value less < than 0.70
What is typical range of the RER value when the body is at rest?
0.78 to 0.80
During exercise why are RER values usually higher?
As exercise intensity increases, the muscles carb demand increases so more carbs are oxidized
Why are RER values that approach 1.0 not accurate?
lactate accumulation increases CO2 production and increases the amount of CO2 being released
What is an isotope?
an element with atypical atomical weight
Are isotopes radioactive or nonradioactive?
they can be either or
What is a pro for measuring isotopes?
it’s accuracy and low risk makes it easy to calculate day-to-day energy expenditure
At rest RER values and VO2 are what?
0.80, Vo2 = 0.3 L / min
What is the metabolic rate at rest?
2,074 kcal / day
What is basal metabolic rate (BMR)?
standardized measure of energy expenditure at rest
What is BMR related to?
fat-free mass
The higher the fat-free mass is =?
the more total calories expended in a day
Why do women tend to have a lower BMR than men of similar weight?
women tend to have a lower fat-free mass and a greater percent of body fat than men
Resting metabolic rate (RMR) values range from what?
1,200 to 2,400 kcal / day
What is the total daily metabolic activity value range for normal people?
1,800 to 3,000 kcal / day
What is the total daily metabolic activity value range for competitive athletes?
can exceed up to 10,000 kcal / day
As exercise intensity increases, metabolic rate does what?
it increases
What is VO2 drift?
a slow increase in VO2 during prolonged constant power output exercises
What is maximal O2 uptake (VO2max)?
the maximal limit of your ability to increase your VO2
What is VO2max a good measurement of?
cardiorespiratory endurance (aerobic fitness)
How does VO2max increase?
it increases with physical training for only 8 to 12 weeks then plateaus
What happens after VO2max plateaus?
it doesn’t continue to increase but endurance performance is improved
How is VO2max expressed?
liters per minute (L/min)
Why is VO2max normalized for body weight?
individuals’ energy requirements vary with body size
How is VO2max for body weight expressed?
milliliters of oxygen consumed per kilogram of bodyweight per minute (ml02 x kg x min)
Why is VO2max for body weight expressed like (ml02 x kg x min)?
it allows more accurate comparison for different body sizes
What is the VO2max for body weight value range for untrained young men?
44 to 50 ml x kg x min
What is the VO2max for body weight value range for untrained young women?
38 to 42 ml x kg x min
What happens to the VO2max of inactive individuals after the age of 25 to 30 years old?
the VO2max value decreases at a rate of about 1% per year
Why do adult women generally have VO2max values below adult men?
sex differences and blood hemoglobin content
What is peak oxygen uptake (VO2peak)?
the highest level of oxygen consumption that can be achieved during a mode of exercise
What is the largest VO2peak for an individual?
VO2max
What is typical mode of exercise during which VO2max occurs during VO2peak?
running or stair stepping
Why does running or stair stepping cause VO2max to occur during VO2peak?
more oxygen consumption when running or stair stepping because we’re using large muscle groups
What is a MET?
a measurement of cardiorespiratory work fitness
1 MET =?
3.5 ml/kg/min OR VO2
ml/kg/min =?
VO2
Light intense activities use how many METS?
less than < 3 METS
Moderate intense activities use how many METS?
3 to 5 METS
Vigorous intense activities use how many METS?
more than > 6 METS
What is the benefit of METS over VO2?
people have a choice on the activity they’d like to do in their MET range and it’s free
Is any activity 100% aerobic or anaerobic?
no
Estimates of ANAEROBIC effort involve what?
the excess postexercise oxygen consumption (EPOC) or lactate threshold
What is happening in postexercise oxygen consumption (EPOC) during early exercise?
the oxygen demand is greater than oxygen consumed
Why is the oxygen demand greater than oxygen being consumed in early exercise?
the body incurs an oxygen deficit
What is steady state?
the oxygen needs are being met
What is happening in postexercise oxygen consumption (EPOC) during early recovery?
the oxygen consumed is greater than the demand
What does excess postexercise oxygen consumption (EPOC) replenish?
hormone balance, ATP / PC stores, lactate to glucose, and clearing CO2
When is lactate produced?
during anaerobic glycolysis
What is lactate threshold?
when blood lactate increases extremely fast
What is LT usually expressed as?
a percentage of VO2max
If lactate is accumulating, what is happening to the body?
the body is getting fatigued
LT reflects the interaction of what two energy systems?
aerobic and anaerobic energy systems
What is the LT for untrained people?
50% to 60% of their VO2max
What is the LT for elite endurance athletes?
70% to 80% of their VO2max
What is the performance like for 2 athletes with the same VO2max but one has a higher LT?
the athlete with a higher LT will have a better endurance performance
What is economy?
how efficient you are in movements
What happens to an athlete’s economy as they become more skilled?
the body will learn energy economy and energy demands are reduced
What is the multifactorial phenomenon?
economy increases with distance of race
What are the characteristics of a successful endurance athlete?
high VO2max, high LT, high economy of effort, and high % of type 1 fibers
Fatigue definition: “decrements…”
decrements in muscular performance with CONTINUED EFFORT accompanied by sensations of tiredness
Fatigue definition: “inability…”
inability to maintain REQUIRED POWER OUTPUT to continue muscular work at given intensity
Fatigue is reversible by what?
rest
What causes fatigue?
decreased rate of energy (energy systems), accumulation of metabolic by products (lactate and hydrogen), failure of muscles contractile mechanism, and alterations in neural control of muscle contraction
What may be a potential cause of Pcr depletion?
accumulation of inorganic phosphate
What helps defer Pcr depletion?
pacing
Glycogen reserves are limited and deplete quickly where?
the liver and muscle
Glycogen depletes more quickly with what?
intensity
Glycogen depletes more quickly during what stage of exercise?
the beginning stage of exercise
Glycogen depletion in every muscle group may cause what?
bonking
What does liver glycogen do?
it donates glycogen to other parts of the body
Muscle glycogen + hypoglycemia =?
fatigue
What does fat metabolism do when glycogen is depleting?
it increases
As muscle glycogen is decreasing, liver glycogenolysis is doing what?
increasing
What temperature is the longest to exhaustion?
52 degrees
What temperature is the shortest to exhaustion?
88 degrees
Lactic acid accumulates when?
during high intensity exercises
What do buffers do for muscle pH?
they minimize the drop in pH (7.1 to 6.5)
Fatigue may inhibit what from being released from the SR?
calcium
How does neural transmission play a role in fatigue?
nerve impulse transmission to the muscle fiber membrane may be prevented
What might cause fatigue from neural transmission?
cholinesterase is becoming hyper or hypoactive and threshold change
When does acute muscle soreness occur?
during and/or after strenuous exercise
How long does it take for acute muscle soreness to go away?
within minutes/hours
What usually causes acute muscle soreness
edema
What is DOMS?
delayed onset muscle soreness
What is the major cause of DOMS?
eccentric contractions
What does NOT cause DOMS?
increase in blood lactate concentrations
When does DOMS occur?
24 to 48 hours post exercise
What is happening in the body when DOMS occurs?
tissue breakdown and structural damage
What causes inflammation with DOMS?
z-line damage, calcium buildup, enzyme activity, and ATP inhibition
How is structural damage indicated with DOMS?
muscle enzymes in the blood
Damaged muscle cells in DOMS attracts what?
neutrophils
What are neutrophils?
a type of white blood cells that help repair damage
The buildup of what triggers nociceptors?
calcium, neutrophils, and enzymes
What do macrophages do?
they remove debris
The buildup of triggering nociceptors causes what with DOMS?
soreness
What is hypertrophy?
muscle growth
What are free radicals?
unpaired electrons
What makes free radicals?
oxygen atoms splitting into single atoms
Why are free radicals bad?
it causes damage to cells, proteins, and DNA
What are free radicals associated with?
cancer, neurodisease, atherosclerosis
Where do free radicals come from?
processed food mainly, chemicals, medicine, air, metabolic by-products
How are free radicals crucial to the immune system?
they attack foreign invaders
Oxidative stress is prevented by what?
antioxidants
Why can’t you max out while sore?
z-lines are broken
Broken z-lines =?
loss of strength
Exercise associated muscle cramps (EAMC) occurs when?
during or immediately after exercise
What cause exercise associated muscle cramps (EAMC)?
excitation of muscle spindles and inhibiting of Golgi tendon organs
What are exercise associated muscle cramps (EAMC) relieved by?
stretching
What causes heat cramps?
loss of sodium and chloride through sweat
How are heat cramps relieved?
high-sodium solution, ice, and massage
What can be used to reduce DOMS?
tart cherry juice
