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KPE 264 EXERCISE PHYSIOLOGY > Module 3: Anaerobic and aerobic exercise responses > Flashcards

Module 3: Anaerobic and aerobic exercise responses Flashcards

1
Q

With regards to the relative contributions of the energy systems, at what point in time do the non-oxidative and oxidative systems crossover (50/50)?

A

2 minutes

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2
Q

At what point in time does the contribution of the PCr system peak?

A

Initial onset of exercise (1 second) and contributes until 30 seconds

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3
Q

At what point in time does the contribution of the glycolytic system peak?

A

At 60 seconds with a 60% contribution

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4
Q

What are two tests that individuals can do to measure their anaerobic performance?

A
  1. Wingate bike test - 30 seconds of maximal effort on a bike against resistance (0.075kg x BW)
  2. Muscle biopsies - PCr and lactate concentrations
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5
Q

What is peak power a good indicator of?

A

PCr system

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6
Q

What is mean power a good indicator of?

A

Glycolytic system

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7
Q

How much ATP is produced per unit of lactate anaerobically?

A

1.5

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8
Q

What are the two ways in which you can measure aerobic exercise response?

A

Calorimetry which is the quantification of energy production by the body

  1. Direct: based off of heat production (1kcal = increase in temp. of 1kg of water by 1 degree Celsius)
  2. Indirect: based off oxygen consumption (1L of O2 uptake = 5kcal)
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9
Q

What is the equation to calculate the Respiratory Exchange Rate of an individual (RER)? What is this value indicative of?

A

Ratio of CO2 to VO2 consumed, RER = VCO2 / VO2. Helps with estimating a relative % contribution of CHO and fats.

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10
Q

What is the theoretical basis that the measurement of RER relies upon?

A
  1. O2 needed to combust a given unit of food is constant
  2. O2 needed to combust a unit of CHO vs fat is different
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11
Q

What are the two assumptions of RER?

A
  1. Protein is not contributing to energy provision
  2. Oxygen consumption is at a steady state
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12
Q

What are two potential flaws with regards to RER?

A
  1. Hyperventilation
  2. Intense exercise

Both result in the increased expulsion of CO2 which will provide an overestimated RER value

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13
Q

What is the chemical reaction that occurs when one molecule of glucose is broken down?

A

C6H12O6 + 6O2 -> 6CO2 + 6H2O

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14
Q

How is oxygen related to carbon in terms of breakdown of a fuel?

A

The number of oxygens increase with the number of carbons

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15
Q

What is the chemical reaction that occurs when one molecule of palmitate is broken down?

A

C16H32O2 + 23O2 -> 16CO2 + 16H2O

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16
Q

What is the typical RER value for an individual at rest?

A

~0.78, exactly at 0.70 is rare

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17
Q

At an RER of 1.00, 0.85, and 0.70, what are the % contributions of CHO and fat and how many kcals are burned per L of O2?

A

1.00 - 100% CHO, 5.05 kcal/L of O2
0.85 - 50% CHO and 50% fat, 4.86 kcal/L of O2
0.70 = 100% fat, 4.67 kcal/L of O2

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18
Q

For CHO and fats, how much CO2 is produced per molecule of O2?

A

CHO: 1 CO2 per O2
Fats: <1 CO2 per O2

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19
Q

What is the average absolute resting VO2 of an individual?

A

0.2-0.3 L of O2/min (200-300 ml/min)

Absolute VO2 is related to body size - a larger individual will naturally require more oxygen uptake

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20
Q

What is the average relative resting VO2 of an individual?

A

3.5 ml of O2/kg/min, this is known as 1 MET = 1 metabolic equivalent

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21
Q

What is the relationship between VO2 and exercise intensity?

A

Linear relationship, as exercise intensity increases so does VO2

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22
Q

*Practice calculating resting energy expenditure within questions in lab manual 2

A
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23
Q

Define the term VO2 max and what are two key determinants of it?

A

Maximal rate of oxygen consumption by the body - reflects the highest rate of oxidative metabolism
1. O2 delivery which is largely dependent on the cardiorespiratory system
2. O2 utilization which is largely dependent on one’s mitochondrial content (more mitochondria more O2 can be consumed)

24
Q

For a 60kg female and a 80kg male, what are the typical VO2 max values you see with an inactive, active, well trained, and elite individual?

A

Inactive female: 2 L/min
Inactive male: 3 L/min

Active female: 2.5 L/min
Active male: 4 L/min

Well trained female 3 L/min
Well trained male: 4.5 L/min

Elite female: 4 L/min
Elite male: 6 L/min

To convert absolute to relative, multiply by 1000 and divided by BW

25
Q

Why do females tend to have lower VO2 maxes?

A

Due to body composition - naturally have more fat which is not as metabolically active as muscle

26
Q

What instrument can be utilized to reach a greater VO2 max?

A

Treadmill - engaging more muscle mass and thus consuming more oxygen

27
Q

What is the five points that formulate the criteria for determining VO2 max?

A
  1. If a plateau in oxygen consumption is prevalent - if this criterion is not reached, you refer to this value as the VO2peak
  2. Reach age predicted max HR (220-age)
  3. High blood lactate concentrations (8x rest)
  4. RER > 1.1
  5. Voluntary exhaustion (does the individual look tired)
28
Q

How does oxygen uptake work at a rest to work transition?

A

When you work at an increased rate, you produce what is known as an oxygen demand and this value tends to be greater than the oxygen that is supplied at the beginning of exercise - oxygen deficit. As a means of meeting this demand, anaerobic systems are activated for ATP production until oxygen can kick in. The greater the demand, the greater the oxygen deficit.

29
Q

With regards to the rest to work transition, what is the idea of Excess Post Exercise Consumption (EPOC)? What are two reasons that it occurs?

A

The idea that oxygen consumed post exercise is greater than that of the demand
1. Helps replenish our PCr, ATP, and muscle glycogen stores
2. Helps clear lactic acid and expel CO2

30
Q

Define the term lactate threshold: What does it represent?

A

The point in exercise where there an abrupt lactate concentration within the blood. Reflects the ability to sustain oxidative metabolism.

31
Q

Beyond the lactate threshold, what energy system is relied upon?

A

Anaerobic energy system

32
Q

For untrained and trained individuals, where does the lactate threshold occur?

A

Untrained: 60% of their VO2 max
Trained: 70-80% of their VO2 max

33
Q

What are the five factors affecting muscle lactate concentrations?

A
  1. Oxygen availability
  2. Enzyme activity
  3. Muscle fiber types (type II muscle fibers produce more lactate)
  4. Muscle lactate transporters
  5. SNS activity
34
Q

What are the four characteristics which make endurance athletes successful?

A
  1. High VO2 max
  2. Having a high lactate threshold which is close to the VO2 max
  3. High economy of effort
  4. High percentage of type I muscle fibers
35
Q

What are two ways in which economy of effort can be demonstrated?

A
  1. Perform more work for a given energy cost
  2. Lower energy cost for a given amount of work
36
Q

As a relative percentage of energy, what is the effect of exercise intensity on fuel use?

A

At lower intensities (25% of VO2 max), there is going to be a greater dependence on fat (70%) relative to glucose (30%). As exercise intensity increases, the dependence on fat will decrease (i.e., 50% of VO2 max will rely 50% on fat and 50% on glucose, 75% of VO2 max will rely 70% on glucose and 30% on fat).

37
Q

In terms of the rate of energy use, where do we see the most kcal/min of fat and CHO burned?

A

At 50% of VO2 max (moderate intensity), we see the most kcal/min of fat burned. Increasing exercise intensity will increase the kcal/min of CHO burned.

38
Q

What is the effect of exercise duration on fuel usage?

A

As exercise duration increases, there a greater reliance on blood borne substrates (i.e., blood glucose, plasma FFA)

39
Q

How do researchers determine specific fuel use?

A
  1. Measure overall rate of energy use - VO2
  2. Measure % of fat and CHO used - RER
  3. Measure muscle glycogen utilization - muscle biopsies
  4. Measure muscle uptake of FFA - AV catheters
40
Q

What is a hormone? What are two sources of hormones?

A

Chemical substances that are secreted into body fluids and they have effects on local or distant target tissues.
1. Endocrine glands
2. Other tissues (i.e., kidney which secretes EPO - this hormone stimulates the production of RBC in red bone borrow which results in an increased oxygen carrying capacity)

41
Q

What are the two classifications of hormones? Where are they released from?

A
  1. Non steroid hormone
    Derived from proteins, peptides, and AA’s
    Not lipid soluble meaning they cannot cross the cell membrane
    Released from the pancreas, hypothalamus, pituitary gland and adrenal medulla
  2. Steroid hormones
    Derived from lipids (cholesterol)
    Lipid soluble meaning they can cross the cell membrane
    Released from ovaries, testes, and the adrenal cortex
42
Q

What are the three main functions of non steroid and steroid hormones during exercise?

A
  1. Alter enzyme activity (Non steroid)
  2. Alter membrane transport (Non steroid)
  3. Alter protein synthesis rate (Steroid and non steroid)
43
Q

With regards to the hormone insulin, what is the site of release and what are the three primary actions?

A

Site of release: pancreas (B cells)
Anabolic in nature
1. Increase the uptake of glucose/FFA/AA
2. Increase glycogen/TG/Pro. synthesis
3. Decrease lipolysis

44
Q

With regards to the hormone glucagon, what is the site of release and what are the two primary actions?

A

Site of release: pancreas (A cells)
Catabolic in nature
1. Increase liver glycogenolysis
2. Increase gluconeogenesis

45
Q

With regards to the hormone epinephrine, what is the site of release and the two primary functions?

A

Site of release: Adrenal medulla
Catabolic in nature
1. Increases muscle and liver glycogenolysis
2. Increases lipolysis (muscle and adipose)

46
Q

With regards to the hormone norepinephrine, what is the site of release and the two primary functions?

A

Site of release: SNS fibers and adrenal medulla
1. Increases lipolysis (adipose)
2. Increases cardiorespiratory function

47
Q

What is the effect of exercise intensity on the four key blood hormones?

A

Insulin concentrations will go down, E, NE, and GL concentrations will go up
^ order of increase from least to greatest

48
Q

What is the cyclic AMP or second messenger system? Describe the pathway and the time it takes for this process to occur?

A

A process that occurs in non steroid hormones. Essentially, we have a hormone which binds to a receptor on the cell membrane. This causes an enzyme known as Adenylate cyclase to be activated, which converts ATP to cAMP, activating a protein kinase. This triggers cellular responses to occur (i.e., E which increases muscle glycogenolysis, E/NE which increase lipolysis (muscle, adipose), GL which increases liver glycogenolysis). This process happens in under a minute.

49
Q

Skeletal muscle contraction increases the concentration of what going to the active muscle?

A

Insulin - pathway is determined by two factors which are blood concentration and muscle blood flow . Remember that the overall concentration of insulin decreases during exercise.

50
Q

What happens to our blood glucose levels during exercise?

A

Unchanged, however if exercise is prolonged, they decrease

51
Q

What are the four ways in which we maintain our blood glucose during exercise?

A
  1. Minimize the glucose that is used by less active tissues - decrease insulin concentrations
  2. Mobilize alternative fuels to glucose - Increase NE which increase FFA from adipose tissue (lipolysis)
  3. Stimulate muscle glycogen use - increase E
  4. Release glucose from liver sources - Increase glucagon and E (glycogenolysis and gluconeogenesis)
52
Q

What are the key metabolic adaptations to exercise training with regards to mitochondria, fuel storage, and fuel use?

A

Mitochondria: Increased number and size, increase in oxidative enzymes (citrate synthase, succinate dehydrogenase)

Fuel storage: Increase glycogen

Fuel use (@same absolute workload - i.e., 200 W before and after training): decreased CHO utilization (glycogen sparring), decreased lactate production.

Decreased CHO utilization means there’s an increased use of fats which means a lower RER will result. Decreased CHO utilization means that the CHO that is being utilized is being done so more efficiently via oxidative metabolism, resulting in an increased LT

53
Q

What are the metabolic adaptations to mitochondrial content that occur from one minute of intense exercise vs forty five minutes of steady state exercise?

A

Both increase mitochondrial content equally

54
Q

What happens to one’s RER after exercise training? What are the four reasons as to why this occurs?

A

RER decreases at a given workload or the workload increases at a given RER.

Decreased workload per mito, increased lipid delivery to mito, increased enzymes for lipid oxidation, decreased stimulation of CHO for use (E)

55
Q

What happens to one’s LT after exercise training? Why?

A

Decrease in LT at a given workload or a increase in workload at a given LT

Increase in mitochondria (#1 determinant), increase in lactate clearance, increase in pyruvate oxidation, decrease in pyruvate production

KPE 264 EXERCISE PHYSIOLOGY (7 decks)

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