KIN 105 Lecture Notes - Exercise Intensity, Glycolysis, Enzyme
Lecture 8 – Steady State Exercise
Rest to Exercise Transition – Submaximal Exercise
Can our muscles provide the immediate supply of ATP
needed to perform this task?
- Yes, if no you would fall because your muscles
would not be able to contract. Using the HEPT
system, stored ATP, Anaerobic, Glycolysis, and
Oxidative Phosphorylation.
- There is essential an instantaneous increase in
ATP demand that is directly proportional to
exercise intensity
VO2 Kinetics and Oxygen Deficit and Metabolism
VO2 kinetics – is the exponential increase in VO2 from a prior value (i.e. rest or a lower work
rate) to a new steady state.
Oxygen Deficit – is the difference between a measured VO2 and the steady state value after the
onset of exercise
Magiia ’s: seial oilizatio theo
PCr immediate and only substrate for ATP re-synthesis in first 10 seconds
When PCr depleted, glycolysis is activated to provide a continued ATP supply
NOT TRUE – glycolytic rate is increase (activated) immediately at the onset of exercise and
blood flow increases and enzymes involved in oxidative phosphorylated are activated. ALL ATP
SUPPLY PATHWAYS ARE ALWAYS ACTIVE. The relative contribution of each pathway can change
with time and exercise intensity.
Example:
VO2 required 3.0 L/min
@ beginning of exercise: (0.25 L/min) / (3 L/min) = 8%, Therefore, 92% of ATP (or energy) is
coming for anaerobic sources (HEPT, glycolysis)
@ 1 min: (1.9 L/min) / (3.0 L/min) = 63%, Therefore 37% of ATP (or energy) is coming from
anaerobic sources
@ 2 min: (2.6 L/min) / (3 L/min) = 87%, only 13% of ATP is produced anaerobically
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O2 Deficit and EPOC during Moderate – Hard and Supramaximal Exercise
O2 defiit ad stead state is iflueed eeise itesit
VO2 plateaus in 3 min – 4 min
When we exercise at larger intensities (wingate), we require a
larger oxygen deficit to reach O2 demands. However, when
individuals level off its going to be through glycolysis.
EPOC: Excess Post-Exercise Oxygen Consumption
- Elevated VO2 for several minutes immediately following
exercise
- Rapid component of EPOC
• Re-synthesis of PCr recall: ADP + Pcr ATP + Cr
- Reaction shift to left
• Replacing muscle (myoglobin) and blood O2 stores
- Slow component of EPOC
• Elevated body temperature and catacholamines
• Conversion of lactate to glucose (gluconeogenesis)
• Elevated HR and ventilation (diaphragm) above resting values
Kinetics of Fick Equation Variable at the Onset of Exercise
Instantaneous increase of CO and SV and HR at the onset of exercise (within
1 second)
- Withdrawal of parasympathetic activity
Takes approximately 1-4 minutes until steady state of HR, SV and CO at
constant workrate
Rapid decrease of HR, SV and CO occur after exercise
Blood Flow Kinetics at the Onset of Exercise
Cardiac cycle last for one second
This is brachial artery blood flow following 1 contraction of the forearm muscle
- Note iitial dip, hat’s happeig thee?
• Skeletal muscle contraction – compressing microvascular
(capillaries and arterioles)
- Almost immediate increase in blood flow, how?
• Muscle pump, pressure gradient effect
- Muscle pump = mechanical
The right picture is the femoral artery blood flow response to dynamic
exercise (i.e. cycling)
- Looks very familiar to VO2 and CO response
- Day 10 and day 0 vary because of time frame metabolites begin to
effect
- Metabolites = chemical = induced vasodilation
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** BF = P/R
increasing P will cause
blood flow to increase
Hemodynamic Response of Heavy Cycling
Cardiac output is main determinant of blood pressure (SBP, DBP)
Resting CO output is 5L/min, therefore CO graph demonstrates individual performing exercise
Also, SBP and DBP are already elevated in blood pressure graph as well
MAP = CO x TPR
= 10 x 10
= 100 mmHg
Total peripheral resistance is decreasing during exercise because vasculature increasing in
diameter due to vasodilation at active skeletal muscles
Metabolic Response to Submaximal Steady-State Exercise (assuming cycling at 50% VO2 max)
Resting RER is 0.8
Exercise will increase RER (just as an example: from 0.8 to 0.9), which indicated a shift from FFA
oxidation to CHO oxidation
The increase in RER is dependent on what factor?
- WR (exercise intensity) - increase
- PCr - decrease
- Cr – increase
- ATP – no change
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Document Summary
Yes, if no you would fall because your muscles would not be able to contract. Using the hept system, stored atp, anaerobic, glycolysis, and. There is essential an instantaneous increase in. Atp demand that is directly proportional to exercise intensity. Vo2 kinetics is the exponential increase in vo2 from a prior value (i. e. rest or a lower work rate) to a new steady state. Oxygen deficit is the difference between a measured vo2 and the steady state value after the onset of exercise. Pcr immediate and only substrate for atp re-synthesis in first 10 seconds. When pcr depleted, glycolysis is activated to provide a continued atp supply. Not true glycolytic rate is increase (activated) immediately at the onset of exercise and blood flow increases and enzymes involved in oxidative phosphorylated are activated. The relative contribution of each pathway can change with time and exercise intensity.
