Exercise physiology Flashcards
Which is the order of metabolic pathways used when undergoing exercise? [3]
- Phosphocreatine: immediate energy system
- Anaerobic glycolysis: Non-oxidative source
- Aerobic metabolism: Aerobic system
Briefly explain how the immediate energy system works
Enzyme name? [1]
Decomposition of phosphocreatine releases high amounts of energy which can generate ATP. This energy transfer occurs within a fraction of a second
Enzyme: creatine kinase
During anaerobic glycolysis, excess [] is converted to [] in a reaction with [] and []
What happens to blood pH during anaerobic glycolysis? [1]
During anaerobic glycolysis, excess pyruvate is converted to lactate in a reaction with NADH and H+
Blood pH drops
Why do we need anaerobic and phosphocreatine pathway on top of aerobic metabolism? [1]
What is VO2? [1]
Aerobic metabolism takes time to occur, anaerobic and phosphocreatine pathway provide energy in the mean time
VO2: volume of oxgen consumed
How do you calculate VO2? [1]
What is the name of the equation? [1]
Fick equation:
VO2 = Q x (CaO2-CvO2)
Qis thecardiac outputof the heart (blood flow to muscle)
CaO2is the arterial oxygen content
CvO2is the venous oxygen content
(CaO2– CvO2) is also known as thearteriovenous oxygen difference.
What is VO2 max?
When do you reach VO2 max?
VO2 max: is the highest peak oxygen uptake that an individual can obtain during dynamic exercise using large muscle groups during a few minutes performed under normal conditions at sea level
VO2 max is reached when: O2 consumption remains at steady state despite and increase in workload
What is the lactate / anaerobic threshold?
What does ^ cause to occur to blood pH? [1]
Lactate / anaerobic threshold: the point where lactate (lactic acid) begins to accumulate in the bloodstream.
Causes metabolic acidosis
What are the two major consequences of increased excercise? [2]
- Regional muscle vasodilation (decrease SVR)
- Increase in cardiac output – through increases in SV and HR
Explain how increase muscle blood flow occurs during exercise [Local control & Systemic control?]
Regional muscle vasodilation achieved by:
Local control:
* Vasoactive substrates and products of muscle metabolism (CO2, Lactate, K+)
* Muscle hypoxia
* Vasoactive mediators released by the endothelium (Nitric Oxide, ATP, Adenosine and prostaglandins)
Systemic regulation:
* Adrenergic receptor activation (β2R –> Vasodilation)
AND
Vasoconstriction of other vascular beds which redirects blood flow
Which systems recieve more blood flow / less blood flow during exercise
More blood flow:
- skeletal muscle
- heart
- skin (for heat loss)
Less blood flow:
- GI tract
- Kidney
What happens to blood flow to brain during exercise? [1]
Stays the same !!
Explain how cardiac output is increased during exercise? [2]
What is relationship between HR and SV as they both increase? [1]
Achieved by increasing HR and SV.
- HR increase due to: more adrenaline on B1 adrenoreceptors AND decrease parasympathetic NS.
- SV: increase preload, decrease afterload, and increase contractility
However! SV starts to drop after a while: as HR increases, diastolic time decreases, so get reduced blood out.
What are the increases in sympathetic outflow that occur due to exercise? [3]
What are the local responses that occur due to exercise? [1]
Sympathetic:
- Increase HR: increased CO
- Constriction of aterioles (splachnic and renal)
- Constrictio of veins: increase in venous return
Local response:
- Increase in vasodilator metabolites: decrease in SVR
AND
Decreased parasympathetic output
If during exercise SVR / Total peripheral resistance decreases, how come systolic BP increases? [1]
SVR reduces, but SV and MAP increases. CO increases in greater magnitude than TPR decreases
What remodelling can occur in response to long term exercise?
- Cardiac muscle hypertrophy (due to sustained increase in BP)
- Chambers increase in size
How do blood gas differences in arteries / veins effect oxygen diffusion in exercise?
Get increased difference in AV gradient: drives oyxgen diffusion into cells
What happens to the levels of paO2 in arterial blood during high levels of exercise?
At high levelss of exercise the paO2 in the arterial blood declines slightly
