Exercise Flashcards
What is dynamic exercise?
Rhythmical movement of joints and contraction/ relaxation of muscles (swimming, running, cycling)
What is static exercise?
Maintained contraction for a length of time
What are the 3 sources of energy that support skeletal muscle function
- Immediate energy system
- Anaerobic resp
- Aerobic resp
Which source of energy for skeletal muscle gives fastest ATP supply
Immediate energy system
Function of immediate energy system
Rapid mobilisation of high energy phosphates
Does immediate energy system require oxygen
No
What is the function of creatine phosphate
Provides source of high potential phosphate to maintain contraction
What catalyses reaction in which creatine phosphate provides source of high potential phosphate
Creatine kinase
Does reaction from creatine phosphate to creatine + phosphate produce or require ATP
Produces
How is ATP generated by anaerobic respiration
Via glycolysis
What is excess pyruvate converted to in anaerobic respiration
Lactate
How do lactic acid levels change in 100m sprint
1.6mM to 8.3mM
Where is majority of energy derived from in sustainble exercise
Aerobic respiration
What is VO2
Volume of oxygen consumed
If you are 70kg what is normal VO2
250ml/min
How many ml of oxygen are consumed per minute for each kg of body?
3.6ml
What is VO2max
Maximum oxygen uptake consumed during exercise
When is VO2max reached?
When oxygen consumption remains at steady state despite increase in worklaod
V02= (define each part)
VO2= Q x (Ca02-Cv02) Q= cardiac output Ca02= arterial o2 content Cv02= venous o2 content
What is Ca02-Cv02 known as?
Arteriovenous oxygen difference
What is the V02 max in
a) Elite indurance athletes
b) Mildly active middle aged adults
c) COPD/ advanced heart disease
a) 80-90ml02/(min x kg)
b) 30-40
c) 10-20
Define anaeorbic threshold
Point where lactate starts to accumulate in the body
Is lactic acid produced or metabolised faster? Result of this?
Produced
Metabolic acidosis
Two main ways that the cardiovascular system responds during exercise
1) Rise in cardiac output
2) Redistribution of larger proportion of cardiac output to active muscles
Is sympathetic or parasympathetic system more active in exercise
Sympathetic
How is stroke volume increased in exercise?
There is increased venous return and increased preload therefore increased SV
How is heart rate increased during exercise
Sympathetic innervation has a positive inotropic response to heart
Is stroke volume or heart rate more responsible for cardiac output increase during
a) mild exercise
b) moderate exercise
c) intense exercise
a) both HR and SV
b) SV reaches max level here
c) these changes fully done by HR
How does heart adapt to exercise in the long term
Adapts to sustained increases in blood pressure by increasing muscle mass largely via increase in cardiac myocyte size (hypertrophy)
How does the athletes hypertrophied heart differ to a failing hypertrophied heart
Both have increased muscle mass
Athelete has normal cardiac function, failing heart has reduced
Athletes heart changes are reversible, failing heart non reversible
How does heart rate of athlete compare to untrained individuals
Slower (bradycardia)
What % of cardiac output goes to muscles at rest? At what rate
20-25%
1l/min
What % of cardiac output goes to muscles during maximal exercise? At what rate
80-90%
22l/min
2 ways that the body redistributes blood during exercise
Systemic regulation and local regulation
What is meant by systemic regulation of blood redistribution
Start of exercise there is increase in sympathetic outflow to heart and systemic resistance vessels
What receptors are involved in systemic regulation of blood redistribution
ADRENORECEPTORS
- Alpha constrict vessels in gut and cause skin vasoconstriction
- Beta 1 increase rate and force of myocardial contraction of the heart
- Beta 2 relax muscles and increase ventilation and oxygen uptake, cause vasodilation of blood vessels in skeletal muscles
What is role of endothelial/ myogenic mechanisms in local regulation of blood redistribution
NO relaxes smooth muscle cells leading to vasodilation
What tissue factors are released from contracting muscles (5)
Adenosine Inorganic phosphates CO2 H+ K+
How does total peripheral resistance change during exercise
Decreases by a third
How does MAP change during exercise
Only slight increase
How does systolic pressure change during exercise
Increased force of ventricular contraction (increased SV) causes increased systolic pressure
How does (can) diastolic pressure change during exercise
Decreases in total peripheral resistance can lead to decrease in diastolic pressure
What is pulmonary ventilation
a) at rest
b) in heavy exercise
a) 8l/min
b) 100l/min
How is rise is pulmonary ventilation achieved
Rise in respiratory rate and tidal volume
What is the pulmonary ventilation like during moderate exercise
Steady state ventilation directly proportional to work done
What is pulmonary ventilation like during heavy exercise
Ventilation is disproportionately large in relation to oxygen uptake
How do blood gases change during exercise
Pa02 decline slightly
PvCO2 rises
Pv02 rises
Effect of changing blood gases
Increase in gradient driving oxygen diffusion
What changes that happen during exercise shift the oxygen dissassociation curve to the right
- Increased CO2
- Increased H+
- Increase in local tissue temperature
Why does the body build up an oxygen defecit at the beginning of exercise
Because oxygen doesn’t immediately rise quickly enough to meet requirements
Why do athletes continue breathing quickly after exercise
To eliminate the oxygen debt
How long after exercise is finished does oxygen consumption reach resting levels
up to 60 minutes
What happens to creatine phosphate and ATP during initial phase of oxygen decline
They are resynthesised via oxidative pathways
What happens to excess lactate during oxygen decline
Resynthesised into glucose and glycogen
What is the role of central command system in terms of regulating cardiovascular response to exercise
Modulates baroreceptor reflex sensitity
Receives feedback from increased activity from afferent nerves from exercising limbs
What do metaboreceptors respond to
Changes in metabolite concentrations (pH and K+ mainly)
What area of the cerebral cortext is thought to initiate ventilation increase
Premotor area
What do chemoreceptors detect
CO2 levels
What do peripheral chemoreceptors detect
plasma potassium concentrations