Exercise Physiology Flashcards
What produces more energy by weight, CHO oxidations or FFA oxidation?
CHO oxidation
Is it to easier change from slow to fast twitch fibres or vice versa?
Vice versa
Why are older people more likely to be affected by hyperthermia?
They have a depressed CV system therefore are less able to utilise the blood circulation to remove heat
What is VO2 max?
The maximum rate of O2 consumption possible being exertion.
Usually expressed as L/min or mL/(kg.min)
How is blood volume maintained during exercise?
Intracellular and interstitial water is shunted into the plasma circulation
How does mitochondrial fat oxidation change in response to exercise?
It increases
How does distribution of CO to skin change in response to increase intensity of exercise?
It increases by up to 4 fold before reducing at near maximal intensity
By what degree can CO increase in response to exercise in normal individuals?
Up to 5-fold increase
What is a greater determinant of VO2 max, oxygen delivery to muscles or oxygen consumption by muscles?
O2 delivery
Which cancers are most affected by physical inactivity?
Colon
Breast
What is the equation for VO2?
CO * (CaO2 - CvO2)
What is the major mechanism of heat loss in swimmers?
Conduction
Define fatigue
The inability to produce the required amount of force or power output
Why is the creation of an exercise mimicing pill so difficult?
Because of 50% of the protective of effect of exercise is understood
What is functional sympatholysis?
This is where locally produced factors desensitise sympathetic NS signalling to sympathetic vasoconstrictor effects in order to prevent them causing vasoconstriction while the muscle has a high O2 demand
What is fat max?
The level of exercise intensity at which the most fat is burnt?
At what level of intensity is fat max reached during intense exercise?
55% of Wmax
How is the proportion of one’s muscles which are type I fibres collerated to one body fat percentage?
The more type I fibres, the less body fat
How does O2 uptake change in response to increasingly powerful activity output?
It increases to an upper limit
What drives the initial hyperapnea in response to exercise?
Higher corticol control
Muscle afferents
What is hyperaemia?
Increase in blood supply to tissues
What is the pattern of recruitment of different muscle fibre types over the course of a contraction?
Slow twitch > Type IIa > Type IIb
How does GLUT4 expression change in response to exercise?
It increases
What is the metabolic equilivant of task (MET)?
The ratio of energy consumption for metabolic activity during exercise vs at rest.
It is used as a measure of fitness
What is the major source of energy during endurance exercise at 75% Wmax?
Muscle glycogen
What drives hyperapnea in high intensity exercise?
High H+, lactate, K+
High temperature and catecholamines
Which increases more in response to exercise, diastolic or systolic BP?
Systolic
Diastolic doesn’t change significantly
What produces more energy by weight, CHO oxidation or glycolysis metabolism?
Glycolysis
What has more capacity as a fuel source, FFA or CHOs?
FFAs
What is the main reason why athletes have a greater VO2 max cf to untrained people?
They have a greater capacity to increase their CO
Are genetics a more important deterrminant of success for sprinters or long distance runners?
Sprinters
Why do highly trained cyclists sometimes get haemodilution?
They get an increase in blood volume without an accompanying increase in RBCs
How does the muscle’s microvasculature change in response to exercise?
Increase capillary density
Increase capillary recruitment
Build up of which compounds in muscle contributes to its fatigue?
ADP
Mg
Pi
What causes cardiovascular drift?
Hyperthermia
Dehydration
Increase plasma [adrenaline]
Displacement of blood to the peripheral circulation
Do men or women burn relatively more fat?
Women
What is the another name for type I muscle fibres?
Slow twitch muscle fibres
What causes the decreased hyperventilation in trained individuals?
Reduced blood lactate/H+
Lower plasma K+
Lower plasma catecholamines
What type of muscle fibres have the least mitochondria?
Type IIb
What is the mechanism by which blood flow to muscle is increased in response to exercise?
Metabolic vasodilators are released by contracting myocytes, endothelials and RBCs
Muscle pump redistributes blood
How can amphetamines be used to enhance performance?
They block the perception of fatigue
How is it possible that MAP and HR can increase stimultaneously during exercise?
THe baroreceptor threshold is increased
What is VO2?
The rate of oxygen consumed by tissue per an amount of time
Usually measured as L/min or mL/(kg.min)
What is IMP?
A break down product of ADP
What causes the increase in CO in response to training?
Increased blood volume
Increase in Frank-Starling mechanism
Increased heart size
Increase LV chamber size and mass
Increased adrenergic sensitivity
What are the major fuel sources during a 10s sprint
Glycolysis
Phosphocreatine
ATP
How does carbohydrate use by mitochondria change in response to training?
Decreased carbohydrate usage
What are the two molecular targets of exercise pills?
PPARdelta
AMPK
What is cardiovascular drift?
The increase in HR and decrease in SV that occurs in response to prolonged exercise
How do you differentiate fatigue from muscle weakness?
Muscle weakness occurs at rest
