Acute responses to exercise Flashcards
Ventilation
How much air is breathed in and out in one minute
Tidal Volume
Amount of air that moves in and out of the lungs with each respiratory cycle
Ventilation Formula
Tidal Volume x Respiratory Rate = V
V (L/min) = TV (L/breath) x RR (breaths/min)
Respiratory Rate
Number of breaths you take per minute
Ventilation during exercise
15-30 times greater than rest
Ventilation at low to moderate exercise intensity
Tidal volume and respiratory rate increase proportionally to increase ventilation
Ventilation at submaximal intensity
Ventilation increase rapidly then slows to plateau taking about 4-5 minutes
Ventilation at max intensity
Ventilation increases until exercise is stopped. Tidal volume plateaus and further increases in V are due to an increase in RR
Diffusion
Gas exchange occurs in the lungs at the alveolar-capillary interface and in the muscle of the tissue-capillary interface moves from high to low area of pressure
Diffusion in lungs
- O2 is high, goes from alveoli into bloodstream
- Co2 in blood high, goes from blood into alveoli
Diffusion in muscles
- Blood O2 levels high and muscle O2 are low, blood to muscle
Diffusion during exercise
Increased due to increased surface area of alveoli and muscle tissue
Cardiac Output
The amount of blood pumped out of the heart in one minute
Stroke Volume
The amount of blood ejected by the left ventricle per beat
Heart Rate
the number of times the heart beats per minutes
Cardiac Output Equation
Q(L/min) = HR(beats per/min) x SV(ml/per beat)
Cardiac Output when exercising
Increase in HR and SV
Cardiac Output in submaximal exercise
SV increase to max with any further increases in Q are a result of HR
Cardiovascular Responses: Blood pressure
- Increase in Q = an increase in blood pressure
- Arteries vasodilate(increase) = more blood draining from arterioles into capillaries
-Strength training = higher blood pressure but less HR a Q
Venous Return increased by what 3 mechanisms
- Muscle pump - muscle contractions
- Respiratory pump
- Vasoconstriction
Cardiovascular responses: Blood volume
- During exercise blood volume decreases by around 10%
- Plasma levels decrease in first 5 minutes then stabilise
Redistribution to Blood flow during exercise
- Away from spleen, kidney, gastrointestinal tract
- To working muscles
- Heart and blood flow maintained
- Blood supply to heart increase
- Blood flow to skin assists in regulation of body temperature HOWEVER during max this decreases
A-VO2 difference
Arteriovenous - oxygen difference: The difference in oxygen content between the arteriol blood and the venous blood. During exercise the working muscles extract greater amounts of O2 from the blood increasing AVO2 difference
Muscular responses: Motor unit recruitment
- Exercise= increase in amount of force developed in working muscle
- To do this more motor units need to be recruited
- Strength and speed dictate how many motor units are recruited
- Motor units will contract maximally or not at all
Adenosine Triphosphate (ATP)
A chemical compound made up of adenosine and three phosphates
Adenosine Diphosphate (ADP)
A chemical compound made up of adenosine and two phosphates
Phosphocreatine (PC)
A chemical fuel (also called creatine phosphate or CP) consisting of a bound phosphate and creatine molecule
Muscular responses: Energy substrates
- ATP immediate source of all muscular contractions
- Short supply so then muscles rely on energy substrates for fuel
- During exercise PC donates a phosphate to ADP to resynthesise ATP
- Exercise = decrease in fuel levels (ATP, PC, glycogen, intramuscular triglyceride concentration) within muscle
Muscular responses: Lactate
- At sub max exercise sharp increase in lactate – until O2 can meet demand of the muscle and lactate removed
- At greater intensities blood lactate levels increases beyond removal rate – Lactate Inflection Point
Lactate Inflection Point
The exercise intensity beyond which lactate production exceeds removal, sometimes referred to as the lactate threshold
Venous Return
The rate of blood flow back to the heart
What happens in redistribution of blood flow
Vasoconstriction of arterioles supplying inactive muscles and organs reduces blood flow here and vasodilation of arterioles supplying active muscles increases blood flow.
Why is there a redistribution of blood flow
To allow blood (oxygen and glucose) to be transported to the working muscles which have a high demand for energy
Diffusion
Where gases such as oxygen and carbon dioxide always move from areas of high pressure to areas of low pressure.
VO2 Max
The maximum amount of oxygen an individual can utilise during intense or maximal exercise.
How VO2 max assists performance
The greater your VO2 max, the more oxygen your body can consume and the more effectively your body can use that oxygen to generate the maximum amount of ATP energy.
Oxygen defict
The period of time when you start exercising in which the bodies oxygen demand exceed the supply from its systems.
Steady State
When oxygen supply equals oxygen demand
EPOC stands for
Excess Post Exercise Oxygen Consumption
Oxygen Debt or EPOC
The time in exercise where the athlete has more oxygen supply then the oxygen demand. Occurs in warm down, and assists in removal of metabolic byproducts
Oxygen debt two parts
- Restoring PC takes 2-3 minutes and 2-3 litres of oxygen is consumed
- Removal of lactic acid
