Exercise Physiology Flashcards
Oxygen consumption
Resting level of oxygen consumption:
SV, HR and breathing rate is low at rest
0-5:
Oxygen deficit - started activity
More oxygen required by working muscles that can be supplied until HR and BP catch up with initial start of activity
Connections between aerobic and aneorobic exercise
Onset
02 consumption rises exponentially for the first few minutes
Fast component of exercise 02 consumption
Plateau
Attained at 3-4 minutes
Continued exercise: stable, steady state
Remain stable for duration of effort
Balance between energy required and ATP produced by a aerobic metabolism
No blood lactate accumulates
What is the consequence of continued exercise
Fluid loss
Electrolyte depletion
Glycogen store depletion
Elite athletes
High capacity of central circulation to deliver oxygen to active muscles
High capacity of active muscles to use o2
What does pericardium limit?
Maximal oxygen consumption by limiting stroke volume and cardiac output during maximal response
What is maximal oxygen consumption limited by?
Oxygen transport capacity of the cardiovascular system
Define oxygen deficit
Difference between oxygen consumption during exercise and total that would have been consumed had steady rate O2 consumption had been achieved from start
What is the immediate source of energy
Anaeorbic glycolysis
Hydrolysis of high-energy phosphate ATP and PcR
What is recovery
How long it takes to return to pre-exercise oxygen consumption
Higher intensity of exercise produce more anaerobic energy transfer
Higher blood lactate
Higher BT
Light exercise
Aerobic
Rapid attainment if steady rate oxygen consumption
Moderate-intense exercise
More anaerobic energy transfer
Longer time to achieve steady-rate oxygen consumption
Larger oxygen debt
Recovery takes longer
What is fatigue?
Depletion of all ATP
Myoglobin has lost all O2
Glucose and glycogen depleted
High accumulated levels of lactic acid
What is EPOC
Breathing fast and deep following exercise to increase the amount of oxygen in the body to return the body to its pre-exercise state
O2 deficit
How much of your effort was aneorbic
Steady-state oxygen consumption
volume of oxygen consumed whilst exercising/during the event
Fast component of EPOC
What happens after 2-3 minutes after event
Uses additional 1-4 litres of oxygen
Resynthesise all ATP and PC
Replenish all myoglobin with oxygen
Synthesise 50% of PC stores within first 30 seconds
Slow component of EPOC
Removal of lactic acid
Maintenance of ventilation, circulation and body temperature
Require 5-8L of oxygen
Why does temperature take time to recover post exercise?
Higher temperature - more chemical reaction
More oxygen consumed
What does recovery depend on?
Activity:
Type,
Duration of exercise
What is VO2 max?
Maximum volume of oxygen used/ utilised by the muscles per minute
Measured in: ml/min/kg
Factors affecting VO2max?
Cardiac hypertrophy - Increase stroke volume and cardiac output
Increased haemoglobin levels
Increased capillary density
High percentage of slow twitch muscle fibres
Factors affecting V02 max
Age - decline from 25 years (1% per year) - lost elasticity of heart - less diffusion of oxygen into lungs and muscles
Gender: males higher than females (higher body fat and smaller lung volume)
Fitness
Genetics
Node of exercise
Assessment of VO2 max
Activate body’s large muscle groups
Incremental exercise test
Workload increases until exhaustion
expired air samples collected in last min of exercise and analysed for oxygen and carbon dioxide
Limitation: motivation
What are the 3 systems that max oxygen consumption depend on?
Respiratory
Circulatory
Muscular
Lactate threshold
Intensity of exercise at which lactate begins to accumulate in the blood at a faster rate than it can be removed
What is the causes of BLA?
Low tissue oxygen Low blood oxygen Low blood flow to skeletal muscle Decreased redox potential Reliance on glycolysis Activation of fast twitch muscle fibres (type IIb) Reduced lactate removal Imbalance between production and removal
What are the symptoms of acute motion sickness?
Fatigue Nausea Decreased appetite Laboured breathing Tachycardia Nerve dysfunction
Acute motion sickness
Increase ventilator drive due to decreased O2 causes respiratory alkalosis
What is acclimitaztion?
Aim is to restore normal acid-base balance for adequate oxygenation
What are the components of acclimitaztion?
Kidneys: excrete base HCO3- and conserve acid
Increased capillaries in tissue: reduced distance for oxygen diffusion
More mitochondria and oxidative enzymes: use oxygen more efficiently
Increased red blood cell production
Increased 2,3-BPG synthesis - increase oxygen unloading at tissues
Increased lung volume
