Flashcards
Aerobic capacity
Cards in this deck (33)
- 1CARDIOVASCULAR RESPONSES TO ACUTE EXERCISE-
- 2RHRuntrained 60-80bpm
trained as low as 30-40bpm
anticipatory response - decreased vagal tone, increase in adrenaline and noradrenaline - 3HR during exercisedirectly proportional to exercise intensity
- 4HRmax220 - age
208 - (0.7 x age) - 5Steady-state HRplateau
optimal HR for meeting circulatory demands at given submaximal intensity - 6Stroke volumeincreases with intensity up to 40-60% VO2 max then plateaus
most training adaptations are in SV not HR
SV during max exercise = double standing SV
supine > standing SV - 7~ factors that increase SVFrank-Starling mechanism
increased EDV, increased stretch, increased contraction
noradrenaline and adrenaline increase contractility (increases ejection fraction)
decreased afterload (=tension during systole) - 8~ SV changes during exercisehigher preload at lower intensities >> increased SV
increase in HR decreases filling time, decrease in EDV and SV
decreased after load via vasodilation >> increased SV - 9Cardiac outputQ = HR X SV
increases with intensity, plateaus near VO2 max
resting 5L/min
untrained max 20L/min
trained 40L/min - 10Fick principleVO2 = Q x (a-v)O2 difference
- 11Blood pressuremean arterial pressure (MAP) increases during endurance exercise
- systolic BP increases in proportion to intensity
- diastolic BP slight decrease or increase at max - 12~ MAP= Q x total peripheral resistance
- 13Blood flow redistributionblood flow redirected to exercising muscle - greatest metabolic need
- 14~ vasoconstrictionsympathetic vasoconstriction shunts blood away from splanchnic circulation (liver, pancreas GI) and kidneys
- 15~ vasodilationlocal vasodilation increases blood flow to exercising muscle
- triggered by metabolic, endothelial products
sympathetic vasoconstriction in muscle offset by sympatholysis
skin vasodilation permits heat loss - 16Cardiovascular driftincreased core temperature and dehydration
HR drifts upwards to compensate downward drift in SV (increased skin blood flow, decreased plasma volume and venous return/ preload) - 17RESPIRATORY RESPONSES TO EXERCISE-
- 18Ventilationimmediate increase
- anticipatory response from central command
gradual second phase increase in ventilation
- chemical changes in arterial blood
- increased CO2 and H+ detected by chemoreceptors
- right atrial stretch receptors - 19~ low intensityincreased tidal volume
- 20~ high intensitybreathing rate also increased
- 21Dyspneashortness of breath
poor aerobic fitness
inability to adjust to high blood PCO2 and H+
fatigue in respiratory muscles due to increased ventilation - 22Hyperventilationexcessive ventilation
anticipation/ anxiety
increased PCO2 gradient between blood, alveoli - 23Ventilatory thresholdpoint where litres of air breathed in is greater than O2 consumed
associated with lactate threshold and increased PCO2
surrogate measure of lactate threshold? - 24Respiratory limitations?ventilation not normally a limiting factor
- respiratory muscle very fatigue resistant, account for just 10% of VO2 and 15% of Q during heavy exercise
BUT MAY BE LIMITING IN ELITE ATHLETES
- ventilation-perfusion mismatch, exercise-induced arterial hypoxemia (EIAH) (pulmonary gas exchange limitations)
airway resistance and gas diffusion also not normally limiting
restrictive/ obstructive respiratory disorders can be limiting - 25Acid-base balancemetabolic processes produce H+ >> lower pH, acidosis 6.6-6.9
controlling pH:
- increased ventilation helps H+ bind to bicarbonate
- chemical buffers (bicarbonate, phosphates, proteins, haemoglobin)
- kidneys excrete from buffers
- ACTIVE RECOVERY - 26ADAPTATIONS TO AEROBIC TRAINING-
- 27Cardiovascularincreased VO2 max
increased SV:
- heart mass and LV volume increased
>> increased plasma volume, EDV
- decreased HR
- LV mass increased, greater force of contraction
- decreased afterload - 28Respiratorypulmonary ventilation
- decreased at submax intensity
- increased at max intensity (increased tidal volume and respiratory frequency)
pulmonary diffusion
- increased at max due to increased lung perfusion
arterial-venous O2 difference
- increased due to increased O2 extraction due to increased oxidative capacity - 29Musclemitochondrial function
- increased size and number
oxidative enzymes (SDH, citrate synthase)
- increased activity
>> enhanced glycogen sparing - 30Metaboliclactate threshold increased
lower RER (higher dependency on fat) - 31HIGH VS LOW RESPONDERS-
- 32VO2 max response to endurance trainingexplained by ~30 gene RNA expression signature in muscle
explains 23% of gains in VO2 max - 33Solving problem of non-respondersmore potent training stimulus
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- MED213 Flashcards on Aerobic capacity, created by Emily H on 30/12/2021.
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- Emily H
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