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ECG and Blood Pressure Control
Transcript of ECG and Blood Pressure Control
Dr Alan Richardson
Plaque build up around the vascular walls
Become rigid – reduced distensibility and contractility.
Endothelial function – Reduced nitric oxide release.
All increase total peripheral resistance (TPR)
Blood Flow = Δpressure / resistance
Vasoconstriction: radius of the vessel decreases, decreasing blood flow
Vasodilation: radius of the vessel increases, increasing blood flow
Increased Haemoglobin Mass
Increased Red Blood Cell Count
Slower Blood Movement
Total Peripheral Resistance
(Related to Venous return)
Smaller muscle mass of upper body (localised blood flow)
Change in breathing patterns = changes in intrathoracic pressure
Muscle mass constricts vessels increasing TPR
Due to pooling of blood in visceral organs or lower limbs and post exercise vasodilation.
Supports use of exercise as a non-pharmacological treatment for hypertension
BP decreases after submaximal exercise to less than
pre-exercise values for both normotensive and
If resting = 120mmHg, post exercise will be ~110mmHg and
stabilises at 120mmHg after 12 hours
Consider the changes in blood pressure for both aerobic and resistance activity.
What are the key differences? What mechanisms cause the changes?......
Aerobic: High systolic, small change in diastolic.
Resistance: Large increase in both values
Aerobic: Large cardiac output = Increased systolic,
Minor vasoconstriction with ex induced sympathetic neural tone, although muscles release some vasodilators – so diastolic relatively unchanged
Localised blood flow
Upper body work induces greater BP due to smaller muscle mass of upper body
and the need to stabilise the body.
Breathing patterns are altered increasing the intrathoracic pressure (valsalva maneuver)
= Increased TPR.
What factors influence each of these?
Acid–base (pH) balance
Localised Blood Flow
Stimuli to increase local blood flow
increased oxygen demand
increases in metabolic by-products
Endothelium released factors
Endothelium-derived hyperpolarization factors (EDHF)
Read about cardiac morphology
Consider what morphological changes you would undergo in your sport.
What negatives are their to cardiac morphology?
We will be discussing next week
Neural Stimulation of the Cardiac
A 54yr old gentlemen has a stroke volume of 49ml/bt and an end systolic volume of 53ml. What is the gentlemen’s ejection fraction?
At maximal exercise his EDV can reach 131ml and his ESV can reach 43ml. What is his maximal predicted cardiac output?
SV = EDV – ESV
49ml/bt = ? – 53ml
EDV = 102ml
EJ = (SV / EDV) *100
EJ = (49 / 102) *100
EJ = 48%
SV = EDV – ESV
88ml/bt = 131 - 43
SV * HR (220 - age) = Q
2. 88ml/bt * 166bt/min = 14.6L/min
Premature Ventricular Complex