Transcript Heart Rate, Blood Pressure, and Exercise

Heart Rate,
Blood Pressure, and
Exercise
Blood Pressure
• Made up of two numbers:
– systolic blood pressure
– diastolic blood pressure.
• Written as:
Systolic/Diastolic
• Spoken as:
Systolic Over Diastolic
• Measured in mmHg
Measuring Blood Pressure
• Sphygmomanometer and
stethoscope
• Normally, inflate cuff to 180 mmHg
–Allow pressure to drop at a rate of 3
mmHg/second
• Three Conditions
–No Flow
–Turbulent Flow
–Laminar Flow
Cardiac Output and Exercise
Q = HR x SV
• Q is cardiac output (L/min)
•HR is heart rate (beats/min)
• SV is stroke volume (ml/beat)
• Cardiac output must increase in exercise to
meet the metabolic demand of the active
tissues.
Total Peripheral Resistance
• Describes the resistance in vessels
• Change it via physiological response or by
physical measures
• Vasoconstrict or Vasodilate in response to
exercise.
– Active Skeletal muscles: Vasodilate
– Non essential organs &
Non-active skeletal muscles: Vasoconstrict
Systolic Blood Pressure
• Refers to the arterial pressure during the
contraction phase of the heart
• Corresponds with the onset of turbulent
flow through the arteries
• Pressure at first Korotkoff sound (a
beating sound with each heart beat)
• Average value is around 120 mmHg
• Reflects Cardiac Output, but is not equal
to it
Diastolic Blood Pressure
• Refers to the arterial pressure during the
relaxation phase of the heart
• Corresponds with the onset of laminar flow
through the arteries
• Pressure at last Korotkoff sound (a beating
sound with each heart beat)
• Average value is around 80 mmHg
• Reflects total peripheral resistance, but is
not equal to it
Blood Pressure Must Be
Regulated
• Low Blood Pressure
Blood will not reach all
tissues
Specifically those
where gravity is acting
against flow
Most importantly the
brain
• High Blood Pressure
– Heart is placed under
great stress
– Excess plasma
leakage
– At the extreme,
capillaries burst
Rate Pressure Product
RPP = HR x Systolic BP / 100
• Has no units
• An estimation of the total work of the heart
• Also known as the double product
Two Types of Exercise
• Dynamic
– Involves repetitive motions
– What we typically think of as exercise
• Static
– A held position with little or not muscle
movement
– Still requires energy
What happens during exercise?
• Exercising tissues require an increase in
blood flow
• Cardiac output (Q) must increase
• Cardiac output = heart rate (HR) x stroke
volume (SV)
Q = HR x SV
But how does that affect blood
pressure?
MAP = Q x TPR
Mean Arterial Pressure (MAP)
Cardiac Output (Q)
Total Peripheral Resistance (TPR)
MAP = Diastolic +1/3 (systolic-diastolic)
Effects of Exercise on Blood
Pressure
• Dynamic Exercise
–
–
–
–
Need increased Q
Increased HR
Decreased TPR
Diastolic BP stays ~
the same
– Systolic BP increases
and then levels off or
slightly decreases
• Static Exercise
–
–
–
–
–
Need increased Q
Increased HR
Increased TPR
Increased MAP
Increased DBP/SBP