PSYC06 - Lectures 3 & 4, Chapter 12, Blascovich et al., 2004 – Cardiovascular System
Heart rate (bpm) and heart period (ibi) – The frequency with which your heart beats
Measurement – There are two methods of quantifying heart rate: beats per minute
(bpm) and interbeat interval (IBI or RR Interval). BPM is the count of heartbeats (R-
spikes) within a minute (~70 for men, ~75 for women). IBI is the time between each
beat (R-spike) in milliseconds (~860 for men, ~800 for women). So in one you
measure the number in a minute, and in the other you measure the time inbetween
Psychological correlates/meaning – An increased HR means stress, motivating tasks
and excitement. While a decreased HR means an aversive stimuli.
Pre-Ejection Period (PEP) – The time between when the heart ventricles depolarize and
when blood is pushed out of the heart. It reflects the strength of heart contraction.
Measurement – It needs two physiological measures to extract PEP: ECG tells you
when the ventricles depolarize (O) and Impedance tells you when the ventricles eject
blood (B). PEP is measured in milliseconds.
Psychological correlates/meaning – It is the only pure measure of the sympathetic
nervous system activity. It is concomitant (associated) with engagement and approach
Relationship between heart rate and PEP – The lower the heart rate the higher the
PEP. The higher the HR the lower the PEP. They are inverses of each other.
Cardiac Output (CO) – The amount of blood pumped through the heart.
Measurement – There are two ways to measure: Stroke volume (SV) is the amount of
blood ejected from the heart on each beat, measured in millilitres (avg. ~70mL/beat),
Cardiac Output (CO) is the amount of blood ejected from the heart per minute,
measured in litres (avg. ~5 L/minute).
Psychological correlates/meaning – It is the key determinant of oxygen and glucose
available to the brain and muscles. The higher CO, the better mental and physical
Blood pressure (BP) – It is the pressure against the walls of your blood vessels.
Three measures of BP – Systolic Blood Pressure (SBP) is the pressure against vessel
walls when the heart is ejecting blood. Diasto