Heart Rate Monitoring
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Transcript of Heart Rate Monitoring
Heart Rate Monitoring
INSY 3021
Auburn UniversitySpring 2007
Functioning
Blood Pressure
Pressure = Blood Flow (Q) x Resistance (P)
Controlling Factors (For Arterial Pressure) Pumping Action of Heart Blood Volume Elasticity of Arterial Walls Blood Viscosity Peripheral Resistance
Cardiac Output
Q = HR x SV(L*/min) (beats/min) (L*/beat)*- ml. also commonly used
Stroke Volume (SV)
SV = Quantity of blood pumped with each beat of the heart (ml/beat)
Factors affecting SV Venous return to heart Distensibility of ventricles Force of contraction of the ventricles in
relation to the pressure in the artery (Aorta or Pulmonary artery)
Sympathetic and hormonal stimulation
Heart Rate (HR)
HR = Heart Beats/min Most commonly studied circulatory
parameter Factors affecting HR
Sympathetic and parasympathetic stimulation of sino-artial (SA) node of the heart
Hormonal stimulation Temperature Age
Task Design and Analysis
What is the maximum load that must be supported?
Design within the acceptable limits of safety!
Estimator- HR Tests
Concept: Estimate MAC from simple tests How accomplished
Have person perform 1 or 2 standard workloads (usually step tests)
Measure HR response Compare results to known values for the
workloads Comments
Simple to perform- little stress Not exact- Good for screening Not as much equipment is required
Assessment of Task Strain
Percent Work Capacity Heart Rate (HR) Analysis
HR Analysis
Maximum HR (ACSM) = 220 – Age
Heart Strain = (Task HR / 220–Age) x 100% (Note: Should be < 65%)
Heart Strain = (Task HR – Resting
HR) / (220–Age–Resting HR) x 100% (Note: Should be < 50%)
Ability to Work Long Durations
Workers will “self pace” at 33 to 44% of VO2 Max for 8 hour shifts
Common task and design criteria is 33% of VO2 Max with HR of 105-115 Beats/min
Work-Rest Cycles
Work–Rest Cycles
Heart rate for a lifting task with 2 minute rest periods.
Must be able to determine if this type of job is acceptable and for whom.
Questions & Comments