Problem Set 1 Solutions

# The heart rate of a well trained athlete might rise

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Unformatted text preview: rate of a well-trained athlete might rise from 60 beats/min to 105 beats/min and the mean arterial pressure can rise from 100 to 130 mm Hg. The heart rate of a sedentar y person can rise from 72 to 125 beats/min and the mean arterial pressure can rise from 100 to 150 mmHg. Determine the volume of blood ejected during each heartbeat (stroke volume) and the peripheral resistance for an athlete and a sedentary person. Assess the power of the left side of the heart for the athlete and the sedentary person. where P is power, is the mean arterial pressure, V is the ventricular volume, W is work, and f is the heart rate in beats/sec. Make sure that your units are consistent! (Note: 1 mmHg = 133.3 Pa, and 1Pa =1N/m2 ). Solution where CO is the cardiac output (L/min), SV is the stroke volume (L) and HR is the heart rate (beats/min). CO is 5 L/min at rest and 25 L/min at exercise. Athlete At rest: At exercise: Sedentary person: At rest: At exercise: Resting Heart Rate (beats/min) Exercise Heart Rate (beats/min) Resting Mean Arterial Pressure (mm Hg) Exercise Mean Arterial Pressure (mm Hg) Stroke Volume at Rest (L) Stroke Volume at Exercise (L) Peripheral Resistance at Rest (mm Hg/L /min) Peripheral Resistance at Exercise (mm Hg/L/ min) 60 72 105 125 100 100 130 150 0.0833 0.0694 0.238 0.2 20 20 5.2 6 Athlete Sedentary person Athlete At rest: At exercise: Sedentary person: At rest: At exercise: To calculate work and power, we can assume that the mean arterial pressure is constant and where is the stroke volume. Athlete At rest: At exercise: Sedentary Person: At rest: At exercise: Athlete Sedentary person Work at Rest (Nm) 1.11 0.925 Work at Exercise (Nm) 4.12 4.0 Power at Rest (J/s) 1.11 0.924 Power at Exercise (J/s) 7.21 8.33...
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