Question

Miguel is a 25-year-old jogger with a target heart rate of 125 bpm. His resting pulse is 70 bpm. His blood volume is approximately 6.8 litres. At rest, his cardiac output is 6.3 litres/minute and his EDV is 150 ml. What is his stroke volume at rest?

Answer 1

`0.09 ("Liters")/("beat")" at rest"`

Explanation:

The equation that is going to be helpful for us is the following:

`color(white)(aaaaaaaaaaaaaaa)color(blue)(CO = HR * SV)`

Where:

`"CO=cardiac output: volume of blood the hearts pumps out"`
`color(white)(aaaaaa)"every minute (mL/min)"`

`"HR=heart rate:the number of beats per minute (beats/min)"`

`"SV= stroke volume:volume of blood pumped out by the"`
`color(white)(aaaaaa)"heart in 1 beat (Liters/beat)"`

`---------------------`

Isolate the unknown, plug in and solve.

Given

`"CO" = 6.3 "Liters"/("min")color(white)(---)"HR" = 70 "beats"/("min")`

• `color(blue)(CO = HR * SV)`
  `color(white)(--)`
• `(CO)/(HR) = SV`
  `color(white)(--)`
• `(6.3 "Liters"/cancel(min))/(70 "beats"/cancelmin) = "SV" = 0.09 ("Liters")/("beat")`

`color(orange)("Answer": "SV"= 0.09 ("Liters")/("beat")" at rest")`