# Equations

## Q = HR x SV

Cardiac output (Q) is the product of heart rate (HR) and stroke volume (SV). Heart rate is the number of heart beats per minute and is measured with the unit bpm. Age-predicted max heart rate is calculated by subtracting the person's age from 220. Stroke volume is the amount of blood that the heart pumps out with every beat. Stroke volume can be measured using either mL/beat or L/beat, but cardiac output is always recorded in L/min.

### Example:

A 30 year old man is exercising on a rowing machine at 80% of his age-predicted maximum heart rate. What is his cardiac output if his stroke volume is 120 mL/beat?

## F = ma(cosΘ)

Force (F) is the product of mass (m), acceleration (a), and the cosine of . Force is recorded in Newtons (N), which is equivalent to

### Work = F x Displacement

**Power = Work/Time = Force x Velocity**

Power:

Work: force exerted on a object and the distance the object moves in the direction of the force