488-Metabolic Equations

Vocabulary flashcards covering VO2 concepts,METs, and common conversions from the metabolic equations lecture.

VO2

Rate of oxygen consumption, usually reported as ml·kg⁻¹·min⁻¹ (relative) or L·min⁻¹ (absolute); VO2 can be expressed as VO2 = H + V + R.

Gross VO2

Total VO2 during activity, including resting metabolism.

Net VO2

VO2 required for exercise only; gross VO2 minus resting VO2.

Absolute VO2

VO2 expressed in L·min⁻¹ or mL·min⁻¹ (not normalized to body mass).

Relative VO2

VO2 expressed per unit body mass, in mL·kg⁻¹·min⁻¹, used to compare individuals.

MET

Metabolic equivalent; 1 MET = 3.5 mL O2·kg⁻¹·min⁻¹ (resting).

Resting VO2

VO2 at rest, typically about 3.5 mL·kg⁻¹·min⁻¹.

3.5 ml/kg/min

Value of 1 MET; the resting oxygen cost used in VO2 calculations.

H component

Horizontal VO2 cost: energy cost of moving forward (speed-related).

V component

Vertical VO2 cost: energy cost of vertical movement (grade).

R component

Resting VO2 component included in VO2 = H + V + R.

VO2 = H + V + R

Structure of VO2 equations showing horizontal, vertical, and resting contributions.

Walking VO2 equation

VO2 ≈ 0.1 × speed + 1.8 × speed × grade + 3.5 (speed in m/min; grade as decimal).

Running VO2 equation

VO2 ≈ 0.2 × speed + 0.9 × speed × grade + 3.5 (speed in m/min; grade as decimal).

Leg ergometry VO2

VO2 ≈ 10.8 × W × M⁻¹ + 7 (or VO2 ≈ 1.8 × (work rate)/M + 7); W = external work rate (kg·m/min); M = body mass (kg).

Arm ergometry VO2

VO2 ≈ 18 × W × M⁻¹ + 3.5 (or VO2 ≈ 3 × (work rate)/M + 3.5); for upper-body cycling.

Stepping VO2

Oxygen cost of stepping; depends on stepping rate (12–30 steps/min) and step height (0.04–0.4 m).

Monark ergometer

A brand of cycle ergometer used to measure VO2; distance per revolution

kg·m·min⁻¹

Unit of work rate; product of mass (kg) and distance (m) per minute.

1 mph = 26.8 m/min

Speed conversion factor used to convert mph to meters per minute.

1 inch = 2.54 cm

Length conversion factor from inches to centimeters.

1 Watt = 6 kg·m/min

Work rate conversion used in ergometry calculations.

1 L O2 = 5 kcal

Energy expenditure equivalence: one liter of oxygen consumed yields about 5 kilocalories.

3500 kcal per lb fat

Energy content of adipose tissue: ~3500 kcal per pound of fat.

lb to kg conversion

Mass in kg = weight in lb ÷ 2.2 (approx).