The respiratory quotient is the true stoichiometric ratio of CO2 produced to O2 consumed when a fuel is oxidised:
- Carbohydrate (glucose): C6H12O6 + 6 O2 → 6 CO2 + 6 H2O → RQ = 6/6 = 1.00
- Fat (palmitic acid): C16H32O2 + 23 O2 → 16 CO2 + 16 H2O → RQ = 16/23 ≈ 0.707
- Protein (mixed amino acid oxidation): RQ ≈ 0.80
The canvas spawns individual O2 and CO2 flow particles on a cadence derived from these true molecular ratios — the displayed RQ is measured each second from the actual particle counts, not read off a lookup table. Energy expenditure uses the abbreviated Weir equation, EE(kcal/day) = 1440 × (3.941·VO2 + 1.106·VCO2), which converts the measured gas exchange directly into a calorie burn rate.