because apparently we humans are all differently efficient in converting calories into watts.
We’re not that different though. It doesn’t vary that much between people. It’s pretty universally 20-25% of energy gets converted into mechanical energy, with the other 75-80% lost as heat.
What does differ is how mechanically efficient the bike is. A commercial gym stationary bike might only be 80% efficient at converting the energy put into the pedal down into the flywheel, and that is what gets read by the power meter. A high end race bike is above 95%.
Due to the roughly 25% efficiency, the math of kilojoules to calories burned is almost exactly 1:1.
Outside of a clinical lab where you get hooked up to a machine that reads the actual CO2 from your breath as you exercise, a power meter is the most accurate you’re going to get though.
We’re not that different though. It doesn’t vary that much between people. It’s pretty universally 20-25% of energy gets converted into mechanical energy, with the other 75-80% lost as heat.
What does differ is how mechanically efficient the bike is. A commercial gym stationary bike might only be 80% efficient at converting the energy put into the pedal down into the flywheel, and that is what gets read by the power meter. A high end race bike is above 95%.
Due to the roughly 25% efficiency, the math of kilojoules to calories burned is almost exactly 1:1.
Outside of a clinical lab where you get hooked up to a machine that reads the actual CO2 from your breath as you exercise, a power meter is the most accurate you’re going to get though.