1Two things going on inside you
Muscles make a leftover, breathing carries it away
When cells use oxygen to release energy from fuel, they make carbon dioxide. Breathing supplies oxygen and removes carbon dioxide. This model follows just the carbon-dioxide balance; keep breathing normally while you use it.
Muscles burn fuel
Working muscles need more energy. Using oxygen to release energy from fuel produces more carbon dioxide, which blood carries to the lungs.
Breathing does two jobs
In and out. Fresh air in, used air out. Breathe faster and the used air leaves faster.
2Resting body vs sprinting body
Same lungs, very different amount of leftover
Here are the two bodies side by side. Look how much used air each one is making — that is the one difference this model follows.
Resting: muscles barely burn, so used air is just a slow trickle. The model starts with production and removal balanced.
Sprinting: muscles burn hard, so used air comes in a flood. We will test a different breathing setting after your prediction.
3Your turn — set the effort
Push the effort and watch the body keep up
Drag the runner from a stroll to a sprint. Watch the muscle burn brighter, the used air pour out faster — and breathing rate change alongside it.
4Now try to break it
What if breathing stays slow? 🔒
Keep breathing normally yourself. In this screen model, set effort to 80% while removal stays at its resting rate. Predict the tank level after six model seconds, then compare faster removal.
Guess before you find out
The model starts at 10 units. At 80% effort with slow removal, where will its carbon-dioxide tank end?
First test: 80% effort, slow removal. The tank is a teaching diagram, not a blood measurement.
Keep the same effort and try faster removal. Predict what happens to the tank before running it.