Exercise, breathing and oxygen debt sim
Set the load on an exercise bike, count the breaths and read the depth off a spirometer trace, read blood lactic acid, and plot breathing rate and lactic acid against time to see the oxygen debt being repaid after hard exercise.
Breathing and gas exchange; respiration · covers the IGCSE, O-Level, GCSE topic
What the sim shows
Model: one illustrative person, about 15. At rest about 14 breaths a minute, 0.5 L each (7 L a minute). Cycling makes breathing deeper and faster. Above about 110 W the muscles also respire anaerobically (glucose → lactic acid, much less energy), lactic acid builds up in the blood, and after stopping the breathing stays fast and deep for several minutes while the oxygen debt is repaid. Breathing rate = breaths in 30 s × 2. Values illustrative, from memory. Nothing moves on its own.
- The bike's load slider: drag it along the top tube to set the load (watts)
- Stopwatch, tally counter and lactate meter: tap them to count the breaths or read the blood lactic acid
Use it in your lessons
- Try it here: anyone can unlock 2 figures free, and a free account unlocks up to 5. Runs on a laptop, a Chromebook or a phone; nothing to install.
- Present it and share student links with the teacher plan, from US$5 a month, billed yearly.
- Put it on your own website or LMS for US$9, paid once, or every sim from US$29 a month.
Free guide: 12 practicals as sims, and how to run one in a lesson →
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