CPETlab

Learn to read a cardiopulmonary exercise test.

CPETlab takes you from the physiology, on curves you can bend yourself, to real de-identified studies, to the thing the course is actually for: picking up an unfamiliar test and saying what it shows.

Every module is a hook question, a short idea, something to drive, and a handful of questions. Nothing is a video you sit through.

89modules
19section reviews
14real studies
4units
V̇CO₂ overtakes V̇O₂exercise →L/minV̇O₂V̇CO₂
Oxygen uptake and carbon dioxide output through one real ramp test. Where the blue line crosses the red, the body has started producing more CO₂ than it is taking up O₂ — and every module here is built on measurements like these, not on drawings.

How the course is divided

Four units, and the difference between them is what the data is — idealised, then real, then measured against a guideline, then handed to you cold.

Start anywhere, but the order is the argument. Unit 1 builds the physiology on clean curves, so that when Unit 2 puts a real breath file on the screen you already know what shape you expected. Unit 3 is where a measurement meets a line somebody drew. Unit 4 gives you the study and the referral question and nothing else.

Drive the nine panels yourself

The simulator is the engine the physiology unit is built on. Change a variable — stroke volume, dead space, the ventilatory set-point — and watch all nine panels answer at once. It is illustrative rather than measured, which is exactly what makes it safe to break.

What makes this different

Real data

Fourteen de-identified studies

Breath-by-breath files from real tests, carried through the whole course. You meet the same patients again and again, and they get harder to dismiss.

No typed numbers

Every figure is fitted at build time

The slopes, thresholds and percentages in the text are computed from the patient's own data when the module is built. The prose cannot drift away from the plot.

You measure it

Unit 4 hands you the workbench

Place the peak, the threshold, the fitting windows. Every number in your report comes from an anchor you put there, against limits computed for that patient.

Declining counts

"I cannot call this" is a right answer

Several studies here have landmarks that cannot honestly be read. Saying so is graded as correct — because producing a number anyway is the error the course is about.