Last Updated on November 18, 2023 by pg@petergamma.org
If you are lucky you an find this «Treadmill for functional diagnostics for competitive athletes (1980)» for a good price on eBay:
https://en.wikipedia.org/wiki/Bruce_protocol
Eventually all protocols are open and you can anayse it with a TRS 80 and you can put the machine in your bed room. But we will wait until something more handy is available for home scientists.