Thanks ICT_SLB for the link. A most interesting coverage of the modern airliner's cabin air circulation and recirculation. We TPs rarely get involved in that stuff although I am now left wondering and wanting to know the extent of the thrust which must be lost for a typical engine installation with all of that air being bled from the engine compressor. The article mentions that occasionally pilots may shut down the air bleeds during take off for operational reasons.
During the tests on the Comet 2c before it went into RAF service I was tasked to run one on the ground for an hour or so whilst the boffins over pressurised the cabin to 23.7 psi or +9 on 14.7. They had strain gauges on selected areas of the fuselage.
I expected some physiological effects but didn't detect anything unusual.