amphet and coke increase endurance by shutting down the responses to the bodys warning signals of tiredness or pain – making it easy to overdo things and feel the consequences later.
Cocaine also has an analgesic (pain killing) effect which could account for your friend not noticing any aches and pains until later!
If its common after every weekend and starting to affect life during the wek I’d suggest calming things down for a bit – but on a positive note I don’t think any of this is permanent damage. I’m in my 30s now and can still go partying, do manual work such as DIY or working on sound and video equipment or ride my bicycle on 15-20 mile trips without any discomfort and I don’t consider myself to be “super-fit”!
