I wasn't sure where to ask this, but at its core it's a workplace issue more than anything else.
I'm in university studying medicine, and fairly soon I have to go through a bunch of internships that include working very long shifts (most people I've asked have had to do shifts of around 20 hours, and some horror stories say up to 40 hours). Everyone I've talked to said refusing is not an option, basically you have to do it or you're fired.
As someone who has a hard time sleeping and who doesn't have much innate endurance for long hours, what techniques can I use to survive this?
Apart from that, I really enjoy medicine, so I don't want to drop out and work in something else. I'm a very fast learner, so I get over the academic requirements with almost no exertion. I love the material and I'm passionate about many medical specialties, mostly ones that in themselves don't have extra long working hours, so after the internships and medical residency the problem should go away.
Edit 1: I'm in Canada. I'm not sure what the legislation is, apparently the university says the maximum is 16 consecutive hours, but this is routinely ignored by bosses and attempts at contestation seem very dangerous, career-wise.
Edit 2: I do realize many internships and hospitals will not be like that, but it seems almost everyone has to go through it at some point. My main goal is minimizing the physiological and psychological damage to my person and the risk of making medical mistakes.