I used to do adventure races of 24 or 48 hour duration. can confirm that after 20+ hours of endurance you 100% start having microsleeps and hallucinations. 20 mins sleep is all you need to get going again for a few more hours.
The only marathon I ever did was cram for a couple finals and playing computer games between them and after. I was working on 72 hours when the blue on my monitor started to ripple and decided it was time to go to bed… almost an hour after it started.