I’ve worked some challenging jobs in my career. One such job taught me how long I can go without sleep and still function, to a point. Long hours, presentations, meetings, followed by taxi, bus, and train journeys to the next destination and hotel, then repeat. High stress and anxiety meant that with each hotel stay sleep rarely came, or when it did it wasn’t deep enough.
After the first day I can function at about 60%. After the second it’s 40%. By the morning after the third sleepless night I’m at 20%. I can function, I can get through meetings and presentations, but anything not scripted and my brain is sluggish. I Don’t drink caffeine or other stimulants so I’m running on energy and sheer willpower alone. I Don’t drive on day three. It’s too dangerous.
By the end of day three I’m a zombie and I will sleep for around 10-12 hours. The next day I’m at around 80%. It generally takes about two days to catch up and get back to normal.
This is not a long-term strategy for dealing with stressful situations. If I can, I generally avoid them. But if not I know I can function without sleep, but only for three days.