What a Medical Resident Learns About Sleep (While Being Chronically Sleep-Deprived)
Dr. Amara Nwosu is a second-year internal medicine resident at a Level I trauma center. She answered seven questions about what sleep deprivation actually feels like from the inside — and what studying sleep medicine taught her that she couldn't have learned any other way.
Dr. Amara Nwosu completed her internal medicine internship year at 58 average weekly hours of scheduled work, with call nights extending to 28-hour shifts. In her second year, she began a research rotation in sleep medicine. This conversation happened on a Tuesday morning, three days after her last overnight call.
You’re now studying sleep medicine while working a schedule that most sleep researchers would describe as chronically sleep-restricting. What’s that like?
It’s genuinely strange. You sit in rounds discussing the cognitive effects of sleeping six hours a night for two weeks — the attentional failures, the decision-making impairment — and you are that person. You’re the data point. I looked up the Van Dongen study on our training — the one where subjects on six hours a night for two weeks showed performance equivalent to total sleep deprivation — and I calculated that I’d been living approximately that study for the previous fourteen months.
The most disorienting part is that you don’t feel as impaired as the tests say you are. Sleep-deprived people are genuinely bad at assessing their own impairment. I know this from the research, and I still felt like I was fine, mostly. The insidious thing is that “mostly fine” and “significantly cognitively impaired” overlap more than you’d expect.
What did you get wrong about sleep before this rotation?
I thought fatigue was a continuous variable — that you could feel yourself getting more impaired as sleep debt accumulated, the way you feel yourself getting more full as you eat. It’s not. Your subjective alertness and your objective performance diverge surprisingly quickly.
There’s a specific phenomenon in the literature called “state instability” — where you have these brief episodes of lapses in attention (microsleep events, essentially, even while apparently awake) that you don’t experience consciously. You think you read the chart. Your eyes moved across it. You registered almost nothing. I probably had this happening in ways I’ll never know.
The other thing I got wrong: the recovery timeline. I assumed that a good weekend would reset a bad week. The data doesn’t support that, especially with chronic exposure. You can narrow the deficit, but the full neurological picture — receptor sensitivity, inflammatory markers, some of the structural stuff — takes longer than two days.
What did sleep deprivation actually do to your judgment, that you noticed?
The most consistent thing was emotional flattening. Not anger, not irritability particularly — just a reduced range of affect that made some clinical conversations harder. A family in crisis at 3 AM when you’ve been awake for twenty-two hours: you know you’re supposed to be bringing full presence to that conversation, and you’re doing a functional approximation of it. It bothered me when I thought about it later.
Cognitively, the things that went first were novel reasoning and working memory — specifically, holding multiple facts simultaneously and drawing inferences. The things that held up were procedural skills and tasks I’d done many times. Routine procedures under sleep deprivation were surprisingly preserved; novel clinical presentations were harder in ways I couldn’t always identify in the moment.
Is there anything about sleep science that the clinical environment ignores?
The individual variation is enormous and almost entirely unaddressed. The range in how people tolerate sleep restriction is genuinely wide — there are people who function reasonably well on six hours for a week, and people who are significantly impaired after two nights of restricted sleep. The schedule is identical for both. The exposure is identical. The impairment is not.
There’s some genetic work on this — specifically the DEC2 gene variant that seems to allow some people to function better on less sleep, and the BHLHE41 variant, which has been studied at UC San Francisco by Ying-Hui Fu’s lab. It’s not actionable yet in a clinical sense, but it explains why the person next to you on call seems fine and you feel like you’re dissolving.
The current system treats sleep restriction as a uniform exposure and doesn’t adapt the schedule. That’s partly logistical, but it’s also partly that the research hasn’t translated into policy yet.
What worked for you on call nights specifically?
Two things with real effect. One was a 15-minute nap in the first half of the night if there was a window — specifically 15 minutes, with an alarm, no exceptions. Sara Mednick’s work on ultra-short naps is right: 15 minutes gives you alertness benefits without significant sleep inertia. I tried longer naps early in residency and woke up worse than before. The length matters.
The other was temperature. ICU floors are cold, which is actually good — I’d find a chair in a warm on-call room and fall asleep faster and more deeply than the person who was comfortable the whole night. That sounds small but cumulatively it added up.
What do you wish patients understood about sleep deprivation?
That its effects are almost invisible to the person experiencing them. This is the clinically important part. Patients in hospital environments are often sleep-deprived for reasons beyond their control — fragmented sleep, noise, early morning rounds, anxiety — and they’re making decisions about their care in that state. The consent process, the preference conversations, the end-of-life discussions — these happen in conditions that impair the very cognition needed to make them well.
We don’t really have a solution for that, but I’d want people to know: if you’re making a significant health decision while you’re in a hospital and you’ve been sleeping in three-hour chunks for four days, consider asking if you can delay a non-urgent decision until you’ve had a real night of sleep. You’re allowed to do that.
Is there anything the research got wrong — something you’ve observed doesn’t work the way the literature predicts?
The caffeine timing research is right in theory but much harder to apply in practice than it looks on paper. The guidance is: don’t caffeine within 6 hours of sleep, because of the half-life effect. In residency, that means stopping caffeine at 9 PM on a night call that starts at midnight. The optimal caffeine window and the window in which caffeine is most needed are almost always the same window.
What I’ve found practically — and this isn’t in the literature, it’s just pattern recognition from residency — is that caffeine used strategically during the last 4 hours of a call to cover a specific high-demand period, accepted as a known sleep disruption trade, sometimes beats the alternative of being impaired during that window and then sleeping poorly anyway. I’m not advocating late caffeine. I’m saying the optimization problem is different in the real clinical environment from how it appears in a controlled sleep study, and residents are making that calculation constantly.
An aside on accountability in high-constraint environments: Dr. Nwosu uses a group text with her co-residents to confirm when everyone made it home safely after overnight calls. “It’s accountability for basic safety, not waking up,” she said. “But the psychology is similar — you feel you owe something to the people who check on you. It changes the behavior slightly.” DontSnooze operates on a similar principle for morning commitments; the specific application is different.
FAQ
What does chronic sleep deprivation do to cognitive performance? Chronic sleep deprivation produces impairment across multiple cognitive domains, with the most consistent effects on sustained attention, working memory, and novel reasoning. The critical finding from research by Hans Van Dongen at Washington State University is that people significantly underestimate their own impairment — subjective alertness diverges from objective performance after several days of restriction, making self-monitoring unreliable. Procedural and routine skills tend to be more preserved than novel problem-solving under sleep restriction.
How do medical residents cope with sleep deprivation? The most evidence-backed strategies used in high-demand clinical environments are strategic ultra-short naps (10–15 minutes, with alarms to prevent deeper sleep onset), consistent bedtime discipline on post-call nights, and caffeine timing calibrated to specific high-demand windows. Anecdotally, environmental temperature and social accountability — knowing colleagues are monitoring your safety — also play a role. Full recovery from intern-year-level sleep restriction takes longer than most residents expect.
What is state instability in sleep deprivation? State instability refers to the fluctuating attentional state that characterizes moderate to severe sleep deprivation, characterized by brief involuntary lapses in attention (essentially microsleep events) that occur without the person being aware of them. The subjective experience is of sustained attention; the objective record shows gaps. Research by Hans Van Dongen and David Dinges at the University of Pennsylvania has documented state instability as a core feature of chronic sleep restriction.
Can you function well on 6 hours of sleep if you’re used to it? The perception that you can function normally on 6 hours after adapting to it is not supported by performance data. Van Dongen’s study (2003) found that subjects on 6 hours per night for two weeks showed performance declines equivalent to total sleep deprivation — but reported only feeling slightly sleepy. There is genuine genetic variation in sleep need (DEC2, BHLHE41 variants studied at UC San Francisco by Ying-Hui Fu), but true short sleepers who function fully on 6 hours are rare — estimated at less than 1% of the population.