Maybe you’ve done this? I’ve worked nights to meet deadlines. Tenders, proposals, various targets, some unrealistic, some necessary, some not, night shifts due to short staffing, not to mention the rollercoaster of sleep that young children create. And if I’m honest, assignments from back in the day.
Now what? The deadline’s gone. The activation might be over. Everyone goes home, exhausted, sleeps for ten hours (or not!) and turns up the next day “fine”.
Lab studies from one long-running sleep programme show that one long night really, really, does not put people back where they started. Further, a weekend of catch-up sleep doesn’t reliably do it either, even if we kid ourselves that it does. That’s not news to anyone who’s worked through a big event. It’s still worth a reminder, because it changes how you plan the days after.
If you’re EM surge staff, with whom I’ve spent some time recently, you’ll know what I mean.
The one-night test
In a 2010 lab study at the University of Pennsylvania, healthy adults spent five nights with only four hours in bed, then got one recovery night of up to ten hours in bed. The ten-hour group actually slept about nine hours. (For context, the US sleep medicine societies recommend 7 or more hours a night for adults, and say more than 9 can be right for someone recovering from sleep debt.)
The next day, their lapses in attention and their ratings of how sleepy they felt were both still above where they’d started. Their attention was measured with a ten-minute reaction-time test. A lapse was a response taking half a second or longer. The ten-hour group averaged about three lapses per test before the short nights and about six the day after their long recovery night, so roughly twice as many. The spread around that average was wide.
In a 2024 study, the same lab ran the same five short nights and offered some people a recovery night of twelve hours in bed. Attention still wasn’t back to baseline the next day.
Five nights at four hours is a pretty hard deal. The 2010 researchers expect milder restriction to make recovery in a single night more likely. Still, nine hours of sleep didn’t undo five short nights.
Four nights of twelve hours?
So how many nights does it take? Short answer, nobody has worked that out yet.
A 2021 study used the same five nights at four hours and followed them with four nights in a row of twelve hours in bed. Reaction speed still hadn’t returned to baseline after the fourth night. That study had no comparison group of people who never lost sleep, so the authors can’t rule out the lab routine itself playing a part. That’s fair (and honest research).
A review co-written by Siobhan Banks, who led the 2010 study and co-led the 2024 one, puts it in a nutshell, concluding that recovery from a run of short sleep isn’t possible with one or two nights of extended sleep, and that weekend catch-up sleep doesn’t fully restore function or protect people when the short nights start again. The same review notes that no one has yet developed recommendations for how many days off are enough.
What comes back first
Not everything lags though.
After one long night in the 2010 study, people’s ability to stay awake in a dim, quiet room was close to their own baseline at eight hours in bed and back to it at ten. In the 2021 study, a symbol-coding task that measures speed of thinking showed no statistically significant impairment after the short nights and sat above baseline right through recovery, which the authors put partly down to practice.
Self-rated sleepiness is the awkward one. In the 2021 and 2024 studies, one long night brought people’s sleepiness ratings back to baseline while their attention stayed below it. In the 2010 study, neither had recovered after one night. So on Monday some people will rate themselves no sleepier than usual and mean it. What’s still lagging is the ability to keep responding quickly to something you’re watching for, which is what that ten-minute reaction time test measures.
The next run picks up where this one left off
The 2024 study’s main question was what happens when the short nights start again. After the first five short nights and one in-between night of anywhere from zero to twelve hours, people did another five nights at four hours. Their attention carried on roughly along the track it had been on in the first run. The in-between night made a small difference, and it faded quickly. The decline was slower second time around, so the second run didn’t hit harder than the first; people started it from where the first had left them.
The authors, drawing on earlier work, say one or two nights of catch-up sleep may be almost enough to recover temporarily, but a hidden vulnerability stays and shows up quickly when short sleep resumes. They list disaster response among the settings where runs of short sleep are broken by nights with even less sleep or none, though they didn’t study responders.
They also say people carrying this deficit may be impaired, possibly without knowing it, when driving or operating safety-sensitive equipment. That’s their extrapolation from lab tests, not something anyone measured on the road. Measuring it on the road would be sketchy, one feels.
One rough night in an otherwise well-slept stretch is a different matter. The same researchers suggest an occasional disrupted night may have relatively little impact in the long run. In the study itself, a night with no sleep after the five short nights still hit attention and sleepiness hard the next day.
What to plan after a surge, or similar
This is for CDEM controllers and council managers after an activation, and for any manager after a deadline push that cost people several short nights. Two things follow, which I’ve built from the research, rather than anything the researchers tested.
Plan several consecutive nights with long sleep opportunities, not one lie-in. In news that should surprise nobody, in the 2010 study, more time in bed on the recovery night brought more recovery overall, and the ten-hour group slept almost an hour longer than on their own ten-hour night before the short run. My version of that is no early briefings and no evening call-outs for the people who worked the surge, for several nights running, rather than a Saturday off and a full Monday.
If possible, don’t roster the same people straight into the next surge. In the 2024 study, people went into the second run from wherever the first had left them. So build the next shift from people who weren’t short of sleep the first time.
Where you can’t avoid using them, think about the drive home after a long shift and the jobs that are mostly watching and waiting, such as a river gauge, a radio channel or an incident dashboard. The researchers name driving and safety-sensitive equipment. I’d add monitoring, because it leans on the same sustained attention that reaction-time test measures. I expect vigilance to be affected and unreliable too.
As I said, this is my pitch, not the researchers’. None of these studies tested a recovery plan like this, and the research shows that one long night isn’t enough without yet saying how many are. So write the recovery nights into the stand-down plan before the stand-down, while the roster is still in your hands and before anyone starts rating themselves as no longer sleepy.
Photo by Kate Stone Matheson on Unsplash