Shift work disorder guideline offers cautious advice on light, caffeine and naps

What the researchers did

The American Academy of Sleep Medicine set up a task force of sleep and body-clock experts. They reviewed the research on treating shift work disorder in adults. This is the sleep problem that can affect people who work nights or other unusual hours.

They looked at three goals: less sleepiness at work, better sleep when sleep is disturbed, and helping the body clock adapt to night work. The evidence was graded using a standard method called GRADE. Most treatments were compared with no treatment.

A companion review in the same journal reports that the search found 3,045 articles. Of these, 118 studies had data that could be analysed. They included laboratory trials of simulated shift work and trials of real shift workers.

What they found

All 19 recommendations were "conditional", meaning they are suggestions for clinicians to weigh against each person's situation. None was "strong". For sleepiness during work, the only recommendation backed by moderate certainty evidence was a prescription medicine, modafinil or armodafinil, taken 30 to 60 minutes before the night shift. The task force also suggested bright light during the night shift, caffeine before or during the shift, and a nap before the night shift. Combining caffeine with light, or a nap with caffeine, was also suggested. They also suggested a clockwise rotating shift pattern over an anticlockwise one. They suggested eating a snack or nothing during the night shift, rather than a full meal.

For poor sleep after night shifts, the task force suggested CBT-I, a talking therapy for insomnia. They also suggested several medicines, including melatonin and some prescription sleep medicines. They suggested against older sleeping pills called benzodiazepines. For helping the body clock adapt to night work, they suggested bright light at night. They also suggested fixed daytime sleep times, and glasses that reduce morning light.

The task force did not favour 8-hour or 12-hour night shifts over the other. For most recommendations, the certainty of the evidence was very low or low.

The caveats

• Most recommendations rest on very low certainty evidence, so the true benefit of many of these steps is uncertain.
• Most treatments were compared with no treatment, not with each other, so the guideline cannot say which option works best.
• The guideline is for adults with shift work disorder. The task force notes that fully adapting the body clock is not a realistic goal for people on rotating or frequently changing shifts.
• The guideline did not look at shifts longer than 12 hours. Several authors declared links with industry, and some have ties to the academy that commissioned the work.

What this could mean for you

For people who work nights, this guideline suggests that timing matters. Caffeine is suggested before or during a shift, but the authors warn that caffeine close to bedtime can disrupt sleep. A nap before a night shift is suggested, but allow time for grogginess to pass before driving or other safety-critical tasks.

Bright light during the shift, regular daytime sleep times and CBT-I are non-drug options that the task force considered. The guideline also covers medicines, including melatonin. Anyone thinking about a medicine, or about changing what they take, should talk to their doctor first.

Because the evidence is weak, these are sensible things to discuss with a doctor or sleep clinic. They are not guaranteed fixes.