NAPPING

(and Sleep Inertia )

Healthy from the Start Resources for Shiftworkers

Napping is an effective strategy for shiftworkers to combat fatigue and increase their total daily sleep. Short naps (10-20 minutes) can boost alertness in the short-term, while longer naps (90 minutes or more) provide longer lasting benefits. Be aware of sleep inertia though, the grogginess experienced after waking from a nap.

For shiftworkers, achieving the recommended 7-9 hours of sleep each day can be challenging, with many not meeting this goal (2,3). Napping is a valuable tool to supplement sleep and reduce fatigue, with two effective napping strategies to consider:

Short Naps: Aim for a quick 10-20 minute nap for an immediate energy boost.

Long Naps: Use 90-minute naps for long lasting benefits to your alertness and performance. 


For quality napping, choose a cool, dark, and quiet environment. If you're not at home, find a similar setting to optimise your rest. If you’re napping at work, make sure this is safe and appropriate, and you’re keeping sleep inertia in mind. Read more about creating the perfect sleep environment here.

Try to avoid naps of intermediate lengths (i.e., 20-90 minutes) to minimise waking up during deep sleep (Stage 3 sleep), which can lead to sleep inertia.

Note that deep sleep and sleep inertia can be associated with any nap length, including naps as short as 10 minutes (83).

On top of how long your nap lasts, it’s also important to consider the time of day when you’re napping. Avoid napping too close to your main sleep, particularly if you’re having a longer nap (i.e., 90 minutes or more). Napping in the hours leading up to your main sleep period can lower your sleep pressure, meaning it’ll be harder for you to fall asleep and stay asleep when it’s bedtime. You might also notice differences if you nap during the day compared to overnight. If you’re on a part of your roster when you’re able to maintain a traditional sleep/wake schedule (i.e., awake during the day and sleeping at night), a daytime nap can boost alertness and reduce feelings of fatigue. However, your body is primed to be awake during these hours, so it might be trickier to fall asleep during the day.

On the other hand, if you’re on night shift, and you’re able to get a nap in overnight, it’s important to remember that your body is primed to be asleep during this time. That means that you may be able to fall asleep easier, but the nap you take may be harder to wake up from, and could increase your chances of experiencing sleep inertia.

“ When I started in shiftwork, I used to avoid napping as much as possible, because I’d read somewhere that it was bad for your sleep later on. I only recently learned that information like that is usually not designed for shiftworkers, and we need to have a different approach to napping. Now I use naps before work or on my days off to lower my fatigue and boost how much sleep I’m able to get.”

- Micah, 27, experienced shiftworker.

SLEEP INERTIA

Sleep inertia is a common experience among shiftworkers, characterised by post-sleep grogginess and decreased performance (83). It's more likely to occur when you wake from deep sleep (Stage 3 sleep). Sleep inertia can also be worse after sleep loss (i.e., not getting enough sleep in the past day or week), after staying awake for too long, or after waking up during your circadian low (84). Effects typically last from 15 minutes to an hour, during which time the risk of accidents and errors is increased (84).

To minimise sleep inertia, stick to either brief naps (10-20 minutes) or a full sleep cycle (approximately 90 minutes).

If grogginess hits after waking, try these strategies:

Caffeine Nap (also known as a nappuccino):

  • Consume caffeine right before a short nap. When you wake up, the caffeine should start taking effect, reducing sleep inertia (85,86). You then have the alerting benefits of both sleep and caffeine.

Bright Light:

  • Exposure to bright light upon waking can help to make you feel and perform better (87,88).

Physical Activity:

  • Engaging in a quick, energising activity can boost alertness (84,89). Read more about the benefit of activity for shiftworkers, including improving sleep and managing fatigue, here.

It’s important to note that these strategies may only provide some improvement to your alertness or performance.

Even though you might feel more alert after a nap, you might not be aware of performance impairments (90).

It’s best to wait at least 15 minutes after waking from any sleep period before doing safety critical activities (e.g., driving a car, operating machinery).