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Sleep Disorders

Overnight shift, when is best time for sleep

05/31/2007

Question:

I am just started working full time overnight, 10pm -6am. Part of the plan is to have more time with my school-aged children. I usually go to sleep around 9 am after everyone hsa left and get up by 3pm to get ready for dinner and such. I may or may not take a nap inbetween then and 10pm. Most people that work overnight seem to stay up during the day after work and instead go to bed around 3 or 4 and sleep then, they say it is better to sleep altogether and go to work after getting up to feel more refreshed. The overnight shift is going to be a regular part of my life for sometime, I want to get myself on a regular sleeping pattern so my body can adjust and I can plan amy time accordingly. With all these factors in mind, which is better day, afternoon, or a little of both?

Answer:

Shift work is quite common in modern society due to the 24/7 nature of world. As a result, about 20% of the population is involved in some form of shift work and about 15% of these individuals will have problems with sleep.

The body’s circadian rhythms usually cycle over a 24 to 25 hour time period. These rhythms are reset daily to match a 24 hour day by factors such as exposure to daylight and social cues, for example when we eat our meals. The internal clock can be advanced (moved forward so you are sleepy earlier in the evening) or delayed (moved backwards so you are more awake late into the night) by changing the timing of light exposure and other social cues (such as when we eat our meals). However, the internal clock can only be adjusted by 1-2 hours in either direction per day with these maneuvers. When individuals try to alter their rhythms by more than this, they tend to feel poorly with fatigue, sleepiness and nausea (as seen with Jet Lag, for example). Furthermore, it often takes several days to fully adjust our circadian rhythms to a new schedule and thus going back and forth between schedules over the course of a few days can be difficult and almost guarantees problems.

There a couple of major sleep issues with shift work schedules. First, as you point in your plans for your sleep, shift workers tend not to get enough sleep. Due to the fact that they are sleeping off-cycle from their normal internal rhythm, coupled with interruptions and social pressures to be awake during the daytime, shift workers tend to short themselves by 1-2 hours per day of needed sleep. This can have long-term consequences on health and well-being. Second, while it would be ideal to be able to totally invert your circadian cycle (sleepy during the day and awake at night), most shift workers are unable to do this despite best efforts. Thus, many shift workers do not to feel optimal as a result of the mismatch between their internal clock and their need to be awake at night.

It’s not clear if sleeping during the morning into the afternoon is better or worse than sleeping in the afternoon into the evening. Sleeping in the late afternoon may make more sense as there is a natural dip in the circadian cycle at that time that usually makes us a little sleepy. However, most shift workers are unable to sleep during late afternoons due to social pressures. For some, sleeping in two 4 hour blocks seems to help them get the sleep they need.

Having noted the above, if you must work a night shift, there are some things that you can try that may help. The following is a list of recommendations for shift workers:

1) Try to maintain a regular shift and not rotating shifts. Regular shifts lead to more regular sleep times which may help you get more sleep.

2) If you have to rotate shifts, move with the clock. For example, it’s better to rotate days to evenings to night than to go in reverse order. This is because it’s easier for our internal clocks to make our days longer rather than shorter.

3) Try to keep your sleep schedule close in time on days you work and days off. Some individuals also find it easier to work shifts on consecutive days as opposed to having intermittent days off.

4) Scheduled napping when at work may help. This should occur during “low points” in the circadian cycle, namely between 0300-0500 and mid afternoon. Naps should be short (< 30 minutes) to avoid grogginess that comes from getting into deep sleep.

5) Timing of light exposure is important. If working at night, the environment should be as brightly lit as possible, especially early in the shift. Avoid bright light in the several hours before bedtime, including on the drive home (wear sunglasses!).

6) Careful use of caffeine may be helpful. Caffeine containing beverages are best when used early in night shift and avoided in the 6 hours before bedtime.

7) Prescription stimulants or sedatives may provide benefit to some individuals. Consultation with a physician is needed before considering these options.

8) For chronic night shift workers, melatonin supplements may be helpful to take before bedtime. Consultation with a physician is advised before pursuing this.

If you would like further information about shift work, circadian rhythms, sleep disorders or sleep itself, I recommend the American Academy of Sleep Medicine website. In addition to information about sleep medicine, the website also contains a list of accredited Sleep Centers and may help you to locate one nearest you. The website Sleep Education.com also has plenty of consumer friendly information about sleep. Good Luck!

Related Resources:

Sleep Tips for Shift Workers

For more information:

Go to the Sleep Disorders health topic, where you can:

Response by:

Dennis   Auckley, MD Dennis Auckley, MD
Associate Professor of Medicine
School of Medicine
Case Western Reserve University