A definition of sleep.SLEEP

We sometimes think we are ill or depressed, when we are actually just tired from lack of sleep.

  • Maintain regular sleep patterns
  • Avoid caffeine, alcohol, nicotine and soft drinks
  • Keep sleeping room dark, cool and quiet









  • Body temperature is probably the most evident indicator of the circadian rhythm. Every 24 hours it has a peak and a low. This change is over only a one-degree Celsius range, but that is enough to have a significant effect on behavior.
  • Body temperature drops significantly around 11 pm to 12 midnight and is at its lowest sometime between 2 am and 5 am. When body temperature is at its lowest, we are least alert and most prone to sleep.
  • When shift workers reach this low, they tend to have the following three behaviors:
    • Uncontrollable urge to go to sleep
    • Seeing things out of the corner of one’s eye that aren’t really there
    • Night Shift Paralysis (a totally incapacitating paralysis that may be related to sleep paralysis and contributes to impaired levels of safety)
  • From approximately 6 am to 6:30 am the body temperature begins to rise, reaching its peak around noon to 1 pm. We usually feel most alert when body temperature is rising and reaches its 24-hour peak.
  • At around 2 pm to 5 pm the body temperature dips slightly, often called the “post lunch dip”.  Since the body temperature drops here, this can be a good time for the shift worker to try to sleep.  At approximately 8 pm the body temperature starts to rise again until about 10 pm. After this the body temperature begins to decline, the cycle repeats itself.
  • The circadian body temperature cycle is a physiological function of our body that serves to keep us awake during the day and signals us to sleep at night. When you are trying to sleep during the day after a night at work, your body temperature is rising and telling you to wake up. When you are trying to stay awake at night, your body temperature is falling and telling you that you should be sleepy.
  • Another cycle that is more of a factor at night is the digestive cycle. Rate of digestion and use of calories is highest in the morning and afternoon. Our body was not designed for high night-time food intake because digestion slows down.


  • Alertness varies throughout the circadian cycle in response to these biological changes. Yet there are other factors that affect our level of alertness:
    • The amount of sleep we have had previously
    • Our sleep bank balance
    • Our interest in what we are doing
    • The amount of muscular activity we are engaged in
    • Our ingested nutrients and chemicals
    • Environment light
    • Temperature
    • Sound
    • Aroma
  • All of these factors work together to allow a person to sleep. It’s important that a shift worker understands the pattern of sleep and the effects that shift work has on sleep, since many of the other effects of shif twork are strongly related to the changes in sleep resulting from shift work. 
  • The problem for shift workers is that their internal body rhythms do not always match the demands of their work schedule.  People who work shifts during the evening hours or overnight find themselves in the predicament of fighting against these natural body tendencies, or circadian rhythms.  When a person works a night shift it results in a sudden change in when he or she sleeps which is like flying to Europe.  This is why it gets the name “blue-collar jet lag”.
  • Shift workers who much sleep during the day usually find that:
    • They don’t get as much sleep or as refreshing a sleep as those of us who get the majority of our sleep at night
    • They spend more time in light sleep and do not get sufficient amounts of REM and deep sleep to feel emotionally and physically refreshed
    • Their circadian rhythms tend to be flattened out so they don’t have the normal physiological variation
  • The following link speaks more to the circadian rhythm and the potential health risks associated with shift work:  http://www.m.webmd.com/sleep-disorders/features/shift-work


  • Your body works on a biological 24-hour clock, with systems that become more active in the day and less active at night
  • Be aware of your body’s lows and highs
  • You can have an influence over your body’s natural tendency to sleep in a number of ways: getting adequate rest, exercising, eating right, adjusting your environment and being interested in what you’re doing
  • By understanding the five sleep stages, you can ensure you won’t be missing REM sleep, the part that keeps you emotionally refreshed
  • Human beings are very flexible and can often overcome natural physiological needs and behaviors.


  • Shift workers often must sleep during some daylight hours.  This already tough adjustment is made even harder by usually unnoticed commonplace noise, such as phones, lawnmowers and traffic, which are very disruptive for those seeking quiet.
  • There is also a certain amount of guilt and tension associated with this routine.  Since workers’ family and friends are usually up during the day and early evening, they often feel compelled to sacrifice sleep in order to socialize and feel part of a normal routine.  They may also engage in fragmented sleep and rely on naps to fill in the gaps, while attempting to maintain a traditional lifestyle.
  • On average, shift workers generally get 1.5 to 2 hours less sleep than the average person, and the sleep that they do get is often fragmented and disrupted.  The vast majority of workers need at least six hours of sleep.
  • Everyone has a specific daily sleep requirement.  If it is not obtained, sleep debt can occur.  As sleep debt increases, so does the tendency to fall asleep.  Because sleep debt can build gradually, people often do not realize the impact until it suddenly descends upon them.
  • The tiredness is then often blamed on illness, depression, stress, aging, etc., instead of simple lack of adequate sleep.  The problem can be further compounded by the unique lifestyle of shift workers.  Alcohol, which some rely on as a sleep aid, actually suppresses REM sleep.  Caffeine causes the sleep stages to cycle more rapidly than normal, thereby reducing the actual time spent in the critical Stage 2 and REM sleep which results in restful sleep.
  • While all body functions are affected by sleep deprivation, mood and cognitive abilities are often hardest hit.  This loss of cognitive ability, coupled with decreased motor skills can easily lead to an increase in accidents and injuries on-the-job.
  • Use the following suggestions to get an adequate amount of sleep:
    • Keep your sleeping room cool, dark and quiet – humidity, sunlight and noise are the great enemies of sleep.  Keep the temperature around 68 degrees F.  Sunlight is very significant because it is a major factor in keeping us on our day schedule.  Make sure all lights are screened out.  Insulate your bedroom with heavy drapes and carpets.  Also screen out all distractions and phone calls.  Use foam ear plugs and muffle noise with a fan or a “white noise” machine. 
    • Whenever your bedtime, day or night, a pre-bed meal should consist of foods that can help promote sleep – complex carbohydrates (pastas, potatoes, breads) and food rich tryptophan (fowl, legumes).  Avoid large meals within three hours of bedtime.
    • Give yourself time to unwind before bedtime, especially after a hectic day
    • Hire a babysitter during sleep times to protect against interruptions from your children
    • Experiment with different periods of sleep to see which works best for you.  For example, try taking advantage of the natural tendency to be sleepy in mid-afternoon.
  • Switching back to days
    • You shouldn’t try to change your biological clock when working nights because the nightshift lasts only a few days.  Try to maintain your daytime circadian rhythm by napping or sleep for a few hours during your usual sleep period if possible. 
    • When switching back to days after the night shift, it’s best to get most of your sleep the following night.  Sleep just a couple of hours shortly after night shift to shake off sleepiness.  Then stay awake all day and go to sleep at your usual bedtime at night.

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