Mastering your circadian rhythm: sleep is vital to maintaining health and fitness on the night shift

Despite a lifelong commitment to physical fitness, I found my health and physique eroding after working long nights in an Intensive Care Unit. Fortunately, I was transferred to Sleep Medicine, where I discovered how to maintain health, musculature and well-being while working on the night shift. I applied what I learned, as a sleep technologist, to my health and fitness regimen and have been blown away by the results!

Let's face it, everyone working on the night shift has trouble staying fit. Working at night leads to sleep loss, which causes circadian rhythm disruption. The circadian rhythm, otherwise known as the "body clock," coordinates the metabolic demands of our daily wake/sleep cycle. When we are in the wake phase, we metabolize food faster to provide our bodies with energy in the form of calories. In the sleep phase, our digestive tract slows down, body temperature drops and mental alertness decreases.

When your circadian rhythm is disrupted, your body becomes stressed, causing loss of muscle tone and weight gain. However, you can stay fit on the night shift. The first step is understanding why the graveyard shift is so detrimental to your health and physique.

The main problem with night shift work is daytime sleep is shorter than nighttime sleep and frequently interrupted. Night workers usually nap, rather than sleep, during the day. They also suffer from chronic "jet lag" caused by repeated changes in their sleep habits. A report recently published in Sleep magazine concluded that long-term sleep deprivation may lead to sleep disorders that persist even after returning to a daytime job.

Sleep is not "down time," but rather an active and complex part of your daily life. There are at least rive stages of sleep. Each stage is essential for rest and hormonal releases that help build muscle and strengthen the immune system. However, simply falling asleep does not guarantee you will experience all stages of sleep.

The refreshing sleep you need requires good "sleep hygiene," a consistent pattern of sleep and wake times, as well as any routine that encourages sleep. By not maintaining a consistent sleep routine, you are robbing yourself of your body's natural healing abilities. Taking a long bath, reading or simply relaxing after your shift can increase your chances of sleeping well.

When you start to drift off, you enter stage one. In this stage, you are not aware you are sleeping. Lights and low-level noises are "tuned out," preparing you for the next stage of sleep. Stage one sleep can overtake an exhausted individual no matter how much he or she is trying to stay awake. Also, your eyes can be open during this stage, although you are not thinking about what you are seeing. Ominously, this stage is also called "driving" sleep, since you can easily slip into it when you are sleep deprived. Thus, it is often the culprit of car accidents caused by a "sleepy driver."

Stages two and three are progressively deeper levels of sleep. When awakened, you realize you were sleeping, but probably do hot recall dreaming. During these stages, melatonin is released, easing you into an even deeper sleep. Melatonin resets the body clock to synchronize metabolic functions with times of activity and rest. This hormone continues to be released over several hours. Therefore, a nice, long sleep lends itself to better sleep.

Stage four, also called "delta sleep," is a very deep sleep. During the first cycle of delta sleep, human growth hormone (HGH) is released. This hormone signals the body to repair worn tissues. Lack of delta sleep can be especially harmful to those who are training, since HGH helps restore muscles after a strenuous workout.

Lastly, Rapid Eye Movement (REM) is the stage in which you are most likely to remember dreaming. The longer you sleep, the longer each episode of REM becomes. REM is important because when your body lacks this type of sleep, you become forgetful and irritable. Unfortunately, over-the-counter sleep aids decrease the amount of REM you experience. Moreover, you may feel dazed the following day--even after the medication has worn off.

By following a few simple guidelines, you can maintain or even improve physical fitness on the night shift. These changes should allow you more time with your loved ones because you won't fall asleep on the sofa or be too tired to go out.

Guidelines For Better Sleep

Guideline 1

Sleep in the dark. If your bedroom is bright during the day, the use of blackout curtains is suggested. Plywood or heavy cardboard can also reduce the amount of daylight leakage. Cut the plywood or cardboard to size and place it in the window frame when it is time to sleep. If your bedroom cannot be darkened, use another room for sleeping.

Guideline 2

Keep it quiet. Use a fan or any white noise device that generates calming sounds. These devices help drown out daytime activity noises. Phone ringers should be turned off and the volume of answering machines should also be turned down. Keeping an ear out for the phone will cause you to sleep lightly and be awakened unnecessarily. A cell phone or pager number given only to your loved ones can help you sleep at ease. This allows your loved ones to reach you in an emergency, but to otherwise let you sleep.