Jet Lag, Shift Work, and Sleep Deficits: An Expert’s Guide to Managing Time Shifts
June 10, 2009
Whenever my wife and I plan our vacations, we choose locations that are least disruptive to our sleep schedules. For example, if we had to choose between LA and Florida, all things being equal, we’d choose Florida, since New York and Florida share the same time zones. It’s bad enough dealing with airport security let alone two young boys and an infant while traveling. Adding sleep deprivation to this would just make our vacation more work than it’s worth.
But for those of you who travel on business, or work the night shift, an erratic sleep schedule can wreak havoc on your health. The following information is geared especially for those of you who face these challenges. With simple, easy to do, lifestyle and behavioral modifications, you can overcome many of the side effects of these time zone shifts, to sleep better so that you can work better.
What You Must Know About Sleep Cycles
Our sleep cycles are handled by our internal sleep clocks, called circadian rhythms. It’s synchronized to sunlight at 24 hours with two peaks of drowsiness and two peaks of wakefulness during the day. The maximum time of drowsiness occur between 3-5 AM and 3-5 PM. After these peaks, we have periods of maximum wakefulness. Light sensors in our eyes affect the level of melatonin, the major hormone that controls sleep. In sunlight, melatonin is suppressed, and in darkness, is elevated.
Before we had light bulbs or transcontinental flights, we generally slept when it was dark and woke up when it was light. In the modern world, these natural built-in sleep-wake rhythms are by definition disrupted, aggravating or leading to a multitude of health-related, and even life-threatening problems. In the old days, sailors took weeks to months to cross the oceans, and had time to slowly adjust. These days, you’re lucky if you can get half a day to cope with these time shifts.
Jet lag is a phenomenon where you quickly change time zones either East or West, and your sleep rhythm is confused due to these sudden changes. Let’s take flying from New York to Los Angeles as an example. You’re flying back three time zones, so your body thinks it’s 9 PM New York time, whereas your visual cues in LA tell you it’s 6PM. Your body thinks it’s close to bedtime, but you can manage to stay up a few more hours, until you can get to bed.
However, if you fly from LA to NY, the reverse situation holds true. You have to go to bed a lot earlier, and that’s much harder to do. The simplest way of handling these situations is to plan ahead and to "practice" sleeping earlier or later depending on where you’re headed.
For example, if you’re flying west from NY to LA, a few days before your trip, go to bed later on a gradual basis and wake up later (if possible) the same amount to maintain the same total sleep time. You don’t have to go to bed 3 hours earlier, but even 1-2 hours should be better than nothing. On long flights you can’t do very much, and anything over 1-2 hours is probably not too productive. Once you’ve accommodated to your new location, you can do the reverse before coming back. In general, it takes about one day to adjust to one time zone change.
Other actions to combat jet lag is to avoid alcohol just before and during the flight. Alcohol is dehydrating and given the extremely dry conditions inside modern airplanes, any degree of sleep deprivation is aggravated. Alcohol also can cause sleep deprivation by causing breathing problems while sleeping due to its’ muscle relaxation properties. Exercising regularly before, during and after your trip will help to keep up your energy. Make sure to exercise outdoors early in the morning to reset your sleep clock.
While on the plane, try to get as much sleep as possible. Try to elevate your feet and walk around a lot on the plane. Bring lots of bottled water and stay hydrated. Exercise and stretch your muscles. Take a shower during layovers, if possible.
Some physicians have suggested eating a high carbohydrate, low protein meal for dinner, since carbohydrates contain precursors to serotonin, a neurotransmitter that’s known to regulate sleep. For breakfast, eat the reverse: a low carbohydrate and high protein meal. It’s also important to avoid eating or drinking alcohol at least 3-4 hours before bedtime (see accompanying article on travel).
There are some reports of people taking a variety of natural supplements to help them fall asleep such as valerian, melatonin, tryptophan, and l-theanine. Different people have different results from each of these ingredients so the only way to know whether or not they will work to to try them.
Lastly, bright light therapy in the early morning can help to awaken your sleep clock, especially if your new location is hours ahead of your old location (LA to NY).
I still vividly remember the month I was working in my ER rotation during my surgical internship. I was on rotating 8 hour shifts, which lasted one week at a time. After completing one 10PM to 6AM shift, as I was driving home, I nodded off and had to swerve suddenly to avoid hitting an oncoming car at 50 miles per hour. I’d been used to regular shifts where I went 36 to 40 hours being on-call for my regular surgical rotations, but this was the first time I had ever experienced a rotating shift. I almost died that morning.
There are over 20 million "shift workers" that work overnight in various rotating or steady shifts. Manufacturing companies, transportation, law enforcement, health industries and now many consumer oriented businesses such as restaurants, grocery stores and coffee shops all involve shift workers. Shift work not only includes 8 hours shifts on a rotating basis, but also includes 12 nightly shifts, not on a rotation schedule. Anyone who works outside of the typical 9 to 5 hours is considered a shift worker.
There are tomes of studies that show how detrimental shift work is not only in terms of employees’ health, but also in terms of accidents, many of them leading to fatalities. Even if someone works a regular nighttime shift, because there’s no visual cues from sunlight, there are health consequences as well. There have been many reports of increased rates of cancer, depression, and heart disease in shift workers. Even with newly installed bright lights in working environments, there are still residual health effects that can be measured, in addition to stresses caused by lack of social interaction and missing family gatherings or events.
As a result, nighttime workers continue to be more fatigued than their daytime counterparts, leading to more health problems and more accidents, despite all the new knowledge and added technology. According the National Sleep Foundation’s 2005 annual poll, shift workers were more likely to suffer from insomnia and excessive daytime sleepiness than their counterparts (61% vs. 47%, and 30% vs. 18%, respectively).
Shift workers’ main complaint is usually excessive sleepiness. They may also complain of insomnia, reduced performance, relationship difficulties and irritability/mood disorders (from the National Sleep Foundation).
Unfortunately, the only cure for this condition is to stop working shifts at night. For the 14% of the American population, this is not always feasible. However, there are recommended ways to cope with shift work, including avoiding long commutes or extended hours, and taking short naps and breaks throughout the shift. Engaging in teamwork, physical activity during breaks, and participating in support groups are other ways to keep alert while on the job. There’s currently a movement to make shift work environments nap friendly.
Steps to take for the shift worker to achieve sleep better during the day include: wearing dark glasses on the way home, keeping the same sleep schedules, even on the weekends, eliminating noise and light from the bedroom, and avoiding alcohol and caffeinated beverages before bedtime.
Don’t Sleep In On The Weekends
If you’ve ever gone out Friday night and came home late, it’s common practice for you to sleep in a few hours longer (unless you have young children). This is also what happens to many of you that work late during the week, catching up on your sleep on weekends by sleeping in a few hours longer. You may feel better after your extended sleep, but what you’ve done is the same thing as crossing a few time zones. Later in the evening, you won’t feel as sleepy or tired and will go to bed later, waking up later on Sunday. Monday morning, you have to wake up early again, and not surprisingly, you have a hard time getting up. You’ve now crossed back to your normal time zone.
In our modern society, it’s very easy to go to bed and wake up at erratic hours. With the advent of modern transportation, the light bulb, and the electronic media, it’s rare the someone will go to bed and wake up at the same time every day (I know that there are a few exceptions). Rather than sleeping in, it’s better to wake up at the same time in the morning as for a weekday, and go out and exercise in the morning sunlight. This will help reset your sleep clock. If you’re sleepy or tired later in the afternoon, take a short 30 minute nap. This is a much healthier way of "catching up" as opposed to sleeping in.
Putting It Together
If you also have an underlying sleep-breathing problem (most modern humans to various degrees), and you add either jet lag, shift work or erratic sleep schedules, then your sleep deprivation problems are compounded. Eating late because you came home late or just flew into LA from NY can prevent achieving deep, efficient sleep. Drinking alcohol also causes tongue muscle relaxation leading to more frequent obstructions and arousals, in addition to dehydration, only adding further to sleep debt. Poor quality or quantity sleep due to any reason over the long term can lead to increased appetite and weight gain. Weight gain narrows the throat, aggravating the problem even further. It’s not surprising that people who travel a lot for work frequently gain weight.
In our over-worked, over-stressed modern society, sleep is the first thing that’s sacrificed when we don’t have enough time. As I’ve alluded to in my book, Sleep, Interrupted: A physician reveals the #1 reason why so many of us are sick and tired, poor quality sleep can heighten your nervous system, making you feel even more stressed. Stress makes you more hungry for comfort foods, and the added weight can eventually narrow your throat, aggravating any underlying sleep-breathing problems. Knowing what we now know about the importance of good quality sleep, we should all strive to optimize the way we all sleep.
In Korean culture, it’s common for relatives and even strangers to ask, "Did you eat?" as a form of greeting. This originates from a long period in Korean history when they were either occupied or at war with another country and food was scarce. Lately, in our home, it’s become routine for us to ask, "How did you sleep?" Sleep has become so scarce in our modern culture, I wouldn’t be surprised if everyone else is doing the same before long.