What are larks and owls?
Many people will describe themselves as preferring to be awake and active in the morning (larks) or in the evening (owls). This is generally due to their underlying body rhythms (or circadian rhythms). This is controlled by chemicals and signals in the body that tell us it’s time to get up or time to go to bed. The most powerful signal the body can receive to distinguish night from day is light, especially light of the blue wavelength. In response, the body adjusts its temperature and amount of melatonin (sleep hormone) to help trigger wake and sleep. For example, if you are an evening person, and come home from work or school and use lots of afternoon or evening light (house lighting, computer, TV), you are more likely to go to bed later in the evening and want to get up later in the morning. However, if you get up early and go jogging while the sun is coming up (early morning light), then you are more likely to want to awaken early in the day and go to bed early in the evening.
So, what if you have the lights on when you get up and put light on when you come home at night? Which is more powerful? Just like other systems in the body, there are multiple controls for the time of sleep onset and the time of awakening. Interestingly, the time you awake is much more powerful for controlling the entire sleep-wake cycle then the time you go to bed. In other words, if you awaken at the same time every day (including weekends), you are more likely to maintain this time as the time you get up, no matter when you fall asleep. This is in fact, even hardwired into our genes. There are multiple genes that are thought to participate in the timing of sleep, one of them is even called “clock.”
Is it better to be a morning person or an evening person?
A few hours of earlier awakening or later awakening does not seem to affect the human body much. However, there has been much research done with shift workers and it has been found that overall people who work the night shift or rotating shifts do have more health problems than those who work daytime jobs. It is not clear if this is because of the reversal of their sleep-wake pattern fighting their underlying natural body rhythms (circadian rhythm) or if this is due to chronic sleep deprivation due to the inability to constantly adjust to different sleep and wake times.
What can I do if I must work nights?
If you must work nights, then you will need to sleep in the daytime. This will be exactly opposite not only of your own internal sleep-wake cycle but also opposite of external light-dark cues. If you have not worked nights before, or rarely work nights, it will benefit you to nap for a maximum of 30 min at 3 PM. This prophylactic nap will help to lessen the sleep debt or pressure from being awake since the morning. When you arrive at your shift, try to keep the ambient light between 2,000-5,000 lux or less than half of regular outdoor daylight (10,000 lux). It is okay to drink caffeine at the start of a shift, but caffeine should be avoided after 4 AM. A light snack at 12 midnight may also be helpful, but if you are planning to return to daytime shifts, you may wish to avoid eating at night. If your shift is longer than 8 hours, then you should consider 15-minute naps as allowed, every four hours if your job requires high vigilance and minimal errors. When your shift is over, the drive home is the most dangerous time for sleepiness. If you are anticipating a long commute, you may want to sleep for 30-90 min at work prior to commuting home. If you have a short commute, you should wear dark glasses on the ride home to avoid the alerting effects of sunlight. You can eat a light meal at this time but should then immediately go to bed. Keep your home and bedroom darkened and expose yourself to bright light on awakening. You should not try to do waking activities on arrival home (i.e., watch television, check email, shopping), but save these for when you awaken prior to your next night shift.
What can I do if I must work rotating shifts?
Rotating shifts can be extremely challenging, as this requires the body to make frequent adaptations and adjustments. Night shifts may be easier to adjust to, rotating shifts are often desired to allow for more normal social interaction with friends and family who may be daytime workers. It is generally easier to have shifts start progressively later in the day (moving clockwise from morning to afternoon to evening shifts), then earlier in the day (counterclockwise, following an afternoon shift with a morning shift). Shifts may last six hours, eight hours, ten hours or twelve hours depending on whether overlapping coverage or brief periods of normal nocturnal sleep are desired by everyone. For example, if shifts are 7 AM to 3 PM, 3 PM to 12 midnight, and then 12 midnight to 7 AM, then each shift gets some normal nighttime hours to sleep (i.e., normal night, 1 AM – 7 AM and 6-11 PM, respectively). Workers can be moved directly from shift to shift over 24 hours and rotate through the schedule at a weekly interval or maintain shifts for one week or more before rotating. If there is a break between shifts, then moving the wake-up time each day over the time allowed my help to diminish the effects of the rotation. Again, difficulty adjusting to this schedule may be mitigated using room darkening and sunglasses, light therapy, caffeine and prescription stimulants, sleep aids and prescriptive sedative hypnotics. Tolerance for rotating schedules and shift work is also affected by age and underlying sleep patterns prior to shift work.
How much sleep does a teenager need?
Teenagers need more sleep time than almost any other age group, some teenagers with optimal daytime functioning after 10-12 hrs. of sleep. The teenage body is going through dramatic growth and maturation which is hormonally driven. Hormones, such as growth hormone, are secreted during the night. While many teenagers will get enough sleep, it is quite common that the time at which they desire to sleep is at odds with their educational responsibilities. Teenagers frequently want to go to bed late and get up late (delayed sleep phase). In our current culture, teenagers prefer to stay up into the early morning hours. During this time, they increase their light exposure (television, cell phones, computer, or video games), which makes it more difficult to fall asleep, then only 3-5 hours into their 10-hour sleep when parents are trying to awaken them for school. This usually starts on the weekends when teens can sleep into the late morning. This leads to an inconsistent wake time, which further disrupts the sleep schedule for Monday and Tuesday and then this becomes a daily problem. If suddenly asked to go to bed at 9 or 10 PM, even the most agreeable teenager will be unable to, and parent-teenager conflicts ensue. Luckily, there are ways to correct this.
What should I do if my teenager can’t wake up for school?
Sleep is a habit and a process. As discussed above, when the routine for sleep is disrupted, either intentionally or by timing and light exposure it can lead to insomnia, impaired awakening and decreased daytime functioning. Thankfully, this can be corrected by intentionally adjusting the timing and light or dark exposure in a stepwise fashion. The three ways this is accomplished is by sleep hygiene (behavioral therapy), chronotherapy (timing of the onset of sleep-wake), and phototherapy (timing of light or dark exposures). Medications can be used to assist or enhance this process such as Ramelteon (artificial low dose melatonin) or sedative hypnotics (sleeping pills) if time is limited and the problem is severe.
The first step is always behavioral changes. Teenagers need to be reminded that the bed and the bedroom are for sleep. Television, computers, and cell phones should be removed from the bedroom and avoided after 9 PM. Teens should be advised not to go to the bedroom until sleepy, and not to stay in bed awake for more than 15 min. As tolerated, the wake time should be moved by 15 min intervals weekly or every 2-3 days. Weekdays and weekends are treated the same, with the same expected wake-up time and bedtime rules. Daytime sleep after the desired set wake time and naps should be limited to 15 min, after which the teen is asked to get up and be active for 15 min before being allowed to return to another 15 minute nap (and continue this cycle as needed).
Moving the wake-up time may be more difficult than traditional chronotherapy. Getting up earlier is always harder than staying up later each night. If the teenager is on summer break (or medical leave) and time allows, it may be easier to advance the bedtime daily by 3 hours (i.e., going to bed three hours later) progressively each 1-2 days until the desired wake time is reached. Once the desired wake time is reached, again this should be maintained for both weekdays and weekends.
Finally, exposure to natural daylight in the morning, or prescription artificial lights, may help to assist to solidify early morning wake-up. This is usually encouraged from 6-9 AM for 30- to 60-minute intervals. Daylight is the easiest and most readily available. However, prescription lighting may be of benefit in the winter months when daylight is less. With prescription lighting, there are several guidelines to be followed to avoid complications and to receive effective therapy.
Why can’t a teenager just stay on their own schedule?
There are two main reasons for adjusting a teenager’s delayed sleep schedule. The first is for practical reasons. While it is true that students can go to night school and seek night shift employment, the vast majority will have educational and future employment during the daytime hours. It is beneficial that they start good sleep habits early so that they may adjust to this desired schedule.
Secondarily, either because of physical stress, social or societal pressure or both. It has been demonstrated that teenagers who remain on this delayed sleep schedule (going to bed at 2-4 AM), have a higher tendency towards depression and alcoholism as well as other physical ailments. Once again, a daytime wake and nocturnal sleep schedule should be more desirable.
What if I can’t stay awake in the evening and can’t stay asleep in the morning?
In a dramatic contrast to teenagers, mature adults often have difficulty staying awake in the early evening, and then find themselves unable to stay in bed and awake at or before dawn in the morning. This is commonly referred to as an abnormal advance of the sleep-wake schedule (sleep onset and awakening earlier than expected). It may be disruptive to their social life as they may limit their time away from home after dinner with friends and may find themselves alone and bored being awake in the morning and having to wait several hours before starting daily activities (i.e., breakfast, exercise, errands or shopping, et cetera). Usually, people with this trouble will benefit from late afternoon or early evening light exposure (i.e., a walk outside in the daylight before or after dinner), and delaying bedtime for 15 min a week until an acceptable wake time is achieved.
What if my sleep is completely irregular (non-24-hour disorder)?
It is also called free running or hypernychthemeral sleep disorder. It is more commonly seen in people who have severely impaired vision or blindness, as light is the most powerful controller of sleep timing. In this disorder, the brain otherwise ignores normal cues for the timing of sleep (light or dark, activity, et cetera) and the onset of sleep is progressively delayed from day to day. Sleep onset can occur during the daytime or nighttime in a cyclical pattern which can be recognized by a sleep diary (sleep log) or with actigraphy (motion or activity detector). The goal of treatment is to reestablish good nighttime sleep with improved daytime functioning. If vision is good, phototherapy (sunlight or light box) exposure in morning may be beneficial. Medications which can influence the timing of sleep, such as Ramelteon and tasimelteon) are sometimes used to treat this condition. These medications are similar but safer than over the counter melatonin. All melatonin-related products can lead to changes in blood pressure, blood sugar, diabetes, depression, infertility, and seizures and should only be taken under the supervision of a physician.