Sleep and the amateur astronomer: it's 2 a.m., and the stars look dazzling in your scope. But all you can think about is hitting the sack. How can you stay awake for just one more hour? Easy--chew a peppermint!
Should you be concerned about disrupting your sleep cycle? Perhaps. A rare all-nighter won't harm you. However, health risks do arise when you disrupt your normal circadian routine night after night. Here's why:
The circadian (day-night) cycle causes a fluctuation in the body's production of various hormones from the hypothalamus, pituitary, pineal, adrenal, and thyroid glands. Some hormones are made in the dark, some in the light. If you disturb this hormonal production by staying up at night and sleeping during the day, the result can be mood swings, confusion, irritability, depression, and metabolic problems (such as type 2 diabetes). And your immune system can be disrupted too, making you more susceptible to infectious disease.
This is not to say you should give up astronomy. But you should pay serious attention to rebalancing your body chemistry after a night under the stars.
The Science of Sleep
Human sleep has two major components. REM (rapid-eye-movement) sleep occurs when we dream--the brain, eyes, and body muscles are active. Slow-wave sleep, as the name implies, slows your brain's activity. And slow-wave sleep, in turn, is classed as either theta (light sleep or drowsiness) or delta (deep sleep).
Deep sleep is what your body really needs. It's a time of restoration, when stress-related hormones decrease and the anti-aging growth hormone gets a boost. So when trying to catch up after a night's stargazing, it's important to try to maximize delta sleep. You get the restorative benefits of delta sleep for about 15% of the time you're asleep at night but for only 5% of daytime (naptime) sleep. This disparity is most unfortunate for overnight shift workers and astronomers who must rest during the day.
Under normal circumstances, the sleep-inducing brain hormone melatonin is produced between 10 p.m. and 3 a.m., so this is when you fall asleep with ease. But melatonin is only produced in the dark. Visible light triggers enzymes that stop the production of melatonin. Even with your eyes shut, some light is transmitted through your eyelids and then to your brain to awaken you. It only takes the flicker of the bathroom light, a blue or white night-light, the glow from a TV screen, or the light from an opening refrigerator to stop the production of melatonin and block sleep.
Therefore, a great way to enhance deep sleep is to immerse yourself in total darkness. But that's exactly what you want when observing too! When you're out under the stars, you don't want to sleep--you want to stay awake.
Not Just Awake but Alert
Just as with sleep, there are stages of alertness. Your brain can be either in an alpha pattern, which is focused concentration ("in the zone"), or in a beta pattern, which is associated with a more stressful, conscious alertness.
There are effective strategies you can use to keep awake. These days stars can be observed both while outdoors and indoors. When outdoors, low-level red lights are used to maintain dark adaptation. Unfortunately, red light does nothing to stop the typical evening production of melatonin--and you get drowsy.
Professional observers and indeed many amateurs now "observe" on a computer monitor in a comfortable control room. If you're indoors, dark adaptation isn't necessary. Although dim lighting helps if you have to go outside to adjust equipment or to check sky conditions, flooding the control room with bright light will suppress the production of melatonin and help you fight drowsiness.
The connection between light and wakefulness remained elusive until just a few years ago. Then researcher George Brainard (Thomas Jefferson University) and his colleagues found that the eye has a "wake up" photoreceptor in the retina that works independently of the rods and cones needed for sight. Blue-green light (wavelengths from 450 to 490 nanometers) causes this photoreceptor to signal the brain to shut down the production of melatonin. Soon you wake up. This signaling is particularly effective between 1 and 3 a.m., when the desire for sleep is most powerful.
For visual observers, of course, staring at a bright light to stay awake is not a good option, because you're trying to maintain your dark adaptation. So eat instead! You'll wake up your mind and your body by eating foods containing the amino acids tyrosine and phenylalanine. These compounds are used by the brain to produce adrenaline (epinephrine), noradrenaline (norepinephrine), and dopamine--all of which control the oxygen flow to your brain, affecting your logical mind, pleasure center, and hand-eye coordination. Tyrosine and phenylalanine are plentiful in beef, fish, and eggs; vegetarians can choose bananas, almonds, avocados, pumpkin seeds, or sesame seeds. But avoid eating sweets; sugar triggers the production of insulin, which blocks tyrosine and phenylalanine from reaching the brain.
You might also want to turn down the thermostat, because a research team led by Eus J. W. Van Someren (Netherlands Institute for Brain Research) has found that as the temperature of your skin decreases, your core body temperature increases--and so does alertness. In fact, alertness is greatly enhanced by combining white light and lowered temperature. So cool nighttime air might be very helpful to wake you up. (Professional astronomers often take time to get out of the dome or control room to look at the night sky--the reason all stargazers do what we do.)
Even better, go for a walk! Step away from your telescope several times nightly to stretch and relax. Alertness increases immediately after aerobic physical activity. And exercise will lead to better and more effective sleep afterward because it increases the production of melatonin several hours later.
What about drinking coffee? Caffeine does increase wakefulness, by promoting beta brain waves and suppressing theta (drowsiness) waves. Unfortunately, it also blocks alpha waves and can lead to less-focused alertness. If you really need that cup of coffee, drink it early in the evening. James Wyatt (Rush University Medical Center) found that normal, healthy men stayed more alert over a 25-hour period if they took the caffeine equivalent of 2 ounces of coffee once per hour, stretched out over the duration. But if taken late at night, coffee will interfere with unwinding and relaxing. And if it clouds up in the middle of your observing session, you're stuck being wide awake!
A better choice would be munching on peppermints. In 2001 a team led by Josef Ilmberger (Ludwig Maximilians University, Munich) discovered that what's under your nose can affect your mental state. The researchers found that the scents of menthol, peppermint, eucalyptus, and jasmine all enhanced alertness.
A catnap would be an excellent way to sneak in some shuteye. If it's long enough to allow you to experience delta and theta sleep, it can not only be restorative but can also lessen the damaging hormonal interruptions associated with shift work. If you're taking long series of images using computer-automated equipment, catnaps are a definite possibility. You can always set up a watchdog program to sound an alarm if something goes wrong.
If you've traveled to a distant site to observe, then the most important time to stay alert is after you've packed up for the night. Be very cautious driving home. A colleague had a routine of driving home after observing all night. Early one morning, near the end of his half-hour trip, he fell asleep at the wheel, crossed the centerline on a curve, and hit a guardrail. His seat belt and air bags saved him from harm, but his car was totaled.
Now that you're armed with some ways to stay awake, what should you do as dawn approaches? Are some sleep strategies better than others?
As mentioned earlier, getting deep, restorative sleep is essential for your health. Light in your bedroom is troublesome enough with evening sleep--but it's even more disruptive when you're attempting to sleep during daytime. You're fighting your normal circadian rhythm and trying to get your body to make melatonin at the wrong time. Your circadian clock will adjust, as it does when you adjust to a new time zone, but this can take several days. That's not an option for astronomers whose nightly schedule is constantly changing with the weather.
As noted, you get less deep, restorative delta sleep during daytime hours. You also get less of it as you age. Some people can ease into deep sleep by listening to CDs or other soothing sounds, or by using earplugs to block distracting noises. Try to quit observing at least a half hour before dawn, so you can reach your bed in darkness.
It definitely helps to sleep in as dark a room as possible. You can try eyeshades, available at drugstores, but you may not feel particularly comfortable wearing them. Blackout window shades may be necessary to get your bedroom dark enough. Replace white or blue-green night-lights with red ones--red light does not significantly reduce melatonin production but still allows you to see in the dark. Try low-wattage Christmas bulbs or red LED lights. It's very important to turn off the TV and reading lights.
You might consider adding to your natural production of melatonin by taking supplemental tablets. Melatonin is available over-the-counter in the United States and by prescription in Canada, South America, Australia, and most European countries. Used intermittently and in low dosages (1 milligram or less) melatonin is generally considered safe, but before using it you should talk with your health professional. Asthmatics and those with autoimmune disorders (such as arthritis) may find that excessive melatonin worsens their symptoms.
You can also augment your melatonin naturally, through food. There's a good reason why mother's milk puts a baby to sleep: milk protein is high in the amino acid tryptophan, which is needed to make melatonin. Drink milk with something sweet, and your insulin level will increase. Insulin helps tryptophan reach the brain, where it can be converted into melatonin and produce drowsiness. So milk and cookies, eaten a half hour before you intend to sleep, will help your brain make nature's own sleeping pill.
Speaking of which, you might be wondering about taking commercial sleep aids. As described on the previous page, these medications all have some risk of dependency. Herbal medications are not necessarily safe either. For instance, kava and valerian, which operate on the brain's "valium" (benzodiazepine) receptors, are associated with too many side effects to be safely taken on a regular basis.
Instead, try chamomile or lemon-balm tea, which have been shown to be mild sleep aids with no side effects. These may be taken shortly before you intend to sleep. And just as certain scents awaken you, researchers have found that lavender, cedar, and citrus oils have sleep-enhancing effects.
Warmth also aids sleep. According to Van Someren, as the temperature of your skin increases, your core body temperature decreases--and this decline boosts the production of melatonin. So a hot bath taken an hour before you hit the pillow will improve your sleep, particularly restorative slow-wave sleep. Warm ambient temperature, while not as powerful as total darkness, is certainly a sleep aid.
Daytime physical activity increases your body's metabolic rate and its temperature, which in turn increases the production of melatonin in the evening. This leads to better sleep patterns. So, in addition to all its other health benefits, daily exercise is essential to reestablishing circadian balance after long nights of stargazing. On the other hand, exercise should not occur directly before bedtime, as it enhances alertness.
We've summarized the problems associated with staying awake and falling asleep, and what modern science offers as some of the solutions. But every individual will respond a little differently to these suggestions. So let us know what works for you. Drop us an e-mail (sleep@SkyandTelescope.com)--maybe your experiences and solutions can be the basis for a follow-up article!
RELATED ARTICLE: Medical sleep aids.
By Joan E. Roberts
It may be difficult to get to sleep after a long and exciting night stargazing, and you might be tempted to take a chemical sleep aid. Make sure you know the facts first.
The body's natural sleeping pill, melatonin is a hormone produced during sleep. Unless you have asthma, you can safely add to your natural production by taking melatonin in low doses (1 milligram or less). Research has shown that a 0.3- to 1-mg dose is more than sufficient to help you sleep. Unfortunately, it is often sold in 3-mg tablets. High doses may have the opposite effect, stopping your natural production and waking you up. Cut such a pill into thirds or quarters.
If you purchase over-the-counter melatonin, make sure that it has been tested by HPLC (high-pressure liquid chromatography), a test that offers reasonable assurance of the quantity of melatonin in each tablet. (If you find melatonin doesn't work for you, maybe there was none in the tablet!)
Melatonin does not induce dependency even when taken for many months or years, nor are there withdrawal effects or rebound insomnia. However, be aware that melatonin enhances both REM (dream) and non-REM sleep. In some people this can lead to intense dreaming, including nightmares. In any case you should consult with your personal physician before starting any self-medication.
Ramelteon is a melatonin agonist, meaning it occupies the same receptors in the eye and brain as melatonin and does the same job. Because ramelteon does not sit on opiate (morphine) or benzodiazepine (valium) receptors in the brain, it is not as likely to lead to addiction as other sleeping aids.
Antihistamines (Sominex, Nytol, Nyquil)
The active sleep-inducing component found in Nytol, Sominex, Sleep-Eez, and the PM versions of Excedrin, Tylenol, and Anacin is the antihistamine diphendydramine. Most antihistamines cause drowsiness, so these prescription and over-the-counter medications are used to treat insomnia. While antihistamines do not induce dependency and will help you fall asleep, these may have side effects. They are not safe to take if you have high blood pressure, asthma, glaucoma, an enlarged prostate, or bladder problems, or if you are taking antidepressant medication.
Benzodiazepines (Ambien, Sonata, Lunesta)
Benzodiazepines, such as Librium and Valium, were originally developed to treat anxiety. These drugs act by enhancing the body's production of the naturally calming compound GABA (gamma amino butyric acid) in the brain. They were also found to be very useful sleep inducers and were prescribed for severe or disabling insomnia. Although very effective, the first benzodiazepines caused dependency and severe withdrawal symptoms, even when taken for a relatively short time.
The most recent benzodiazepines--zolpidem (Ambien), zaleplon (Sonata), and zopiclone (Lunesta)--likewise both block anxiety and induce sleep. However, they are also habit-forming after just a few weeks' use. They can also produce bad side effects (mood swings, memory loss) when taken with alcohol, and they pose danger to people with preexisting respiratory illness.
Modern benzodiazepines differ from the older versions only in that they are "ultrashort acting"--the effect of Sonata lasts just 1 hour, Ambien 2 1/2 hours, and Lunesta 3 1/2 to 6 1/2 hours--so users experience less residual sleepiness after the drug wears off. Residual (daytime) sleepiness leaves a person with poor coordination, increasing the risk of automobile accidents and falls.
These drugs are meant to be taken very rarely (for example, to counteract jet lag) and not as a treatment for chronic insomnia. Use with extreme caution!
Doze and Don'ts
Strategies for staying awake while stargazing:
* Flood the control room with light.
* Snack on beef, fish, eggs, almonds, avocados, bananas, pumpkin seeds, or sesame seeds. Munch on peppermints, but avoid other sweets.
* Keep the temperature cool.
* Stretch or take a short walk periodically.
* Avoid caffeine late at night.
* Take catnaps.
Strategies for falling asleep after stargazing:
* Wear sunglasses if it's daylight during the trip home.
* Have a sweet with warm milk or cocoa, or drink chamomile or lemon-balm tea.
* Avoid alcohol, which interferes with deep sleep.
* Take a warm bath before going to bed.
* Scent your bedroom with lavender, cedar, or citrus oils.
* Quiet your mind with relaxing music or sounds.
* Keep your bedroom completely dark; use only red night-lights, if needed at all.
* Do aerobic exercises after you wake up.
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|Author:||Caton, Daniel B.; Roberts, Joan E.|
|Publication:||Sky & Telescope|
|Date:||Dec 1, 2006|
|Previous Article:||"Proof" of dark matter?|
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