Searching For Shut Eye: Study Identifies Possible Sleep Gene

While scientists and physicians know what happens if you don’t get six to eight hours of shut-eye a night, investigators have long been puzzled about what controls the actual need for sleep. Researchers at the University of Pennsylvania School of Medicine might have an answer, at least in fruit flies. In a recent study of fruit flies, they identified a gene that controls sleep.
“We spend -- or should spend -- a third of our lives sleeping,” says Amita Sehgal, PhD, Professor of Neuroscience and an Investigator with the Howard Hughes Medical Institute (HHMI). “The idea that so much time is spent in sleep is intriguing. Also, sleep deprivation has serious health consequences and impairs cognitive function.”
This study was published in the latest Science.
Fruit flies typically sleep 12 hours a day. Sehgal and her team studied 3,500 fruit flies and found mutants that survived on little to no sleep – one to two hours a day or none at all. The sleepless flies had a mutation of a gene that Sehgal and her team have named Sleepless. They believe the Sleepless gene encodes a protein that affects whether potassium ion channels in the brain stay open or closed. When the channels are open, the brain is connected and working – the fly is awake. When closed, the channel shuts down and the fly sleeps. The insomniac fruit flies had less of the Sleepless-produced protein.
The lack of sleep didn’t come without consequences. The Sleepless fruit flies lived about half as long as fruit flies that did not carry the mutation. They also experience impaired coordination and restlessness in their few hours of sleep.
Sleep is regulated by two processes: circadian and homeostatic. Circadian regulation affects the timing of sleep, and the homeostatic mechanism affects the need for sleep. The Sleepless gene affects the homeostatic mechanism.
Sleep isn’t just for humans – it’s been observed in everything from flies to dogs to people, indicating that it’s essential to life. Insufficient and poor-quality sleep is an increasing problem in industrialized nations. In the U.S. alone, about 70 million people suffer from chronic sleep problems, which reduce workplace productivity, affect quality of life and can even be lethal.
“In the long term, we hope that human equivalents of our gene will be isolated and will not only further our understanding of human sleep, but perhaps also serve as drug targets to promote sleep or treat insomnia,” says Sehgal.

Comparing Sleep And Awake Schedules

The newer blue-enriched lights used in light boxes are no more effective at advancing circadian rhythms than the standard white lights that have been in use for decades according to a study by researchers in the Rush University Medical Center Biological Rhythms Research Lab. The study results will be published in the journal Sleep Medicine Vol. 10, issue 3 (April 2009).
These results are important for people who use therapeutic light boxes and scheduled exposure to light and darkness to rest their natural body clocks, such as shift workers and those who have certain sleep issues like delayed sleep phase disorder (DSPD), a condition in which an individual has a biological predisposition to go to bed and awaken on a much later schedule than most people.
Previous research has shown that the human circadian clock is most sensitive to short-wavelength (blue) light, but more research is needed regarding the dosage, timing and wavelength of light treatment.
Researchers at Rush were interested in finding out if bright blue lamps would provide a larger phase advance, or help patients awaken earlier, than the standard bright white lamps commonly used for phase shifting. The study found the blue lamps were no more effective than the standard bright therapy.
“This is good news for people using light treatment because it indicates that the standard white lights that are commercially available work as well as the newer blue-enriched lights. It means that patients are already likely getting a maximal therapeutic response, so there’s no need to rush out and buy a new light box,” said lead author Mark Smith, post-doctoral fellow in the Biological Rhythms Research Laboratory at Rush University Medical Center.
In the study, twenty-two healthy young adults received either a bright white or bright blue-enriched two-hour phase advancing light pulse upon awakening on each of four treatment days. On the first treatment day, the light pulse began eight hours after the dim light melatonin onset, on average about two hours before baseline wake time. On each subsequent day, light treatment began one hour earlier than the previous day, and the sleep schedule was also advanced.
Following the four treatment days, a final phase assessment was conducted. Phase advances of the blue-enriched and white groups were not significantly different.
The effectiveness of the blue-enriched lights at a different light level—less bright—for treatment of different clinical applications, was not tested in this study. According to study authors, blue-enriched lights may be useful for other clinical conditions.

Have Insomnia? Try Aerobic Exercise

Older adults who have insomnia may sleep better if they eliminate the sleeping pills and take up aerobic exercise such as walking or bicycling, according to a new study. Researchers from Northwestern University are the first to evaluate the impact of aerobic exercise on middle-aged and older adults who suffer with insomnia.

Insomnia in America

About 30 to 40 percent of adults have symptoms of insomnia, which is an inability to fall asleep or stay asleep, and waking up not feeling refreshed. Up to 15 percent of adults have chronic insomnia, which is defined as experiencing these symptoms for a month or longer. Insomnia is more prevalent among women than men, and about half of all middle-aged and older adults suffer with this sleep disorder.
Medications called hypnotics are the most common treatment for insomnia, but they are associated with side effects such as memory problems, morning sedation, headaches, and sleepwalking. Relaxation techniques such as yoga, meditation, and exercise, as well as behavioral therapies have all been found to be helpful in varying degrees, depending on the cause of insomnia and consistently an individual uses them.
New Insomnia and Exercise Study
The study included 23 sedentary adults age 55 and older, mostly women, who had symptoms of chronic insomnia. One group was assigned to aerobic exercise for two 20-minutes sessions four times weekly or one 30-to-40 minute session four times weekly, both for 16 weeks. The participants chose at least two activities such as walking, using a stationary bike, or treadmill.
The control group engaged in a recreational or educational activity, such as a lecture or cooking class, which met for 45 minutes three to five times a week for 16 weeks. Subjects in both groups were given information about good sleep habits.
People in the exercise group reported better quality sleep, fewer symptoms of depression, more energy, and less sleepiness during the day. These improvements raised their status from a poor sleeper to good sleeper.
“This is relevant to a huge portion of the population,” according to Phyllis Zee, MD, director of the Sleep Disorders Center at Northwestern Medicine and senior author of the study. “Exercise is good for metabolism, weight management and cardiovascular health and now it’s good for sleep.”
Sleep quality has a critical impact on both physical and mental health. Because insomnia increases as people age, this population is at greater risk of health problems, which are also already more common in older adults. Therefore, “It is essential that we identify behavioral ways to improve sleep,” says Zee. “Now we have promising results showing aerobic exercise is a simple strategy to help people sleep better.”