circadian system

How to Enjoy Restorative Sleep While Being Treated for Cancer

By: Scott Sanders

When you’re in the midst of cancer treatment, healthful, restorative sleep is crucial for your well-being.  Not only does slumber help you physically, it’s a key to your mental wellness. Here’s how to ensure you get the sleep you need without resorting to prescription medications.  


Healing power


The world we live in can lead you to believe sleep is a waste of time, especially since you don’t appear to be accomplishing anything while snoozing.  However, sleep is necessary for healingthe body and mind.  Your body appears to go through a restoration process while you sleep, helping you recover from the previous day’s events and preparing you for the next morning.  Your bones, skin, and even your brain don’t manage as well when you try to go with insufficient sleep, and on top of that, your immune function is reduced.  It’s also a strain on heart health, more difficult to stay at a healthy weight, and your liver can be stressed, creating a situation where your body can struggle to detoxify itself.  


US News points out sleep is linked with how our bodies regulate cell growth, which makes some scientists all the more inclined to encourage cancer patients toward full nights of high-quality sleep. Unfortunately, some research indicates many patients face sleep deprivationin conjunction with cancer treatment.  Thankfully, there are many things you can do to improve your slumber, and snag those much-needed z’s.


Sleep-friendly environment


Ensuring your bedroom is conducive to a good night’s sleep is a great starting point. Begin with the general atmosphere of the room.  Is it cool and comfortable?  Some experts feel the optimal sleep temperatureis around 65 degrees, and you should adjust your thermostat accordingly.  A dark room is also helpful, so consider installing appropriate window treatments.  Having clean, refreshing air can boost sleep quality as well, especially if you have allergies or asthma.  Check that your air filters are changed routinely to maintain good in-home air quality, and use filters designed to help clear your air of allergens; filters with a MERV rating of at least 11are recommended in order to reduce 95 percent of the airborne debris, like mold spores and pet dander, that threaten your sleep and overall health.  


Catch some sunshine


A dark, cool, comfortable room can help you sleep at night, and the other side of that coin is enjoying sunlight in the daytime can help keep your body rhythm on track.  Getting some sunshine, especially in the morning hours, can improve your sleep by regulating serotonin and cortisol release, encouraging your body to wind down come nighttime.  It’s an opportunity to boost your vitamin D production as well, which some studies indicate can contribute to better sleep at night.  What’s more, Stanford Medicine notes a littlegreen spaceappears to go a long way toward improving sleep, so consider spending time in the morning sitting on your porch and admiring the trees, taking a stroll through the neighborhood with your dog, or settling onto a park bench and feeding the birds.


Find a healthy routine


Sunlight is just one facet of triggering your body toward a healthy sleep cycle.  You can also help set your body’s clock much in the way you would for a child, by embracing a set sleep schedule.  Most people do best with 7 to 9 hours of sleep, although depending on your situation and biological makeup, you may need to break it into routine nap sessions. Some people find a single sleep session of a few hours offset by several naps through the day fits best, and some people benefit from planning several napping periods over the course of 24 hours.


Whatever schedule fits, a bedtime routine can encourage your mind and body to relax. For instance, try doing some meditation exercises, listening to restful music, or sipping some herbal tea.  There are soothing poemsyou can read, or if you need to express yourself, consider journaling.  By doing the same thing at the same time on your chosen schedule, it’s a signal to your body and mind that sleep is coming.  


When you’re in cancer treatment, sufficient slumber is vital.  Evaluate your environment, spend time in the sun, and embrace a healthy routine.  Your mind and body need to heal, and sleep can help.  

Preschoolers exposed to nighttime light lack melatonin

One hour lowers sleep-promoting hormone 88 percent

March 5, 2018

Science Daily/University of Colorado at Boulder

A new study found that preschoolers exposed to bright light at bedtime had an 88 percent reduction in melatonin levels. Anatomical differences in their young eyes may make them more vulnerable to adverse impacts of bright light, the researchers say.


Exposing preschoolers to an hour of bright light before bedtime almost completely shuts down their production of the sleep-promoting hormone melatonin and keeps it suppressed for at least 50 minutes after lights out, according to new University of Colorado Boulder research.


The study, published today in the journal Physiological Reports, is the first to assess the hormonal impact nighttime light exposure can have on young children.


The study comes at a time when use of electronics is rapidly expanding among this age group and adds to a growing body of evidence suggesting that-because of structural differences in their eyes-children may be more vulnerable to the impact light has on sleep and the body clock.


"Although the effects of light are well studied in adults, virtually nothing is known about how evening light exposure affects the physiology, health and development of preschool-aged children," said lead author Lameese Akacem, a CU Boulder instructor and researcher in the Sleep and Development Lab. "In this study we found that these kids were extremely sensitive to light."


For the study, the researchers enrolled 10 healthy children ages 3 to 5 years in a seven-day protocol. On days one through five, the children followed a strict bedtime schedule to normalize their body clocks and settle into a pattern in which their melatonin levels began to go up at about the same time each evening.


On day six, Akacem's team came into the children's homes and created a dim-light environment, covering windows with black plastic and swapping out existing lights with low-wattage bulbs. This ensured that all the children were exposed to the same amount of light-which can influence melatonin timing and levels-before samples were taken.


That afternoon, the researchers took periodic saliva samples to assess melatonin levels at various times. The following evening, after spending the day in what they playfully referred to as "the cave," the children were invited to color or play with magnetic tiles on top of a light table emitting 1,000 lux of light (about the brightness of a bright room) for one hour.


Then the researchers took samples again, comparing them to those taken the night before.


Melatonin levels were 88 percent lower after bright light exposure. Levels remained suppressed at least 50 minutes after the light was shut off.


Direct comparisons between this study and studies in adults must be made with caution because of differing research protocols, the researchers stress. However, they note that in one study, a one-hour light stimulus of 10,000 lux (10 times that of the current study) suppressed melatonin by only 39 percent in adults.


"Light is our brain clock's primary timekeeper," explains senior author Monique LeBourgeois, an associate professor in the Department of Integrative Physiology. "We know younger individuals have larger pupils, and their lenses are more transparent. This heightened sensitivity to light may make them even more susceptible to dysregulation of sleep and the circadian clock."


She explains that when light hits the retina in the eye in the evening, it produces a cascade of signals to the circadian system to suppress melatonin and push back the body's entrance into its "biological night." For preschoolers, this may not only lead to trouble falling asleep one night, but to chronic problems feeling sleepy at bedtime.


Melatonin also plays a role in other bodily processes, regulating temperature, blood pressure and glucose metabolism.


"The effects of light at night exposure can definitely go beyond sleep," Akacem said.


The study sample size was small and it used only one intensity of light, 1,000 lux, which is far greater than the intensity of a typical handheld electronic device, she notes.


With a new $2.4 million grant from the National Institutes of Health, LeBourgeois recently launched a study in which she will expose 90 children to light of different intensities to determine how much it takes to impact the circadian clock.


"The preschool years are a very sensitive time of development during which use of digital media is growing more and more pervasive," Le Bourgeois said. Use of electronic media among young children has tripled since 2011. "We hope this research can help parents and clinicians make informed decisions on children's light exposure."


The takeaway for parents today: Dim the lights in the hours before bedtime.

Night owls have higher risk of dying sooner

Evening types have 10 percent higher risk of dying than morning counterparts

April 12, 2018

Science Daily/Northwestern University

Night owls -- people who prefer to stay up late and sleep late -- have 10 percent higher risk of dying sooner than larks, people who go to bed early and rise early, reports a new study. This is the first study to show 'owls' have higher risk of mortality. Owls also suffer from more diseases and disorders than morning larks. Employers should allow greater flexibility in working hours for owls, scientists said.


The study, on nearly half a million participants in the UK Biobank Study, found owls have a 10 percent higher risk of dying than larks. In the study sample, 50,000 people were more likely to die in the 6½ -year period sampled.


"Night owls trying to live in a morning lark world may have health consequences for their bodies," said co-lead author Kristen Knutson, associate professor of neurology at Northwestern University Feinberg School of Medicine.


Previous studies in this field have focused on the higher rates of metabolic dysfunction and cardiovascular disease, but this is the first to look at mortality risk.


The study will be published April 12 in the journal Chronobiology International.


The scientists adjusted for the expected health problems in owls and still found the 10 percent higher risk of death.


"This is a public health issue that can no longer be ignored," said Malcolm von Schantz, a professor of chronobiology at the University of Surrey. "We should discuss allowing evening types to start and finish work later, where practical. And we need more research about how we can help evening types cope with the higher effort of keeping their body clock in synchrony with sun time."


"It could be that people who are up late have an internal biological clock that doesn't match their external environment," Knutson said. "It could be psychological stress, eating at the wrong time for their body, not exercising enough, not sleeping enough, being awake at night by yourself, maybe drug or alcohol use. There are a whole variety of unhealthy behaviors related to being up late in the dark by yourself."


In the new study, scientists found owls had higher rates of diabetes, psychological disorders and neurological disorders?


Can owls become larks?


Genetics and environment play approximately equal roles in whether we are a morning or a night type, or somewhere in between, the authors have previously reported.


"You're not doomed," Knutson said. "Part of it you don't have any control over and part of it you might."


One way to shift your behavior is to make sure you are exposed to light early in the morning but not at night, Knutson said. Try to keep a regular bedtime and not let yourself drift to later bedtimes. Be regimented about adopting healthy lifestyle behaviors and recognize the timing of when you sleep matters. Do things earlier and be less of an evening person as much as you can.


Society can help, too


"If we can recognize these chronotypes are, in part, genetically determined and not just a character flaw, jobs and work hours could have more flexibility for owls," Knutson said. "They shouldn't be forced to get up for an 8 a.m. shift. Make work shifts match peoples' chronotypes. Some people may be better suited to night shifts."


In future research, Knutson and colleagues want to test an intervention with owls to get them to shift their body clocks to adapt to an earlier schedule. "Then we'll see if we get improvements in blood pressure and overall health," she said.


The switch to daylight savings or summer time is already known to be much more difficult for evening types than for morning types.


"There are already reports of higher incidence of heart attacks following the switch to summer time," says von Schantz. "And we have to remember that even a small additional risk is multiplied by more than 1.3 billion people who experience this shift every year. I think we need to seriously consider whether the suggested benefits outweigh these risks."


How the study worked


For the study, researchers from the University of Surrey and Northwestern University examined the link between an individual's natural inclination toward mornings or evenings and their risk of mortality. They asked 433,268 participants, age 38 to 73 years, if they are a "definite morning type" a "moderate morning type" a "moderate evening type" or a "definite evening type." Deaths in the sample were tracked up to six and half years later.


The study was supported by the University of Surrey Institute?of Advanced Studies Santander fellowship and the National Institute of Diabetes and Digestive and Kidney Diseases grant R01DK095207 from the National Institutes of Health.

New study finds shifted sleep-wake cycles affect women more than men

April 18, 2016

Science Daily/University of Surrey

A new study involved the assessment of performance in participants being placed on 28-hour days to shift the sleep-wake cycle out of phase with the brain (circadian) clock. Performance was more affected in women than in men, the results show. Researchers warn that this study has significant implications for female nightshift workers such as nurses, security guards and police officers.


Researchers placed 16 male and 18 female participants on 28-hour days in a controlled environment without natural light-dark cycles, at the Surrey Clinical Research Centre. This effectively desynchronised the sleep-wake cycle from the brain's 24-hour (circadian) clock, similar to jet lag or a shiftwork scenario.


Every three hours during the awake period, participants performed a wide range of tests, including self-reported assessments of sleepiness, mood and effort, and objective tests of cognitive performance which included measures of attention, motor control and working memory. Brain electric activity (EEG) was monitored continuously during sleep. The results revealed that in both men and women self-reported assessments were more sensitive to the effects of time awake and circadian clock than the many objective measures of performance. However, crucially, the circadian effect on performance was significantly stronger in women than in men such that women were more cognitively impaired during the early morning hours, which in the real world typically coincides with the end of a night shift.


Co-author, Dr Nayantara Santhi from the University of Surrey, said, "We show for the first time that challenging the circadian clock affects the performance of men and women differently. Our research findings are significant in view of shiftwork-related cognitive deficits and changes in mood. Extrapolation of these results would suggest that women may be more affected by night-shift work than men."


Senior author, Professor Derk-Jan Dijk, continued, "These results show that in both men and women circadian rhythmicity affects brain function and that these effects differ between the sexes in a quantitative manner for some measures of brain function."


"Overall the findings illustrate how important it is to include both men and women in research studies and to use a wide range of subjective and objective indicators of brain function," added Professor Dijk.

Light-Treatment Device to Improve Sleep Quality in the Elderly

June 1, 2009

Science Daily/Rensselaer Polytechnic Institute

Sleep disturbances increase as we age. Some studies report more than half of seniors 65 years of age or older suffer from chronic sleep disturbances. Researchers have long believed that the sleep disturbances common among the elderly often result from a disruption of the body’s circadian rhythms — biological cycles that repeat approximately every 24 hours.


In recent years, scientists at Rensselaer Polytechnic Institute’s Lighting Research Center and elsewhere have demonstrated that blue light is the most effective at stimulating the circadian system when combined with the appropriate light intensity, spatial distribution, timing, and duration. A team at the Lighting Research Center (LRC) has tested a goggle-like device designed to deliver blue light directly to the eyes to improve sleep quality in older adults.


“Light and dark patterns are the major synchronizer of circadian rhythms to the 24-hour solar day,” said Mariana Figueiro, Ph.D., Lighting Research Center Light and Health Program director and principal investigator on the project.  “Light stimulus travels through the retina, the light-sensitive nerve tissue lining the back wall of the eye, to reach the master clock in the brain. However, a combination of age-related changes in the eye and a more sedentary lifestyle may reduce the amount of light stimulus reaching an older person’s retina, therefore reducing the amount of light for the circadian system.”


As we age, the lens in the eye thickens and the pupil shrinks, reducing the amount of light passing through to the retina.  Making matters worse, in some cases, such as with persons with Alzheimer’s disease, the circadian system may require a stronger light stimulus due to deteriorating neural processes in the brain.  These physical and neural changes can lead to muted signals to the circadian system. Factor in environmental influences, such as an indoor lifestyle with less access to daylight, and you have a perfect scenario for the development of irregular sleep-activity patterns, according to Figueiro.


The research team explains that a marked increase in daytime lighting levels can counteract the age-dependent losses in retinal light exposure by providing a stronger signal to the circadian system.  However, the color and intensity of commercially available lighting systems, like those used in senior residences, assisted-living facilities, and nursing homes, are designed for visual effectiveness and minimal energy use and not necessarily efficacious for generating light to stimulate the older circadian system.


Commercially-available “white” light sources advertised to treat circadian-related sleep disorders are usually very bright light and can cause glare and compromise compliance.


In this project, the light-treatment prototype tested by Figueiro’s team was developed by, LLC, based on prior LRC light and health research. The device offers an alternative approach using specially designed goggles that deliver blue light spectrally tuned for optimum circadian response.


“The goal of this phase of the development project was to create a device in a smaller form factor or envelope that allowed for social inclusion and end-user mobility, while still delivering the required dose of light,” said Senior Developer Philip H. Bonello, Ph.D.


The device was worn by eleven subjects between the ages of 51 and 80 years of age. Each subject was exposed to two levels of blue light (about 50 lux and 10 lux) from the personal light-treatment device for 90 minutes on two separate nights.  Blood and saliva samples were collected at prescribed times to assess levels of nocturnal melatonin, a hormone used as a marker for the circadian clock, with high levels at night when a person is in a dark environment and low levels during the day.


After only one hour of light exposure, the light-induced nocturnal melatonin suppression level was about 35 percent for the low light level and about 60 percent for the high light level. In addition, the higher level of blue light suppressed nocturnal melatonin more quickly, to a greater extent over the course of the 90-minute exposure period, and was maintained after 60 minutes.


Having demonstrated its stimulation effect on the circadian system, the researchers believe the device could be subsequently used to increase sleep consolidation and efficiency in older subjects when worn for a prescribed duration at an appropriate time.


“The study suggests that the light goggles might be a practical, comfortable, and effective way to deliver light treatment to those suffering from circadian sleep disorders. The next steps are to conduct field studies where we will be testing the effectiveness of this personal light-treatment device on those suffering from circadian-related sleep disorders, while also verifying the acceptance of the device among the test groups,” said Figueiro.

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