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NASA is to test color-changing lights on the International Space Station (ISS) as part of efforts to help astronauts on board sleep.
The US space agency will initially swap a fluorescent panel with a solid-state lighting module (SSLM) containing LEDs which produces a blue, whitish or red-colored light depending on the time.
It says the move may help combat insomnia which can make depression, sickness and mistakes more likely.
The test is due to take place in 2016.
News site Space.com reported that the equipment is being made by Boeing and the project has an $11.2 million budget.
Studies on Earth suggest humans and other creatures follow what is known as a circadian rhythm – a 24-hour biological cycle involving cell regeneration, urine production and other functions critical to health.
Research indicates that it is regulated by a group of cells in a portion of the brain called the hypothalamus which respond to light information sent by the eye’s optic nerve, which in turn controls hormones, body temperature and other functions than influence whether people feel sleepy or wide awake.
The aim of the experiment is to simulate a night-day cycle to minimize sleep disruption caused by the loss of its natural equivalent on the station.
NASA is to test color-changing lights on the ISS as part of efforts to help astronauts on board sleep
When the SSLMs are colored blue the aim is to stimulate melanopsin – a pigment found in cells in the eye’s retina which send nerve impulses to parts of the brain thought to make a person feel alert.
Blue light is also believed to suppress melatonin – a hormone made by the brain’s pineal gland which makes a person feel sleepy when its levels rise in their blood.
By switching from blue to red light – via an intermediary white stage – this process should be reversed, encouraging a feeling of sleepiness.
NASA has previously warned sleep problems among its crews on other missions were also common.
“On some space shuttle missions up to 50% of the crew take sleeping pills, and, over all, nearly half of all medication used in orbit is intended to help astronauts sleep,” it said in 2001.
“Even so, space travellers average about two hours sleep less each night in space than they do on the ground.”
Derk-Jan Dijk, professor of sleep and physiology at the University of Surrey, said NASA’s test reflects the latest findings closer to home.
“It hasn’t been until recently that we started to realize that artificial light, as we see it or are exposed to it in the evening, will have an effect on our alertness and subsequent sleep.
“It turns out there are receptors in the eye which are tuned toward blue light. Adding blue light to artificial lights visible during the day can actually help us to be alert, but if there is too much blue light in the artificial lights at night that may disrupt sleep.
“So, varying the spectral composition of light does make sense from a circadian perspective, and better regulating artificial sleep-wake cycles may indeed benefit astronauts’ sleep in space.”
NASA adds there could be spin-off benefits for the population at large.
“A significant proportion of the global population suffers from chronic sleep loss,” said Daniel Shultz at the Kennedy Space Center.
“By refining multipurpose lights for astronauts safety, health and well-being in spaceflight, the door is opened for new lighting strategies that can be evolved for use on Earth.”
Scientists have found that sleeping for an hour or more extra a night can dramatically improve an individual’s alertness and reduce their sensitivity to pain.
In fact, say the researchers, getting nearly 10 hours a night – rather than the recommended 8 – is more effective at reducing pain than taking the drug codeine.
The study used 18 healthy, pain-free volunteers who were randomly assigned either four nights of their normal sleep pattern or four nights of 10 hours in bed.
The American researchers measured daytime sleepiness using the multiple sleep latency test – a standard method used by doctors to diagnose sleep problems in which brain waves, eye movement, heart rate and muscle tone are measured.
Pain sensitivity was assessed using a heat source.
Results showed the extended sleep group slept 1.8 hours more per night than those on a regular sleeping pattern. This was associated with increased daytime alertness and significantly less pain sensitivity.
Those getting more sleep were able to keep their finger on a heat source for 25% longer, showing a loss of pain sensitivity.
Scientists have found that sleeping for an hour or more extra a night can dramatically improve an individual’s alertness and reduce their sensitivity to pain
The findings, published in the journal Sleep, also revealed the magnitude of this increase is greater than the effect found in a previous study of 60 mg of codeine.
The results, combined with data from previous research, suggest increased pain sensitivity in tired people is the result of their underlying sleepiness.
Dr. Timothy Roehrs, an expert in sleep disorders and their treatment based at the Henry Ford Hospital in Detroit, said: “Our results suggest the importance of adequate sleep in various chronic pain conditions or in preparation for elective surgical procedures.
“We were surprised by the magnitude of the reduction in pain sensitivity, when compared to the reduction produced by taking codeine.”
A bad sleep may be an early sign of Alzheimer’s if a study in mice also applies to people, say researchers.
Clumps of protein, called plaques, in the brain are thought to be a key component of the illness.
A study, published in the journal Science Translational Medicine, showed that when plaques first developed, the mice started having disrupted sleep.
The hunt for early hints that someone is developing Alzheimer’s is thought to be crucial for treating the disease.
A bad sleep may be an early sign of Alzheimer's if a study in mice also applies to people
People do not show problems with their memory or clarity of thought until very late on in the disease. At this point, parts of the brain will have been destroyed, meaning treatment will be very difficult or maybe even impossible.
It is why researchers want to start early, years before the first symptoms.
One large area of research is in plaques of beta amyloid which form on the brain.
Levels of the beta amyloid protein naturally rise and fall over 24 hours in both mice and people. However, the protein forms permanent plaques in Alzheimer’s disease.
Experiments at Washington University showed that nocturnal mice slept for 40 minutes during every hour of daylight. However, as soon brain plaques started to form the mice were sleeping for only 30 minutes.
One of the researchers, Prof. David Holtzman, said: “If sleep abnormalities begin this early in the course of human Alzheimer’s disease, those changes could provide us with an easily detectable sign of [the disease].”
“If these sleep problems exist, we don’t yet know exactly what form they take, reduced sleep overall or trouble staying asleep or something else entirely.”
However, findings in mice do not always apply to people are there are many reasons for disrupted sleep.
Scientists say that having regular lie-ins in old age can bring on dementia.
Getting too much or too little sleep increases your mental age by two years, researchers showed.
There is what scientists call the “goldilocks zone”, seven hours, which is neither too much nor too little.
A series of studies presented at an Alzheimer’s conference in Vancouver shows when it comes to mental decline sleep can play an important part.
It adds to evidence that poor sleep quality and quantity in the elderly increases the risk of a range of illnesses – including heart disease and diabetes.
Dr. William Thies, of the Alzheimer’s Association in the US who organized the annual meeting, said: “We know sleep patterns change as people age and that poor sleep affects overall health.
“What we don’t know for certain is whether poor sleep has long-term consequences on cognitive function.”
He said the latest research suggests cognitive health declines over the long term in some people with sleep problems.
Getting too much or too little sleep increases your mental age by two years
Dr. William Thies said: “The good news is tools already exist to monitor sleep duration and quality and to intervene to help return sleep patterns to normal.
“If we do this, there is the possibility that we may also help people preserve their cognitive health, but that needs to be tested.”
Previous studies have suggested sleep duration shorter or longer than the recommended seven hours per day may increase the risk of cardiovascular disease and type 2 diabetes.
But little research has been carried out on its affect on cognition among older individuals.
So Dr. Elizabeth Devore, of Brigham and Women’s Hospital, Boston, and colleagues followed up over 15,000 retired nurses aged 70 or older every other year for six years.
Those who slept five hours or less or nine hours or more per day had lower average cognition than those who slept seven hours.
Too little or too much sleep was cognitively equivalent to ageing by two years.
The women were recruited for the long-term study in their early 40s and those whose sleep changed by two hours per day or more in later life had worse cognitive function than those with no change, independent of their initial duration.
In a small sample of women who gave blood samples declining ratios of proteins that suggest Alzheimer’s disease brain changes were present in those who slept less or more than seven hours.
Dr. Elizabeth Devore said: “Our findings support the notion that extreme sleep durations and changes in sleep duration over time may contribute to cognitive decline and early Alzheimer’s changes in older adults.
“The public health implications of these findings could be substantial, as they might lead to the eventual identification of sleep- and circadian- based strategies for reducing risk of cognitive impairment and Alzheimer’s.”
As people age, they are more likely to develop problems with sleeping, such as insomnia, sleep apnea and disruptions in circadian rhythm that follow a 24-hour cycle.
Another five year study of 1,300 older women by California University researchers showed participants with sleep apnoea had more than twice the odds of developing dementia compared with those who did not have sleep-disordered breathing.
Women who developed a disruption of their body clock were also at increased risk of dementia and those with greater nighttime wakefulness were more likely to score worse on tests of global cognition and verbal skills.
Dr. Kristine Yaffe said: “We believe these results indicate the relationship between sleep disordered breathing and dementia may be connected to the decrease in oxygen associated with sleep apnoea and not to disrupted patterns of sleep.
“Overall, our findings support a relationship between sleep disturbances and cognitive decline in late age.
“They suggest health practitioners should consider assessing older people with sleep disorders for changes in cognition.”
She said with additional long-term research treatment of sleep disorders may be a promising method of delaying the development of dementia.
A third study of nearly 5,000 over 65 year-olds showed excessive daytime sleepiness – reported by 17.9% of participants – independently increased the risk of cognitive decline along with difficulty maintaining sleep – reported by 63.5%.
Dr. Claudine Berr, of the National Institute of Health and Medical Research in Montpellier, France, said: “These results suggest excessive daytime sleepiness may be an early predictor of cognitive decline and sleep complaints should be adequately evaluated in older persons.”
According to US researchers, children who snore, or who have other night-time breathing conditions, are at risk from behavioral problems.
Sleep apnoea and snoring made conditions such as hyperactivity more likely later on, researchers said.
The study, published in the US journal Pediatrics, looked at data on 11,000 children living in the UK.
Lead researcher Dr. Karen Bonuck, from the Albert Einstein College of Medicine at Yeshiva University in New York, said the sleep problems could be harming the developing brain.
One estimate suggests one in 10 children regularly snores and 2% to 4% suffer from sleep apnoea, which means the breathing is obstructed and interrupted during sleep.
Often enlarged tonsils or adenoids are to blame for the conditions.
According to US researchers, children who snore, or who have other night-time breathing conditions, are at risk from behavioral problems
In adults, the result can be severe day-time tiredness, and some studies have hinted that behavioral problems such as attention-deficit hyperactivity disorder might be linked to the condition in children.
The latest study is sufficiently large to offer a clearer view of this.
Parents were asked to fill in a questionnaire in which both the level of snoring and apnoea were recorded in the first six or seven years of life, and contrasted with their own assessment of the child’s behavior.
Dr. Karen Bonuck said that children with breathing issues during sleep were between 40% and 100% more likely to develop “neurobehavioral problems” by the age of seven.
She believes that the sleep breathing issues could cause behavioral problems in a number of ways – by reducing the supply of oxygen to the brain, interrupting the “restorative processes” of sleep or disrupting the balance of brain chemicals.
She said: “Until now, we really didn’t have strong evidence that sleep-disordered breathing actually preceded problematic behavior such as hyperactivity.
“But this study shows clearly that symptoms do precede behavioral problems and strongly suggests that they are causing these problems.”