• For more on this topic see our article Q&A: Natural help for healing stomach ulcers

One in three of us suffers from poor sleep. Stress, computers and other devices as well as a culture of taking work home are often cited as the reason for this, and many of us just accept it as ‘part of modern life’.

But, the cost of this “sleep debt” – is more than just bad moods and a lack of focus. Consistently not getting enough sleep puts you at risk of serious conditions, including obesity, heart disease and diabetes. Previous research has also shown that adults under the age of 65 who get five or fewer hours of sleep a night have a higher risk of death than those who get adequate sleep.

But just what is ‘adequate’ sleep?

In a recent study in the Journal of Sleep Research, scientists at Stress Research Institute, Stockholm University, and the Karolinska Institute, looked at data from 38,000 people in Sweden, collected as part of a larger lifestyle study which ran for 13 years from 1997.

Finding the sleep sweet spot

After adjusting for factors such as gender, body mass index, smoking, physical activity and shift work, the data showed that those under the age of 65 who got five hours of sleep or less seven days a week had a 65% higher rate of premature death than those getting six or seven hours’ sleep every day. Significantly, there was no increased risk of death for those who slept five or fewer hours during the week but then managed eight or more hours’ sleep on weekend days. This suggests that a good lie in at the weekend could be a life saver.

Interestingly, people who slept for eight or more hours, seven days a week, were found to have a 25% higher mortality rate compared with those who kept to six or seven hours a day. The study also found that the link between sleep patterns and mortality disappeared for those aged 65 or older. Indeed the study seemed to suggest that older people (over age 65) seemed to get the sleep they needed more easily.

“Sleep duration is important for longevity,” said lead researcher Torbjörn Åkersted who, along with his team notes that their data shows “that short (weekday) sleep is not a risk factor for mortality if it is combined with a medium or long weekend sleep…This suggests that short weekday sleep may be compensated for during the weekend, and that this has implications for mortality.”

The upshot is simple – make time for a lie in whenever you can. It could just save your life.

• For advice on getting a good nights’ sleep see our article A sleep solutions ‘cheat sheet’

And you are not alone: 90% of us use light-emitting electronic devices, such as smartphones and laptops, in the hour before bed, despite the fact that such behaviour is associated with symptoms of insomnia. The obvious solution is to ditch the technology, but people rarely heed this advice.

Knowing that individuals with insomnia are also unlikely to change their ways, researchers from Columbia University Medical Center tested a method to reduce the adverse effects of evening ambient light exposure, while still allowing use of blue light-emitting devices. Their findings will be published in the January issue of Journal of Psychiatric Research.

Blocking blue light

Smartphones, tablets and other light-emitting devices are lit by LEDs, which have a peak wavelength in the blue portion of the spectrum. Blue light at night suppresses melatonin and increases alertness; the use of amber-tinted lenses that block blue light mitigates these effects.

The Columbia team, led by Ari Shechter, PhD, assistant professor of medical sciences, reasoned that selectively blocking blue light in the hours before bedtime would lead to improved sleep in individuals with insomnia.

To test their theory, the researchers recruited 14 individuals with an insomnia diagnosis to take part in a small study. For seven consecutive nights, participants wore wrap-around frames with amber-tinted lenses that blocked blue light or with clear placebo lenses for two hours before bedtime. Four weeks later, participants repeated the protocol with the other set of glasses.

The researchers found that participants got around 30 minutes extra sleep when they wore the amber lenses compared to the clear lenses. In self-reported sleep surveys, participants also reported greater duration, quality, and soundness of sleep, and an overall reduction in insomnia severity.

An affordable solution

These findings are consistent with prior studies showing a benefit of blue-light-blocking lenses in improving sleep, but should be replicated in larger controlled studies, Shechter said.

“Now more than ever we are exposing ourselves to high amounts of blue light before bedtime, which may contribute to or exacerbate sleep problems,” Shechter said. “Amber lenses are affordable and they can easily be combined with other established cognitive and behavioural techniques for insomnia management.”

Many smartphones screens can now be adjusted to emit amber instead of blue light, and Shechter said these settings should help to improve sleep. “I do recommend using the amber setting on smartphones at night, in addition to manually reducing the brightness levels. But blue light does not only come from our phones. It is emitted from televisions, computers, and importantly, from many light bulbs and other LED light sources that are increasingly used in our homes because they are energy-efficient and cost-effective,” he said.

“The glasses approach allows us to filter out blue-wavelength light from all these sources, which might be particularly useful for individuals with sleep difficulties.”

The use of amber lenses also appeared to reduce blood pressure in the study’s participants (these data are published in the September issue of Sleep Medicine). “Insomnia is often characterized by physiologic hyperarousal, which may account for the relationship between poor sleep and cardiovascular risk,” Dr Shechter explained. “Going forward, it will be interesting to examine whether this blue-light blocking approach can be useful for improving cardiovascular outcomes like hypertension in individuals with poor sleep.”

• For more on this topic see our articles Is too much artificial light at night making us sick? and Are we sleep-deprived or just darkness-deprived?

Consumer interest in sleep products is on the rise. For instance, according to a Datamonitor Consumer 2014 survey, “insomnia” was one of the top 4 most prominent health issues for European consumers after tiredness/fatigue and stress (all of which are related to sleep). The survey showed sleep debt was a particular worry for middle-aged women.

As concerns about sleep rise, so has the international market for sleep-aids which is reported to be growing exponentially in many countries, according to Euromonitor International.

Natural products and dietary supplements – including melatonin, chamomile, valerian root, L-theanine, hops, lemon balm extract, and passion flower extract – only occupy a small portion of that market. This is in spite of the fact that market research data​ have repeatedly shown consumers prefer a natural alternative to synthetic OTC products.

Better sleep quality

The new study journal Complementary Therapies in Medicine​​  looked at 60 people who were randomly assigned to receive either 400 mg per day of chamomile (Matricaria recutita​) extract or a placebo (wheat flour) for 28 consecutive days. The average age of the participants was 70.

The data showed that, while the sleep quality in both groups was low at the start of the study, 28 days of supplementation with the chamomile extract significantly improved sleep quality, compared to the placebo group.

However, the chamomile extract did not lead to more (longer) sleep, which the researchers said may be linked to the short intervention period.

Tranquilizing effects

Commenting on the potential bioactives and mechanism(s) of action, the researchers wrote: “Chamomile extract includes different components such as apigenin, apigetrin, chamazulene, bisabolol, and farensen, of which, apigenin (a water-soluble component) binds benzodiazepine sites and causes tranquilizing effects in the central nervous system”​

They concluded: “The use of chamomile extract can significantly improve sleep quality among elderly people. Thus, it can be used as a safe modality for promoting elderly people’s sleep.”​

“The findings of this study show that the use of chamomile extract can significantly improve sleep quality among elderly people,” wrote the researchers.

Given the high prevalence of sleep disturbances among older people and the adverse effects of hypnotic medications, the experts say that their data shows that chamomile extract can be used as a safe way of promoting sleep.

Montmorency tart cherry juice was found to help extend sleep time by 84 minutes among eight study participants, ages 50 and older who suffer from insomnia, according to a new pilot study

The research, published in American Journal of Therapeutics involved 80 healthy people, aged 50 years or older with chronic insomnia and a usual bedtime between 9 p.m. and midnight. The researchers defined insomnia was defined as trouble sleeping on average three nights per week,

“Insomnia is quite common among older adults and it can lead to a range of health issues if left untreated,” said lead researcher Jack Losso, professor in the School of Nutrition and Food Sciences at Louisiana State University  in Baton Rouge, who has conducted previous studies on tart cherry juice and sleep. “However, many people are hesitant to resort to medications to help them sleep. That’s why natural sleep remedies are increasingly of interest and in demand.”

A natural source of melatonin and more

Tart cherry juice is known to be a natural source of melatonin, a hormone that our bodies need to induce sleep, and has been shown in previous studies to aid sleep. Cherries are also rich in antioxidant procyanidins and anthocyanins which may also be of benefit. Montmorency cherries are a type of tart cherry popular in the US.

Participants were randomly assigned to either a Montmorency tart cherry juice group or a placebo control group. Those in the Montmorency tart cherry juice group consumed about 240 ml (8 ounces) of the tart cherry juice containing a measured level of procyanidins in the morning and at night, 1-2 hours before bedtime, for 14 days.

Those in the placebo group were given a drink made of distilled water, fructose, dextrose and lemon powder, which did not contain the polyphenols found in the tart cherry juice.

After two weeks participants had an overnight polysomnographic sleep study and blood tests were also used to determine what is called the kynurenine-to-tryptophan ratio, which identifies tryptophan degradation and prostaglandin E2 (PGE2) to evaluate inflammation.

Participants were also questioned about how well they slept and after a two-week ‘washout period’, the groups swapped drinks and repeated the process again.

84 extra minutes in bed

This is the first time scientists have used polysomnographic equipment to study the impact that tart cherries have on sleep. What they found was that, compared to the placebo, the tart cherry juice was found to significantly extend sleep time of the participants by 84 minutes.

The kynurenine-to-tryptophan ratio changed too, showing reduced blood levels of kynurenine but increased tryptophan levels.

They also concluded that the procyanidins had an effect on sleep; for instance lab tests showed that the procyanidin B-2 in the cherry juice inhibited a substance called indoleanmine 2,3-dioxygenase (IDO), higher levels of which are associated with sleep difficulties as well as lowering levels of PGE2, which is a biomarker of inflammation.

This data adds to the growing body of previous research showing a range of benefits for tart cherry juice. For example, in 2016 researchers at from Northumbria University found that drinking tart Montmorency cherry juice significantly reduced high blood pressure at a level comparable to that achieved by drugs, according to new research.

Insufficient sleep a significant public health concern. In the US The Centers for Disease Control and Prevention (CDC) estimate that 50 to 70 million people in the United States have a sleep or wakefulness disorder.

Previous research showed having a purpose in life generally improves overall sleep when measured at a single point in time.

What researchers from the Northwestern University Feinberg School of Medicine in Chicago, IL, wanted to know was whether this was also true over a longer period of time. They set out to examine the link between having a sense of purpose in one’s life and the quality of one’s sleep.

Their findings are published in the journal Sleep Science and Practice.

What keeps us awake

Specifically, they looked at the association between having a sense of meaning and the likelihood of developing sleep apnea and restless leg syndrome (RLS).

Sleep apnea is a common disorder that increases with age in which a person has shallow breathing or pauses in breathing during sleep several times per hour. This disruption often makes a person feel unrefreshed upon waking up and excessively sleepy during the day.

Restless leg syndrome  causes uncomfortable sensations in the legs and an irresistible urge to move them. Symptoms commonly occur in the late afternoon or evening hours and are often most severe at night when a person is resting, such as sitting or lying in bed.

The researchers examined 825 individuals aged between 60 and 100 years, 77% of whom were female and over half of whom were African American.

The participants were asked a series of questions designed to evaluate the quality of their sleep and check for potential symptoms of RLS, as well as for symptoms of random eye movement behaviour disorder.

They were asked a further series of questions designed to evaluate their sense of purpose in life.

Having got the necessary background the participants were then followed for 2 years with regular assessments.

Drug free therapy

The study revealed that people who felt a sense of purpose had a 63% lower chance of developing sleep apnea and a 52% lower risk of RLS.

Additionally, the researchers found that overall, those with a higher sense of purpose had “moderately better” sleep quality. The results were largely the same across African American and white American study participants, so the findings have important implications for the US at large.

“Helping people cultivate a purpose in life could be an effective drug-free strategy to improve sleep quality, particularly for a population that is facing more insomnia,” said senior author Jason Ong, an associate professor of neurology at Northwestern University Feinberg School of Medicine. “Purpose in life is something that can be cultivated and enhanced through mindfulness therapies.”

It can also be cultivated through building stronger community relationships and through activities such as volunteering or, for older people, continuing useful work beyond retirement age.

Although the participants in the study were older, researchers said the findings are likely applicable to the broader public as well.

The analysis comprised data from 1,863 participants who took part in the Multi-Ethnic Study of Atherosclerosis (MESA) and who also enrolled in both MESA’s Sleep and Air Pollution studies.

The researchers looked at two of the most common air pollutants: NO₂ (nitrogen dioxide, a traffic-related pollutant gas) and PM_2.5, (fine-particle pollution).

Taking measurements

The researchers combined data from different sources. Air pollution measurements were gathered from hundreds of MESA Air and Environmental Protection Agency monitoring sites in six US cities. This allowed the team to estimate air pollution exposures at each participant’s home at two time points: one year and five years.

Wrist actigraphy, which measures small movements, provided detailed estimates of sleep and wake patterns over seven consecutive days. This was used to calculate “sleep efficiency”- a measure of the percentage of time in bed spent asleep vs. awake.

The population was divided into four groups according to levels of pollution and sleep efficiency was measured against varying levels of pollution exposure.

Results which were presented ahead of publication at the recent ATS 2017 International Conference found:

• The group with the highest levels of NO₂ over five years had an almost 60% increased likelihood of having low sleep efficiency compared to those with the lowest NO₂
• The group with the highest exposures to small particulates (PM_2.5) had a nearly 50% increased likelihood of having low sleep efficiency.

Chronic effects

This study was particularly looking at in chronic exposure to air pollution and what that long-term exposure might mean for sleep health, but the researchers admit that there may also be acute sleep effects from short-term exposure to high pollution levels as well.

“These new findings indicate the possibility that commonly experienced levels of air pollution not only affect heart and lung disease, but also sleep quality.” said lead author Martha E. Billings, MD, MSc, assistant professor of medicine at the University of Washington.

She said one likely reason for this effect is that air pollution causes upper airway irritation, swelling and congestion, and may also affect the central nervous system and brain areas that control breathing patterns and sleep.

“Improving air quality may be one way to enhance sleep health and perhaps reduce health disparities,” she added.

• We can’t control the quality of outdoor air, though studies show plant power can help, see Plants are the best ‘green technology’ for reducing city pollution
• For ways to improve indoor air quality see our articles House plants – a natural way to improve indoor air quality and A cleaner, greener home – without chemicals!
• See also tips for How to get a good night’s sleep

• For more on this topic see our article Chronomedicine – natural cycles that rule our health

The pattern of cutting back on sleep during the work week followed by catching up on sleep over the weekend is common. Even short-term sleep restriction, with four or five hours of sleep per night, can increase the risk of developing diabetes by about 16% – comparable to the increase in risk caused by obesity.

The finding, based on a study performed at the University of Chicago sleep laboratory, published online in the journal Diabetes Care, could have implications for the large numbers of people who work long hours.

“We found that two long nights spent catching up on lost sleep can reverse the negative metabolic effects of four consecutive nights of restricted sleep,” said study author Josiane Broussard, PhD, an assistant research professor in the Department of Integrative Physiology at the University of Colorado, Boulder.

Insulin impacts

For this small study the researchers recruited 19 volunteers, all healthy young men. The men’s sleeping patterns were manipulated so that they were sleep deprived and then allowed 2 nights of extended sleep, during which they averaged 9.7 hours of sleep.

Investigators then tested the subjects’ insulin sensitivity – the ability of insulin to regulate blood sugars – and the ‘disposition index’, which measures insulin secretion, a predictor of diabetes risk. After four nights of sleep restriction, the volunteers’ insulin sensitivity decreased by 23% and their diabetes risk increased by 16%.

After two nights of extended sleep, however, insulin sensitivity and the risk of diabetes returned to normal sleep levels.

More risks of sleep deprivation

The researchers admit their study is too small to be definitive – and of course, only involved healthy men – but the results point the way towards more comprehensive research in the future.

“The metabolic response to this extra sleep was very interesting and encouraging,” said senior co-author Esra Tasali, MD, associate professor of medicine at the University of Chicago. “It shows that young, healthy people who sporadically fail to get sufficient sleep during the work week can reduce their diabetes risk if they catch up on sleep during the weekend.”

Increased risk of developing diabetes is not the only drawback associated with inadequate sleep. Chronically sleep deprived people are more likely to make poor food choices, and develop other health problems such as increased inflammation and high blood pressure.

They also show cognitive problems, tend to be less alert and have difficulty concentrating, reasoning and solving problems. They are prone to traffic accidents. It is possible that getting more catch-up sleep could also have a beneficial impact on these problems.

• Having trouble sleeping? See our articles: How to get a good night’s sleep and A sleep solutions ‘cheat sheet’