Poor Sleep

Why Poor Sleep Might Be Early Sign of Alzheimer’s

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The cells which clear Alzheimer’s plaques from the brain follow a 24-hour circadian rhythm. By ART-ur/Shutterstock

The cells which clear Alzheimer’s plaques from the brain follow a 24-hour circadian rhythm.

A good night’s sleep has always been linked to better mood, and better health. Now, scientists have even more evidence of just how much sleep – and more specifically our circadian rhythm, which regulates our sleep cycle – is linked to certain diseases, such as Alzheimer’s disease. A team of researchers from the United States have found further evidence that the cells which help keep the brain healthy and prevent Alzheimer’s disease also follow a circadian rhythm.

Our circadian rhythm is a natural, internal process that follows a 24-hour cycle. It controls everything from sleep, digestion, appetite and even immunity. Things like outside light, when we eat our meals and physical activity all work to keep our circadian rhythm in sync. But even small things like staying up a bit later than normal, or even eating at a different time than we’re used to can knock this internal “clock” out of whack.

It’s important for our circadian rhythm to work properly, as disruption to this cycle is linked to a number of health problems, including mental health disorders, cancer, and Alzheimer’s.

Research shows that for patients with Alzheimer’s disease, circadian rhythm disruptions are usually seen as changes in a patient’s sleep habits that happen long before the disorder fully manifests. This is something that gets worse in the later stages of the disease. However it’s not yet fully understood whether poor sleep causes Alzheimer’s, or if it happens as a result of the disease.

Brain Plaques

One thing researchers consistently find in the brains of people with Alzheimer’s disease is an accumulation of a protein called beta-amyloid. These proteins tend to clump together in the brain and form “plaques”. These plaques disrupt the function of the brain’s cells, which may in turn lead to cognitive issues, such as memory loss. In normal brains, the protein is cleaned up before it has the chance to cause issues.

This latest study has now shown that the cells responsible for clearing up beta-amyloid plaques – and keeping the brain healthy – also follow a 24-hour circadian rhythm. This could mean that if the circadian rhythm is disrupted it could make it more difficult for these cells to remove the harmful plaques that are linked to Alzheimer’s.

A silhouetted outline of a person's head, with a clock in the centre to illustrate the 24-hour circadian rhythm.
The circadian rhythm is a natural, 24-hour cycle that controls many of the body’s processes.

To conduct their research, the team looked specifically at macrophages. These are immune cells that exist throughout the body, including in the brain. Macrophages essentially eat up anything (such bacteria, or even proteins that haven’t formed correctly) that might be considered a threat to the body.

To understand whether these immune cells follow a circadian rhythm, the researchers used macrophages from mice and grew them in the lab. When they fed the cells with beta-amyloid, they found that the ability of the macrophages to eliminate beta-amyloid changed throughout a 24-hour period.

They also found that specific proteins on the surface of the macrophages – called proteoglycans – have a similar circadian rhythm throughout the day. In fact, they found that when the amount of proteoglycans were at their lowest levels, beta-amyloid clearance was at its highest. So when the macrophages have a lot of these proteins, they don’t clear beta-amyloid as well. They also found that when the cells lost their natural circadian rhythm, they didn’t clear beta-amyloid as normal.

Although this study used mouse macrophages that weren’t brain specific, other studies have shown that microglia – the brain’s immune cells (which are also one type of brain macrophages) – also have a circadian clock. This circadian clock regulates everything from the function and morphology of microglia to its immune response. It’s possible that microglial circadian rhythm may also even be involved in the control of neuronal connectivity – which eventually might contribute to the worsening of Alzheimer’s-related symptoms, or even sleep issues that older people might exhibit.

But in studies that have looked at full organisms (such as mice) instead of only cells, the results about the relationship between Alzheimer’s and circadian rhythm are more conflicting – they often fail to portray all the issues found in humans with Alzheimer’s disease, as they only study specific systems or proteins that might be affected by Alzheimer’s disease. This means they aren’t a fully accurate representation of how Alzheimer’s occurs in humans.

In studies that looked at people with Alzheimer’s, researchers have found that circadian rhythm dysfunction has worsened as the disease progressed. Other research also showed that this circadian rhythm disruption was linked with sleep problems and Alzheimer’s disease, alongside the brain being less able to clear brain “garbage” (including beta-amyloid) – which may further contribute to memory problems. But it’s difficult to say whether circadian rhythm disruption (and the problems it causes) happened as a result of Alzheimer’s disease, or if they were part of the cause.

Should the findings of this study be replicated in humans, this could bring us one step closer to understanding one of the ways in which our circadian rhythm is linked to Alzheimer’s disease. Nevertheless, it’s widely agreed that sleep is important for many aspects of our health. So protecting your circadian rhythm is not just good for your brain – but for your overall health.

Poor sleep may undermine people’s attempts to keep weight off.

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Randomised trial finds poor sleeping habits may contribute to regaining weight after weight loss in adults with obesity.

New research being presented at this year’s European Congress on Obesity (ECO) in Maastricht, Netherlands (4-7 May), finds that not getting enough good quality sleep undermines people’s attempts to keep weight off after dieting, and suggests that around two hours of vigorous physical activity per week can help maintain better sleep.

The study is by medical student Adrian F. Bogh, Professor Signe S. Torekov and PhD student Simon B. K. Jensen from the University of Copenhagen, Denmark and colleagues.

“It was surprising to see how losing weight in adults with obesity improved sleep duration and quality in such a short time, and how exercising while attempting to keep the weight off preserved improvements in sleep quality”, says Bogh. “Also, it was intriguing that adults who aren’t sleeping enough or getting poor quality sleep after weight loss appear less successful at maintaining weight loss than those with sufficient sleep.”

More than a third of adults in the UK [1] and the USA [2] don’t get enough sleep on a regular basis (defined as less than 6 or 7 hours per night, respectively), due to host of aspects of modern life including stress, computers, smart devices, and the blurring of work life boundaries.

Not getting enough sleep or getting poor quality sleep increases risks for high blood pressure, high cholesterol and atherosclerosis (fatty deposits building up in arteries). Not getting enough sleep is linked to obesity, diabetes and inflammation, all of which can worsen cardiovascular disease. Sleeping too much or too little also has been shown to increase the risk of stroke, heart attack and death. It has been suggested that sleep habits may be a contributing factor in weight regain after a weight loss.

For this study, researchers analysed data from the S-LiTE randomised placebo-controlled trial to investigate changes in sleep duration and quality during diet-induced weight loss. In total, 195 adults (age 18 to 65 years) with obesity (body mass index [BMI] 32 to 43 kg/m2) followed a very low-calorie diet (800 kcal/day) for eight weeks and lost an average of 12% of their body weight (figure 2 in poster).

Participants were then randomly assigned to one year of weight loss maintenance with either: daily injection of placebo (49 participants), daily 3mg injection of the weight-loss drug liraglutide (49), four exercise sessions per week (48), or a combination of both treatments (49).  Everyone in the exercise groups were encouraged to participate in supervised 45-minute sessions, twice a week, doing spinning and circuit training, and two unsupervised sessions of 30 minutes.

Sleep duration was measured using data from accelerometers worn by study participants before and after the low-calorie diet and after 13, 26 and 52 weeks of weight maintenance. Sleep quality was subjectively measured with the Pittsburgh Sleep Quality Index (PSQI), a self-rated questionnaire. Lower scores on the PSQI indicate better quality sleep, ranging from 0 for the best sleep to 21 as the worst possible sleep. Scores greater than five are considered poor quality sleep.

To examine the association between sleep and weight gain, participants were grouped according to their average sleep duration (below/above 6 hrs/night) or sleep quality (below/above a PSQI score of 5) at randomisation (after low-calorie diet).

The researchers found that following the 8-week low-calorie diet, sleep quality and sleep duration improved in all participants. Notably, after one year of weight maintenance, participants in the exercise groups maintained self-reported sleep quality improvements achieved from the low-calorie diet, while non-exercise groups relapsed (average between group difference 1 PSQI score point).

Liraglutide treatment had no significant effect on any sleep quality or duration compared to placebo.


The analyses also showed that participants who slept on average less than 6 hours per night at the start of the study increased their BMI by 1.3 kg/m2 during the 1-year weight maintenance phase compared to longer sleepers (over 6 hours per night).

Similarly, poor sleepers (PSQI score 5 or higher) at the start of the study increased their BMI by 1.2 kg/m2 during the weight maintenance phase, compared to good sleepers (PSQI score less than 5).

“The fact that sleep health was so strongly related to weight loss maintenance is important since many of us don’t get the recommended amount of sleep needed for optimal health and functioning,” says Professor Torekov. “Future research examining possible ways of improving sleep in adults with obesity will be an important next step to limit weight regain. Weight loss maintained with exercise seems promising in improving sleep”

Despite the important findings, the authors note that the study is observational and cannot prove that poor sleep causes weight changes, but suggests that it is likely to contribute.

Source:www.eurekalert.org

Poor sleep hinders attempts to maintain weight loss

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Adults with obesity who lost weight while dieting struggled to maintain their weight loss if they slept less than 6 hours per night, according to findings presented at the European Congress on Obesity.

Adrian F. Bogh, a medical student at the University of Copenhagen, and colleagues also found that exercise during weight loss maintenance may help preserve sleep quality but not duration.

Overweight patient and doctor
Adults with obesity struggled to maintain their weight loss if they slept less than 6 hours per night. Source: Adobe Stock.

In a randomized, placebo-controlled, two-by-two factorial study, Bogh and colleagues evaluated 195 adults with obesity (BMI, 32 to 43 kg/m²). During an 8-week, low-calorie diet period, the participants lost an average of 12% body weight. The participants were then randomly assigned to 1 year of weight loss maintenance with placebo; exercise (4 times per week) and placebo; Saxenda 3 mg (liraglutide, Novo Nordisk) daily; or exercise and liraglutide.

The researchers measured participants’ sleep duration and efficiency with accelerometers and the Pittsburgh Sleep Quality Index (PSQI) before the diet period, after the diet period (baseline) and after 26 and 52 weeks of maintenance. A global score of five or more on the PSQI was considered poor sleep and less than five was good sleep.

Overall, sleep quality, efficiency and duration increased for all participants after the diet period. However, participants who got less than 6 hours of sleep per night at baseline increased their BMI by an average of 1.3 kg/m² (P = .02) by week 52 compared with participants who slept 6 to 7 hours each night, according to Bogh and colleagues. Moreover, poor sleepers at baseline increased their BMI by 1.2 kg/m² (P = .01) compared with good sleepers.

Participants who were randomly assigned to some or only exercise maintenance achieved sustained sleep quality improvements from diet by one global score point (P = .02), the researchers reported. Maintenance with liraglutide had no significant effect on any sleep measure.

“It was surprising to see how losing weight in adults with obesity improved sleep duration and quality in such a short time, and how exercising while attempting to keep the weight of preserved improvements in sleep quality,” Bogh said in a press release. “Also, it was intriguing that adults who aren’t sleeping enough or getting poor quality sleep after weight loss appear less successful at maintaining weight loss than those with sufficient sleep.”

Signe S. Torekov, MSc, PhD, a professor in the department of biomedical sciences at the University of Copenhagen, added that the findings demonstrate the importance of sleep “since many of us don’t get the recommended amount of sleep needed for optimal health and functioning.”

“Future research examining possible ways of improving sleep in adults with obesity will be an important next step to limit weight regain,” she said. “Weight loss maintained with exercise seems promising in improving sleep.”

References:

Bogh A, et al. Presentation PO3.26. Presented at: European Congress on Obesity; May 4-7, 2022; Maastricht, Netherlands.

The Connections Between Sugar, Poor Sleep, and Diabetes

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If you have diabetes, you already know that you need to keep a very close eye on how much sugar you eat. It’s the one food that most reliably raises blood sugar, and it is highly associated with obesity, to boot.

What may be less obvious is the link between sugar consumption and sleep quality.

Sleep is surprisingly important for people with diabetes: poor sleep increases insulin resistance and, when chronic, is associated with all sorts of negative health outcomes. A bad night of sleep also seems to make us crave sugary junk food – exactly the food that just makes diabetes even tougher to manage.

A new study from Brigham Young University is just the latest of many to find that there is a very real connection between sugar intake and inadequate sleep. In this experiment, ninety-three adolescents were randomized to five consecutive nights of healthy sleep (9.5 hours “sleep opportunity”) or short sleep (6.5 hours); researchers then tracked what they ate.

The teens with less sleep – they averaged 2 hours and 20 minutes fewer – ended up eating more added sugar, more carbohydrates, more sweetened beverages, and fewer fruits and vegetables. Most of the difference between the two groups was attributed to late-night snacking. The study wasn’t designed to explain why the exhausted teens were snacking more, but its lead author speculated that “tired teens are looking for quick bursts of energy to keep them going until they can go to bed.”

Many other similar studies have been conducted, and have found that a lack of sleep both provokes you to overeat and to prefer higher-calorie foods.

There is also some evidence that poor sleep causes the metabolism to operate less efficiently. A small but thought-provoking 2010 study took 10 overweight adults and asked them to eat the same diet for two weeks. Half were told to sleep 5.5 hours per night, the other half 8.5 hours. Remarkably, the dieters that got plenty of sleep lost 55% more fat than the sleep-deprived group, suggesting that lack of sufficient sleep can really sabotage a weight loss effort.

It seems clear that a lack of sleep prompts people to make unhealthy food choices, and perhaps also to blunt the impact of good food choices. Does it work the opposite way, too? Does eating poorly reduce sleep quality?

Scientists appear to have paid somewhat less attention to this question. At least one study found diets with high saturated fat, low fiber, and high sugar were associated with light sleep and more frequent nocturnal arousal. The authors concluded that “it is possible that a diet rich in fiber, with reduced intake of sugars and other non-fiber carbohydrates, may be a useful tool to improve sleep depth and architecture in individuals with poor sleep.”

If it’s true that bad food leads to bad sleep, it suggests that there may be a vicious cycle at play – poor sleep causes us to reach for unhealthy foods, which just causes more poor sleep. For people with diabetes, this seems even more likely to be true, given the way that suboptimal eating choices can lead to nighttime glucose management problems.

There needs to be more study to tease out correlation from causation, and figure out if suboptimal sleep habits are causing suboptimal dieting habits, or vice versa, or both. But in the meantime, it must be unsurprising that so many surveys of sleep habits and diets, whether they examine Danish school children or middle-aged Japanese women, find that poor diets and poor sleep go hand in hand.

Poor Sleep and High Blood Sugar

Of course, people with diabetes always have to be thinking about their blood sugar, too. High blood sugar – a direct result of sugar consumption – is also correlated with poor sleep, even in people without diabetes. Poor sleep habits interrupt a complex range of hormonal and metabolic changes, resulting in increased inflammation and insulin resistance, both of which can help cause high blood sugar.

The causation appears to go in both directions here, too, as high blood sugar and insulin resistance are thought to contribute to common sleep problems such as sleep apnea and sleep-disordered breathing.

According to the experts at the National Institute of Diabetes and Digestive and Kidney Diseases, there is little direct evidence as of yet that improving sleep can lead directly to improved glucose metabolism. But the subject has lately become an area of intense interest: “the efficacy and effectiveness of interventions that optimize sleep and circadian function to prevent the development or reduce the severity of these metabolic disorders need to be urgently evaluated.”

Takeaways

There is a great deal of evidence linking poor sleep habits with poor diet and with suboptimal metabolic function, although the details of the interactions are not always clear. Many studies show that poor diet is associated with lack of quality sleep, and that lack of quality sleep is associated with insulin resistance and diabetes risk factors.

If you’re trying to optimize your diabetes management, don’t forget about sleep! It’s just one more reason to lay off the sugar today. And a night without enough sleep might make it more likely for you to reach for sweet junky food tomorrow, which might just make it less likely that you’ll get enough sleep tomorrow night, sparking an unhealthy cycle.

Poor Sleep May Heighten Alzheimer’s Risk

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Older adults who are sleepy during the day might have harmful plaque building in their brain that is a sign of impending Alzheimer’s disease, researchers report.

A hallmark of Alzheimer’s is the accumulation of a protein in the brain called beta-amyloid. It’s believed that one benefit of sleep is to clear beta-amyloid, and poor sleep might allow it to build up, the authors of the new study pointed out.

“Elderly individuals with excessive daytime sleepiness may be more vulnerable to Alzheimer’s disease-related changes,” said corresponding author Prashanthi Vemuri, an associate professor of radiology at the Mayo Clinic in Rochester, Minn.

Vemuri noted that the new study is only observational and as such does not prove that poor sleep causes an increase in beta-amyloid.

The association, however, is so strong that a link between sleep and beta-amyloid probably exists, but exactly what that link may be isn’t clear, she added.

It’s also unclear how much poor sleep it takes to increase beta-amyloid accumulation, the researchers said.

Although beta-amyloid buildup is a sign of Alzheimer’s, it doesn’t doom one to the disease, and might only be a sign of other aging processes, Vemuri suggested.

“Sleep has been proposed to be important for clearance of brain amyloid,” she said. “This study affirms that disrupted sleep may be a risk factor for Alzheimer’s disease via increased amyloid.”

Vemuri’s team studied nearly 300 people aged 70 and older who didn’t suffer from dementia. About 22 percent reported having excessive daytime sleepiness when the study began.

Study participants completed a survey about sleep and had at least two brain scans between 2009 and 2016.

The researchers compared the scans in search of changes in the brain. They found increased beta-amyloids in key brain areas in participants who reported being very sleepy during the day.

The study was published online March 12 in the journal JAMA Neurology.

The co-author of an accompanying journal editorial said consistent and untreated sleep disturbance appears to aid Alzheimer’s progression and it can happen early, before any symptoms are seen.

“These findings, however, further support the idea that sleep is critical for mental health, and that chronically disturbed sleep may facilitate the development of Alzheimer’s disease or accelerate its progression,” said Bryce Mander. He’s an assistant professor of psychiatry and human behavior at the University of California, Irvine School of Medicine.

This is another reason you should talk to your doctor if you have sleep problems, because many are treatable, Mander said.

Researchers now need to study whether treating sleep disturbances reduces plaque buildup, he added.

“We know very little about how sleep treatments can impact Alzheimer’s disease risk and progression,” Mander said. “It is really important that we, as a society, fund and conduct the studies necessary to find out.”