A Good Night’s Sleep Recharges Immune System

If you want to stay well, make sure you’re getting enough sleep.

That’s the conclusion of a new study that found that good sleep helps regulate a key component of the body’s immune system.

Specifically, it influences the environment where white blood cells known as monocytes form, develop and get ready to support the immune function, a process called hematopoiesis.

“What we are learning is that sleep modulates the production of cells that are the protagonists – the main actors – of inflammation,” said senior study author Filip Swirski, director of the Cardiovascular Research Institute at Icahn School of Medicine at Mount Sinai, in New York City. “Good quality sleep reduces that inflammatory burden.”

The researchers studied the impact of sleep in a clinical trial of 14 adults. Each participant was assigned to get either 7.5 hours of sleep each night for six weeks or to get about six hours of sleep each night. Then they had six weeks of a “wash-out” period where they got their normal amount of sleep before being assigned to the opposite schedule for another six weeks.

The researchers collected morning and afternoon blood samples in the fifth and sixth weeks of both parts of the study.

What did they find? When the adults did not get enough sleep, they had higher levels of circulating monocytes in the afternoon, higher numbers of immune stem cells in the blood, and evidence of immune activation.

“The stem cells have been imprinted, or genetically altered, under the influence of sleep restriction,” Swirski said. “The change isn’t permanent, but they continue to self-replicate at a higher rate for weeks.”

This higher production of immune cells can speed the development of an age-related condition known as clonal hematopoiesis, which in turn is linked to an increased risk of cardiovascular disease.

The study, published in the Journal of Experimental Medicine, was funded by the U.S. National Institutes of Health (NIH).

“Sleep impacts optimal functioning of nearly every cell and organ in the body,” said Marishka Brown, director of the National Center on Sleep Disorders Research at the NIH. “The mechanistic insight from this study supports findings from larger population studies, which have shown that sleep can have a protective effect against a variety of conditions, including heart disease, cancer and dementia.”

Establishing sound sleep patterns early in life is important, the study authors said in an institute news release. Doing so may reduce the severity of inflammatory conditions, such as sepsis.

An adequate night’s sleep for most adults is seven to eight hours of uninterrupted sleep each night. Older adults need about seven to nine hours. Children aged 11 to 17 should get about eight to 10 hours nightly.

Source: HealthDay





Study: Poor Sleep Can Make Folks Selfish

The health risks of losing sleep are well known, ranging from heart disease to depression, but who knew that too little sleep can also make you selfish?

That’s the takeaway of new research from the University of California, Berkeley.

“This new work demonstrates that a lack of sleep not only damages the health of an individual, but degrades social interactions between individuals and, furthermore, degrades the very fabric of human society itself,” said Matthew Walker, director of the university’s Center for Human Sleep Science. “How we operate as a social species — and we are a social species — seems profoundly dependent on how much sleep we are getting.”

Walker and co-author Eti Ben Simon, a postdoctoral fellow in psychology, noted that a growing number of studies, including this one, show that sleep loss compromises bonds between individuals — and even the altruistic behavior of nations.

“If you’re not getting enough sleep, it doesn’t just hurt your own well-being, it hurts the well-being of your entire social circle, including strangers,” Ben Simon said.

In a research review published online in PLOS Biology, the researchers described three separate studies that gauged the impact of sleep on people’s willingness to help others.

In one, 24 healthy volunteers underwent brain scans after eight hours of sleep and also after a sleepless night. The functional MRI scan revealed that brain areas involved in empathy and trying to understand others’ wants and needs were less active after a sleepless night.

“When we think about other people, this [theory of mind] network engages and allows us to comprehend what other person’s needs are: What are they thinking about? Are they in pain? Do they need help?” Ben Simon said. “However, this network was markedly impaired when individuals were sleep deprived. It’s as though these parts of the brain fail to respond when we are trying to interact with other people after not getting enough sleep.”

Another study tracked more than 100 people online for three or four nights, measuring how long they slept and how many times they woke. Then it gauged their desire to hold an elevator door open for someone else or help an injured stranger on the street, among other scenarios.

“Here, we found that a decrease in the quality of someone’s sleep from one night to the next predicted a significant decrease in the desire to help other people from one subsequent day to the next,” Ben Simon said. “Those with poor sleep the night prior were the ones that reported being less willing and keen to help others the following day.”

And, finally, a database of 3 million charitable donations in the United States between 2001 and 2016 showed giving dropped after the seasonal change to Daylight Saving Time. Donations fell 10% overall, but not in regions where the time doesn’t shift, the study authors reported.

“Even a very modest ‘dose’ of sleep deprivation — here, just the loss of one single hour of sleep opportunity linked to Daylight Saving Time — has a very measurable and very real impact on people’s generosity and, therefore, how we function as a connected society,” Walker said. “When people lose one hour of sleep, there’s a clear hit on our innate human kindness and our motivation to help other people in need.”

In an earlier study, Walker and Ben Simon found that sleep deprivation increased feelings of loneliness, caused people to isolate and, when they did interact with people, to spread their loneliness to others.

“Looking at the big picture, we’re starting to see that a lack of sleep results in a quite asocial and, from a helping perspective, anti-social individual, which has manifold consequences to how we live together as a social species,” Walker said. “A lack of sleep makes people less empathetic, less generous, more socially withdrawn, and it’s infectious — there is contagion of loneliness.”

Promoting sleep rather than shaming people for getting enough sleep could help shape social bonds, Ben Simon suggested. More than half of people in developed countries report not getting enough sleep.

“In these divisive times, if there was ever a need for a strong, prosocial lubricant to enable the very best version of ourselves within society, now seems to be it,” Walker said. “Sleep may be a wonderful ingredient that enables the alacrity of helping between human beings.”

Source: HealthDay





A Warming Planet Could Mess with Our Sleep – and Make Us More Vulnerable to Infectious Disease

It’s a scene that will be familiar for many after yet another scorching summer: You’re lying awake during a warm night, bedsheets kicked aside, an overmatched ceiling fan providing little respite as you struggle to get a good night’s sleep.

But a warming planet doesn’t just mean more people may find it harder to get quality sleep. There is also evidence suggesting that sleep disturbance could make it harder for the body to fend off infection, according to a new research paper from Dr. Michael Irwin, a professor of psychiatry and biobehavorial sciences at UCLA.

Irwin, who has extensively studied how sleep regulates the immune system, said while there are few studies on how ambient, or surrounding air, temperature affects sleep, they indicate that warmer temperatures contribute to sleep disturbance. Studies have also shown that poor sleep is associated with heightened risk of infectious disease and could make some vaccination less effective, Irwin writes in a research review published in the peer-reviewed journal Temperature.

Given research showing a potential link between poor sleep and reduced immune response, Irwin said this raises timely questions about whether climate change results in heightened infectious disease risk amid the ongoing COVID-19 pandemic, a monkeypox outbreak and the reemergence of the poliovirus in New York and London.

“No one has previously put together this notion that the ongoing climate crisis is contributing to sleep disturbance and that it’s possibly contributing to the altered risk of infectious disease we’re seeing,” said Irwin, the director of the Cousins Center for Psychoneuroimmunology at the Jane and Terry Semel Institute for Neuroscience and Human Behavior at UCLA.

Irwin said the issue also raises important implications about disparities, since low-income communities and communities of color face heightened risk from heat and have less access to air conditioning.

What the research shows

Irwin’s paper reviews how poor sleep affects the immune system and could make people more vulnerable to infectious disease threats. Among the research he cites:

  • There’s a strong association between sleep and thermoregulation, or how humans maintain a steady core internal temperature. Experimental studies have shown that reducing air temperatures to a range in which humans can maintain a normal body temperature without expending excess energy improves sleep quality, while increases in air temperature result in increased wakefulness. Survey data of 765,000 people in the United States also found increases in nighttime temperatures amplified self-reported nights of insufficient sleep, with the largest effects during the summer and among lower-income and elderly people.
  • It’s thought that sleep helps prepare the body’s response to possible injury or infection that could occur the following day. When sleep is disrupted, that contributes to increases in inflammation and dampens the body’s ability to fight off infections. That means there may be heightened risk among older adults and patients with inflammatory disorders, like cardiovascular disease and some types of depression, who have higher prevalence of insomnia.
  • Some small experimental studies in humans indicate that poor sleep could also result in poorer vaccine response. In one study, for instance, people who had four straight nights of partial sleep deprivation before receiving a trivalent influenza vaccine had a 50% reduction in antibody titers compared to those with normal sleep. Other studies that tested the effects of sleep disruption after influenza or hepatitis vaccination suggest that short sleep duration, at least in healthy adults, is likely associated with a reduced adaptive immunologic response and possibly clinical protection.
  • Sleep duration is also associated with infectious disease risk outcomes. Basic research has shown that longer sleep leads to decreases in bacterial load and improved survival in a variety of infectious disease models. Self-reported surveys have also shown an association between shorter sleep and higher infection risk.
  • While there’s abundant evidence that sleep disturbance and depressive symptoms have greatly increased during the COVID-19 pandemic, there’s little known about how poor sleep may be affecting risk of COVID-19 infection and outcomes. However, a recent study of over 46,000 patients indicated that a significant sleep disturbance was associated with an over 2-fold increase in the mortality risk for patients who had COVID-19, while no similar association was found in those who did not.

Irwin said that future research on this topic should evaluate how altering ambient temperatures affects sleep and, as a result, immune function. He said there should also be a focus on how rising ambient temperatures may be affecting diverse and disadvantaged communities.

“Just like the pandemic is impacting socioeconomically disadvantaged and ethnic groups disproportionately with more morbid outcomes, it might be that increase in ambient temperature we’re seeing are further exaggerating those risk profiles,” Irwin said.

Source: UCLA Health





Study of Sleep in Older Adults Suggests Nixing Naps, Striving for 7-9 hours a Night

Laura Williamson wrote . . . . . . . . .

Napping, as well as sleeping too much or too little or having poor sleep patterns, appears to increase the risk for cardiovascular disease in older adults, new research shows.

The study, published Tuesday in the Journal of the American Heart Association, adds to a growing body of evidence supporting sleep’s importance to good health. The American Heart Association recently added sleep duration to its checklist of health and lifestyle factors for cardiovascular health, known as Life’s Essential 8. It says adults should average seven to nine hours of sleep a night.

“Good sleep behavior is essential to preserve cardiovascular health in middle-aged and older adults,” said lead author Weili Xu, a senior researcher at the Aging Research Center in the department of neurobiology, care sciences and society at the Karolinska Institute in Stockholm, Sweden. “We encourage people to keep nighttime sleeping between seven to nine hours and to avoid frequent or excessive napping.”

Prior research has shown poor sleep may put people at higher risk for a range of chronic illnesses and conditions affecting heart and brain health. These include cardiovascular disease, dementia, diabetes, high blood pressure and obesity. According to the Centers for Disease Control and Prevention, nearly 35% of U.S. adults say they get less than seven hours of sleep, while 3.6% say they get 10 or more hours.

Previous sleep duration studies show that sleeping too much or too little both may raise the risk for cardiovascular disease. But whether napping is good or bad has been unclear.

In the new study, researchers analyzed sleep patterns for 12,268 adults in the Swedish Twin Registry. Participants were an average of 70 years old at the start of the study, with no history of major cardiovascular events.

A questionnaire was used to collect data on nighttime sleep duration; daytime napping; daytime sleepiness; the degree to which they considered themselves a night person or morning person, based on the time of day they considered themselves most alert; and symptoms of sleep disorders, such as snoring and insomnia. Participants were followed for up to 18 years to track whether they developed any major cardiovascular problems, including heart disease and stroke.

People who reported sleeping between seven and nine hours each night were least likely to develop cardiovascular disease, a finding in keeping with prior research. Compared with that group, those who reported less than seven hours were 14% more likely to develop cardiovascular disease, and those who reported more than 10 hours were 10% more likely to develop cardiovascular disease.

Compared with people who said they never napped, those who reported napping up to 30 minutes were 11% more likely to develop cardiovascular disease. The risk increased by 23% if naps lasted longer than 30 minutes. Overall, those who reported poor sleep patterns or other sleep issues – including insomnia, heavy snoring, getting too much or too little sleep, frequent daytime sleepiness and considering themselves a night person – had a 22% higher risk

Study participants who reported less than seven hours of sleep at night and napping more than 30 minutes each day had the highest risk for cardiovascular disease – 47% higher than those reporting the optimal amount of sleep and no naps.

The jury is still out on whether naps affect cardiovascular risk across the lifespan, said Marie-Pierre St-Onge, center director for the Sleep Center of Excellence and an associate professor at Columbia University in New York City. She noted that the new research, which she was not involved in, was restricted to older adults.

Rather than trying to recoup sleep time by napping, people should try to develop healthier sleep habits that allow them to get an optimal amount of sleep at night, St-Onge said. This includes making sure the sleep environment is not too hot or cold or too noisy. Reducing exposure to bright light before going to sleep, not eating too late at night, getting enough exercise during the day and eating a healthful diet also help.

“Even if sleep is lost during the night, excessive napping is not suggested during the day,” Xu said. And, if people have persistent trouble getting enough sleep, they should consult a health care professional to figure out why, she said.

Source: American Heart Association





American Heart Association Adds Sleep to Cardiovascular Health Checklist

Sleep duration is now considered an essential component for ideal heart and brain health. Life’s Essential 8™ cardiovascular health score replaces Life’s Simple 7™, according to a new Presidential Advisory, Life’s Essential 8—Updating and Enhancing the American Heart Association’s Construct on Cardiovascular Health, published today in Circulation, the Association’s flagship, peer-reviewed journal.

Other updates to the measures of optimal cardiovascular health, now for anyone ages 2 and older, include a new guide to assess diet; accounting for exposure to secondhand smoke and vaping; using non-HDL cholesterol instead of total cholesterol to measure blood lipids; and expanding the blood sugar measure to include hemoglobin A1c, a key measure to assess Type 2 diabetes risk.

Cardiovascular disease is the number one cause of death in the U.S. and globally. According to the Association’s 2022 Heart Disease and Stroke Statistics Update, approximately 121.5 million people in the U.S. have high blood pressure, 100 million have obesity, more than 28 million people have Type 2 diabetes, and only 1 in 4 adults reported achieving the physical activity and exercise recommended in the U.S. Department of Health and Human Services’ Physical Activity Guidelines for Americans, 2nd edition. Various research studies over the past two decades indicate more than 80% of all cardiovascular events may be prevented by healthy lifestyle and management of known cardiovascular risk factors.

“The new metric of sleep duration reflects the latest research findings: sleep impacts overall health, and people who have healthier sleep patterns manage health factors such as weight, blood pressure or risk for Type 2 diabetes more effectively,” said American Heart Association President Donald M. Lloyd-Jones, M.D., Sc.M., FAHA, who led the advisory writing group and is chair of the department of preventive medicine, the Eileen M. Foell Professor of Heart Research and professor of preventive medicine, medicine and pediatrics at Northwestern University’s Feinberg School of Medicine in Chicago. “In addition, advances in ways to measure sleep, such as with wearable devices, now offer people the ability to reliably and routinely monitor their sleep habits at home.”

The Association first defined the 7 metrics for cardiovascular health in 2010 to identify the specific health behaviors and health factors that drive optimal heart and brain health. Brain health in relation to cardiovascular health was defined in a 2017 American Heart Association Presidential Advisory. It was further acknowledged as an important component of optimal cardiovascular health in the Association’s January 2021 Scientific Statement on the mind-heart-body connection. Findings from both papers are incorporated into Life’s Essential 8™.

After 12 years and more than 2,400 scientific papers on the topic, new discoveries in heart and brain health and in the ways to measure cardiovascular health provided an opportunity to revisit each health component in more detail. Four of the original metrics have been redefined for consistency with newer clinical guidelines or compatibility with new measurement tools. Also, the scoring system can now be applied to anyone ages 2 and older.

The Life’s Essential 8™ components of optimal cardiovascular health are divided into two major areas – health behaviors and health factors. Health behaviors include diet, physical activity, nicotine exposure and sleep. Health factors are body mass index, cholesterol levels, blood sugar and blood pressure. “The idea of optimal cardiovascular health is important because it gives people positive goals to work toward at any stage of life,” said Lloyd-Jones.

“Life’s Simple 7™ has served as a proven, powerful tool for understanding how to achieve healthy aging and ways to improve cardiovascular health while decreasing the risks of developing heart disease and stroke, as well as cancer, dementia and many other chronic diseases,” he said. “Given the evolving research, it was important to address some limitations to the original metrics, particularly in ways they’ve been applied to people from diverse racial and ethnic populations.”

Lloyd-Jones explained that some of the previous metrics, such as diet, were not as sensitive to differences among people, or as responsive to changes over time within a single individual. “We felt it was the right time to conduct a comprehensive review of the latest research to refine the existing metrics and consider any new metrics that add value to assessing cardiovascular health for all people.”

Life’s Essential 8™ includes:

1. Diet (updated): A new guide to assess diet quality for adults and children at the individual level (for individual health care and dietary counseling) and at the population level (for research and public health purposes).

  • At the population level, dietary assessment is based on daily intake of elements in the Dietary Approaches to Stop Hypertension (DASH) eating pattern. The DASH-style diet score has eight components: high intake of fruits, vegetables, nuts and legumes, whole grains, low-fat dairy, and low intake of sodium, red and processed meats, and sweetened drinks.
  • For individuals, the Mediterranean Eating Pattern for Americans (MEPA) is used to assess and monitor cardiovascular health. The MEPA is a DASH-style eating pattern that can be measured with 16 yes or no questions about the weekly frequency of eating olive oil, vegetables, berries, meat, fish, dairy, grains, etc. The MEPA screener does not include consumption of sugar-sweetened beverages, so clinicians are encouraged to ask at the time of assessment.

2. Physical activity (no changes): Activity is measured by the total number of minutes of moderate or vigorous physical activity per week, as defined by the U.S. Physical Activity Guidelines for Americans, 2nd edition. The optimal level is 150 minutes of moderate physical activity or more per week or 75 minutes per week of vigorous-intensity physical activity for adults; 420 minutes or more per week for children ages 6 and older; and age-specific modifications for younger children.

3. Nicotine exposure (updated): Use of inhaled nicotine-delivery systems, which includes e-cigarettes or vaping devices, is added since the previous metric only monitored traditional, combustible cigarettes. This reflects use by adults and youth and their implications on long-term health. Life’s Essential 8™ also includes second-hand smoke exposure for children and adults.

4. Sleep duration (new): Sleep duration is associated with cardiovascular health. Measured by average hours of sleep per night, the ideal level is 7-9 hours daily for adults. Ideal daily sleep ranges for children are 10-16 hours per 24 hours for ages 5 and younger; 9-12 hours for ages 6-12 years; and 8-10 hours for ages 13-18 years.

5. Body mass index (no changes): The writing group acknowledges that body mass index (BMI) is an imperfect metric, yet it is easily calculated and widely available; therefore, BMI continues as a reasonable gauge to assess weight categories that may lead to health problems. BMI of 18.5–24.9 is associated with the highest levels of cardiovascular health. The writing group notes that BMI ranges and the subsequent health risks associated with them may differ among people from diverse racial or ethnic backgrounds or ancestry. This aligns with the World Health Organization’s recommendations to adjust BMI ranges for people of Asian or Pacific Islander ancestry because recent evidence indicates their risk of conditions such as CVD or Type 2 diabetes is higher at a lower BMI.

6. Blood lipids (updated): The metric for blood lipids (cholesterol and triglycerides) is updated to use non-HDL cholesterol as the preferred number to monitor, rather than total cholesterol. HDL is the “good” cholesterol. Other forms of cholesterol, when high, are linked to CVD risk. This shift is made because non-HDL cholesterol can be measured without fasting beforehand (thereby increasing its availability at any time of day and implementation at more appointments) and reliably calculated among all people.

7. Blood glucose (updated): This metric is expanded to include the option of hemoglobin A1c readings or blood glucose levels for people with or without Type 1 or Type 2 diabetes or prediabetes. Hemoglobin A1c can better reflect long-term glycemic control.

8. Blood pressure (no changes): Blood pressure criteria remain unchanged from the Association’s 2017 guidelines that established levels less than 120/80 mm Hg as optimal, and hypertension defined as 130-139 mm Hg systolic pressure (the top number in a reading) or 80-89 mm Hg diastolic pressure (bottom number).

Each component of Life’s Essential 8™, which is assessed by the My Life Check tool, has an updated scoring system ranging from 0 to 100 points. The overall cardiovascular health score from 0 to 100 points is the average of the scores for each of the 8 health measures. Overall scores below 50 indicate “poor” cardiovascular health, and 50-79 is considered “moderate” cardiovascular health. Scores of 80 and above indicate “high” cardiovascular health. The advisory recommends measuring cholesterol, blood sugar, blood pressure, height and weight at least every five years for the most complete and accurate Life’s Essential 8™ score.

The writing group also reviewed data about the impacts of stress, mental health and social determinants of health, such as access to health care, income or education level, and structural racism, which are critical to understanding the foundations of health, particularly among people from diverse racial and ethnic populations.

“We considered social determinants of health carefully in our update and determined more research is needed on these components to establish their measurement and inclusion in the future,” said Lloyd-Jones. “Nonetheless, social and structural determinants, as well as psychological health and well-being, are critical, foundational factors in an individual’s or a community’s opportunity to preserve and improve cardiovascular health. We must consider and address all of these issues for people to have the opportunity for a full, healthy life as measured by Life’s Essential 8™.”

“Life’s Essential 8™ is a major step forward in our ability to identify when cardiovascular health can be preserved and when it is sub-optimal. It should energize efforts to improve cardiovascular health for all people and at every life stage,” Lloyd-Jones concluded.

Source: American Heart Association