Middle age may be much more stressful now than in the '90s

May 7, 2020

Science Daily/Penn State

If life feels more stressful now than it did a few decades ago, you're not alone. Even before the novel coronavirus started sweeping the globe, a new study found that life may be more stressful now than it was in the 1990s.

A team of researchers led by Penn State found that across all ages, there was a slight increase in daily stress in the 2010s compared to the 1990s. But when researchers restricted the sample to people between the ages of 45 and 64, there was a sharp increase in daily stress.

"On average, people reported about 2 percent more stressors in the 2010s compared to people in the past," said David M. Almeida, professor of human development and family studies at Penn State. "That's around an additional week of stress a year. But what really surprised us is that people at mid-life reported a lot more stressors, about 19 percent more stress in 2010 than in 1990. And that translates to 64 more days of stress a year."

Almeida said the findings were part of a larger project aiming to discover whether health during the middle of Americans' lives has been changing over time.

"Certainly, when you talk to people, they seem to think that daily life is more hectic and less certain these days," Almeida said. "And so we wanted to actually collect that data and run the analyses to test some of those ideas."

For the study, the researchers used data collected from 1,499 adults in 1995 and 782 different adults in 2012. Almeida said the goal was to study two cohorts of people who were the same age at the time the data was collected but born in different decades. All study participants were interviewed daily for eight consecutive days.

During each daily interview, the researchers asked the participants about their stressful experiences throughout the previous 24 hours. For example, arguments with family or friends or feeling overwhelmed at home or work. The participants were also asked how severe their stress was and whether those stressors were likely to impact other areas of their lives.

"We were able to estimate not only how frequently people experienced stress, but also what those stressors mean to them," Almeida said. "For example, did this stress affect their finances or their plans for the future. And by having these two cohorts of people, we were able to compare daily stress processes in 1990 with daily stress processes in 2010."

After analyzing the data, the researchers found that participants reported significantly more daily stress and lower well-being in the 2010s compared to the 1990s. Additionally, participants reported a 27 percent increase in the belief that stress would affect their finances and a 17 percent increase in the belief that stress would affect their future plans.

Almeida said he was surprised not that people were more stressed now than in the 90s, but at the age group that was mainly affected.

"We thought that with the economic uncertainty, life might be more stressful for younger adults," Almeida said. "But we didn't see that. We saw more stress for people at mid-life. And maybe that's because they have children who are facing an uncertain job market while also responsible for their own parents. So it's this generational squeeze that's making stress more prevalent for people at mid-life."

Almeida said that while there used to be a stereotype about people experiencing a midlife crisis because of a fear of death and getting older, he suspects the study findings -- recently published in the journal American Psychologist -- suggest midlife distress may be due to different reasons.

"It may have to do with people at mid-life being responsible for a lot of people," Almeida said. "They're responsible for their children, oftentimes they're responsible for their parents, and they may also be responsible for employees at work. And with that responsibility comes more daily stress, and maybe that's happening more so now than in the past."

Additionally, Almeida said the added stress could partially be due to life "speeding up" due to technological advances. This could be particularly true during stressful times like the coronavirus pandemic, when tuning out the news can seem impossible.

"With people always on their smartphones, they have access to constant news and information that could be overwhelming," Almeida said.

Susan T. Charles, University of California, Irvine; Jacqueline Mogle, Penn State; Johanna Drewelies, Humboldt University Berlin; Carolyn M. Aldwin, Oregon State University; Avron Spiro III, Boston University Schools of Public Health and Medicine and Department of Veteran's Affairs; and Denis Gerstorf, Humboldt University Berlin and Penn State, also participated in this work.

https://www.sciencedaily.com/releases/2020/05/200507094745.htm

Regularly attending religious services associated with lower risk of deaths of despair

May 6, 2020

Science Daily/Harvard T.H. Chan School of Public Health

People who attended religious services at least once a week were significantly less likely to die from "deaths of despair," including deaths related to suicide, drug overdose, and alcohol poisoning, according to new research led by Harvard T.H. Chan School of Public Health. The study showed that the association between service attendance and lower risk of deaths from despair was somewhat stronger for women in the study than for men.

"Despair is something that can confront anyone dealing with severe difficulties or loss. While the term 'deaths of despair' was originally coined in the context of working class Americans struggling with unemployment, it is a phenomenon that is relevant more broadly, such as to the health care professionals in our study who may be struggling with excessive demands and burnout, or to anyone facing loss. As such, we need to look for important community resources that can protect against it," said Tyler VanderWeele, John L. Loeb and Frances Lehman Loeb Professor of Epidemiology at Harvard Chan School. VanderWeele is also director of the Human Flourishing Program and co-director of the Initiative on Health, Religion and Spirituality at Harvard University.

The study will be published online in JAMA Psychiatry on May 6, 2020.

Religion may be a social determinant of health, and previous research has shown that attending religious services may be associated with a lower risk of various factors related to despair, including heavy drinking, substance misuse, and suicidality.

For this study, researchers analyzed data from the Nurses' Health Study II on 66,492 women as well as data from the Health Professionals Follow-Up Study on 43,141 men. Among the women, there were 75 deaths from despair: 43 suicides, 20 deaths from poisoning, and 12 deaths from liver disease and cirrhosis. Among the men there were 306 deaths from despair: 197 suicides, 6 deaths from poisoning, and 103 deaths from liver diseases and cirrhosis.

After adjusting for numerous variables, the study showed that women who attended services at least once per week had a 68% lower risk of death from despair compared to those never attending services. Men who attended services at least once per week had 33% lower risk of death from despair.

The study authors noted that religious participation may serve as an important antidote to despair and an asset for sustaining a sense of hope and meaning. They also wrote that religion may be associated with strengthened psychosocial resilience by fostering a sense of peace and positive outlook, and promoting social connectedness.

"These results are perhaps especially striking amidst the present COVID-19 pandemic," said Ying Chen, research associate and data scientist at the Human Flourishing Program at Harvard's Institute for Quantitative Social Science, and first author of the paper. "They are striking in part because clinicians are facing such extreme work demands and difficult conditions, and in part because many religious services have been suspended. We need to think what might be done to extend help to those at risk for despair."

https://www.sciencedaily.com/releases/2020/05/200506133627.htm

Eyes send an unexpected signal to the brain

A subset of retinal neurons communicates differently from the rest of the eye

April 30, 2020

Science Daily/Northwestern University

For decades, biology textbooks have stated that eyes communicate with the brain exclusively through one type of signaling pathway. But a new discovery shows that some retinal neurons take a road less traveled.

New research, led by Northwestern University, has found that a subset of retinal neurons sends inhibitory signals to the brain. Before, researchers believed the eye only sends excitatory signals. (Simply put: Excitatory signaling makes neurons to fire more; inhibitory signaling makes neurons to fire less.)

The Northwestern researchers also found that this subset of retinal neurons is involved in subconscious behaviors, such as synchronization of circadian rhythms to light/dark cycles and pupil constriction to intense bright lights. By better understanding how these neurons function, researchers can explore new pathways by which light influences our behavior.

"These inhibitory signals prevent our circadian clock from resetting to dim light and prevent pupil constriction in low light, both of which are adaptive for proper vision and daily function," said Northwestern's Tiffany Schmidt, who led the research. "We think that our results provide a mechanism for understanding why our eye is so exquisitely sensitive to light, but our subconscious behaviors are comparatively insensitive to light."

The research will be published in the May 1 issue of the journal Science.

Schmidt is an assistant professor of neurobiology at Northwestern's Weinberg College of Arts and Sciences. Takuma Sonoda, a former Ph.D. student in the Northwestern University Interdepartmental Neuroscience program, is the paper's first author.

To conduct the study, Schmidt and her team blocked the retinal neurons responsible for inhibitory signaling in a mouse model. When this signal was blocked, dim light was more effective at shifting the mice's circadian rhythms.

"This suggests that there is a signal from the eye that actively inhibits circadian rhythms realignment when environmental light changes, which was unexpected," Schmidt said. "This makes some sense, however, because you do not want to adjust your body's entire clock for minor perturbations in the environmental light/dark cycle, you only want this massive adjustment to take place if the change in lighting is robust."

Schmidt's team also found that, when the inhibitory signals from the eye were blocked, mice's pupils were much more sensitive to light.

"Our working hypothesis is that this mechanism keeps pupils from constricting in very low light," Sonoda said. "This increases the amount of light hitting your retina, and makes it easier to see in low light conditions. This mechanism explains, in least part, why your pupils avoid constricting until bright light intensifies."

https://www.sciencedaily.com/releases/2020/04/200430150201.htm

Heart disease more likely for adults with dysfunctional childhoods

Trauma, neglect, family dysfunction in childhood leads to health issues in 50s, 60s

April 28, 2020

Science Daily/Northwestern University

Children who experience trauma, abuse, neglect and family dysfunction are at increased risk of having heart disease in their 50s and 60s, according to a new Northwestern Medicine study.

Results from the study showed people exposed to the highest levels of childhood family environment adversity were more than 50 percent more likely to have a cardiovascular disease event such as a heart attack or stroke over a 30-year follow-up.

The longitudinal study of more than 3,600 participants is among the first to describe the trajectory of cardiovascular disease and death based on family environment ratings from young adulthood into older middle age.

The findings were published today, April 28, in the Journal of the American Heart Association.

Children who experience this type of adversity are predisposed to higher rates of lifelong stress, smoking, anxiety, depression and sedentary lifestyle that persist into adulthood. These can lead to increased body mass index (BMI), diabetes, increased blood pressure, vascular dysfunction and inflammation.

"This population of adults is much more likely to partake in risky behaviors -- for example, using food as a coping mechanism, which can lead to problems with weight and obesity," said first author Jacob Pierce, a fourth-year medical student at Northwestern University Feinberg School of Medicine. "They also have higher rates of smoking, which has a direct link to cardiovascular disease."

Adults who were exposed to these risk factors as children may benefit from counseling on the link between coping with stress and controlling smoking and obesity, but more research is needed, Pierce said.

"Early childhood experiences have a lasting effect on adult mental and physical well-being, and a large number of American kids continue to suffer abuse and dysfunction that will leave a toll of health and social functioning issues throughout their lives," said senior author Joseph Feinglass, research professor of medicine and of preventive medicine at Feinberg. "Social and economic support for young children in the United States, which is low by the standards of other developed countries, has the biggest 'bang for the buck' of any social program."

The study used the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a prospective cohort that has followed participants from recruitment in 1985-1986 through 2018, to determine how childhood psychosocial environment relates to cardiovascular disease incidence and mortality in middle age.

To get a broad idea of what a study participant's family environment was like during their childhood, participants answered survey questions that asked questions such as, "How often did a parent or other adult in the household make you feel that you were loved, supported, and cared for?" or "How often did a parent or other adult in the household swear at you, insult you, put you down or act in a way that made you feel threatened?"

The most predictive of cardiovascular disease later in life was "Did your family know what you were up to as a kid?" Pierce said.

While the study didn't specifically address attentiveness of parents, the findings indicate parents' involvement in their children's lives could impact their health later in life.

https://www.sciencedaily.com/releases/2020/04/200428165751.htm

How the heart affects our perception

April 28, 2020

Science Daily/Max Planck Institute for Human Cognitive and Brain Sciences

When we encounter a dangerous situation, signals from the brain make sure that the heart beats faster. When we relax the heart slows down. But the heartbeat also affects the brain but the underlying mechanisms are unclear. Researchers have now identified two mechanisms underpinning how the heart influences our perception, the brain, and how these mechanisms differ between individuals.

The first mechanism establishes a relationship between the phase of the heartbeat and conscious experience. In a regular rhythm, the heart contracts in the so-called systolic phase and pumps blood into the body. In a second phase, the diastolic phase, the blood flows back and the heart fills up again. In a previous publication from the MPI CBS, it was reported that perception of external stimuli changes with the heartbeat. In systole, we are less likely to detect a weak electric stimulus in the finger compared to diastole.

Now, in a new study, Esra Al and colleagues have found the reason for this change in perception: Brain activity is changing over the heart cycle. In systole a specific component of brain activity, which is associated with consciousness, the so called P300-component is suppressed. In other words, it seems that -- in systole -- the brain makes sure that certain information is kept out of conscious experience. The brain seems to take into account the pulse which floods the body in systole and predicts that pulse-associated bodily changes are "not real" but rather due to the pulse. Normally, this helps us to not be constantly disturbed by our pulse. However, when it comes to weak stimuli which coincide with systole we might miss them, although they are real.

During their investigations on heart-brain interactions, Al and colleagues also revealed a second effect of heartbeat on perception: If a person's brain shows a higher response to the heartbeat, the processing of the stimulus in the brain is attenuated -- the person detects the stimulus less. "This seems to be a result of directing our attention between external environmental signals and internal bodily signals.," explains study author Al. In other words, a large heartbeat-evoked potential seems to reflect a "state of mind," in which we are more focused on the functioning of our inner organs such as the blood circulation, however less aware of stimuli from the outside world.

The results not only have implications for our understanding of heart-brain interactions in healthy persons, but also in patients. The senior author, Arno Villringer explains, "The new results might help to explain why patients after stroke often suffer from cardiac problems and why patients with cardiac disease often have impaired cognitive function."

The researchers investigated these relationships by sending weak electrical stimuli to electrodes clamped onto the study participants fingers. In parallel, they recorded each participants' brain processes using an EEG and their cardiac activity using an EKG.

https://www.sciencedaily.com/releases/2020/04/200428131707.htm

Stress thwarts our ability to plan ahead by disrupting how we use memory

April 3, 2020

Science Daily/Stanford University

New research from Stanford University has found that stress can hinder our ability to develop informed plans by preventing us from being able to make decisions based on memory.

"We draw on memory not just to project ourselves backward into the past but to project ourselves forward, to plan," said Stanford psychologist Anthony Wagner, who is the senior author of the paper detailing this work, published April 2 in Current Biology. "Stress can rob you of the ability to draw on cognitive systems underlying memory and goal-directed behavior that enable you to solve problems more quickly, more efficiently and more effectively."

Combined with previous work from Wagner's Memory Lab and others, these findings could have broad implications for understanding how different people plan for the future -- and how lack of stress may afford some people a greater neurologically-based opportunity to think ahead.

"It's a form of neurocognitive privilege that people who are not stressed can draw on their memory systems to behave more optimally," said Wagner, who is the Lucie Stern Professor in the Social Sciences at Stanford's School of Humanities and Sciences. "And we may fail to actually appreciate that some individuals might not be behaving as effectively or efficiently because they are dealing with something, like a health or economic stressor, that reduces that privilege."

Take a virtual walk

The researchers conducted experiments where they monitored participants' behavior and brain activity -- via fMRI -- as they navigated through virtual towns. After participants became very familiar winding routes in a dozen towns, they were dropped onto one of the memorized paths and told to navigate to a goal location.

To test the effects of stress, the researchers warned some participants that they could receive a mild electric shock, unrelated to their performance, during their virtual rambles. Participants who didn't have to worry about being randomly shocked tended to envision and take novel shortcuts based on memories acquired from prior journeys, whereas the stressed participants tended to fall back on the meandering, habitual routes.

Prior to beginning their trek, the participants were virtually held in place at their starting position. Brain scans from this period showed that the stressed individuals were less likely than their counterparts to activate the hippocampus -- a brain structure that would have been active if they were mentally reviewing previous journeys. They also had less activity in their frontal-parietal lobe networks, which allows us to bring neural processes in line with our current goals. Previous work by the researchers had found that stress hinders this neural machinery, making it harder for us to retrieve and use memories.

The researchers believe their new study is the first to show how hippocampal-frontal lobe network disruption takes memory replay offline during a planning session due to stress.

"Its kind of like our brain is pushed into a more low-level thought-process state, and that corresponds with this reduced planning behavior," said Thackery Brown, who was a postdoctoral scholar in the Memory Lab during this research and is lead author of the paper.

Stress and old age

Looking forward, the researchers are especially interested in how the relationship between stress and memory affects older populations, who often experience both health and economic issues. Older people are also more likely to be concerned about memory loss. Together, these combined stressors could contribute to a diminished ability to remember, which could further exacerbate their stress and also impair their ability to deal with it.

Brown has begun conducting studies similar to the virtual navigation experiments with participants between the ages of 65 and 80 to try to better understand how the associations between stress, memory and planning play out in older populations.

"It's a powerful thing to think about how stressful events might affect planning in your grandparents," said Brown, who is now an assistant professor at Georgia Institute of Technology. "It affects us in our youth and as we interact with and care for older members of our family, and then it becomes relevant to us in a different way when we are, ourselves, older adults."

https://www.sciencedaily.com/releases/2020/04/200403115103.htm

Gut communicates with the entire brain through cross-talking neurons

April 2, 2020

Science Daily/University of Illinois College of Agricultural, Consumer and Environmental Sciences

You know that feeling in your gut? We think of it as an innate intuition that sparks deep in the belly and helps guide our actions, if we let it. It's also a metaphor for what scientists call the "gut-brain axis," a biological reality in which the gut and its microbial inhabitants send signals to the brain, and vice versa.

It's not a surprise that the brain responds to signals in the gut, initiating motor functions involved with digestion. Directed by the brainstem, these types of basic biological actions are largely automatic. But what if the higher brain -- the thinking, emotional centers -- were influenced by signals in the gut, too? New University of Illinois research in rats shows the entire brain responds to the gut, specifically the small intestine, through neuronal connections.

To map the connections, researchers inserted neuron-loving viruses in the rats' small intestines and traced the viruses as they moved from neuron to neuron along the Vagus and spinal nerves and throughout the brain. The idea was virus movement mimicked the movement of normal signals through neurons from the gut to the brain and back.

"We saw a lot of connections in the brainstem and hindbrain regions. We knew these regions are involved in sensing and controlling the organs of the body, so there weren't any big surprises there. But things got more interesting as the viruses moved farther up into parts of the brain that are usually considered emotional centers or learning centers, cognitive places. They have all these multifaceted functions. So thinking about how information from the small intestine might be nudging those processes a little bit is really cool," says Coltan Parker, doctoral student in the Neuroscience Program at Illinois and lead author on a study published in Autonomic Neuroscience: Basic and Clinical.

The study represents the first complete map of neuronal connections between the small intestine -- what Parker and his co-authors call an "underloved" part of the digestive system -- and the entire brain. The involvement of cognitive and emotional centers hints at how the thinking brain sometimes overrides our feeling of being full, provides fodder to explore relationships between depression and digestive troubles, and more.

"Now we're actually finding the neuro-anatomy that might be involved in that 'feeling in your gut,'" says Megan Dailey, study co-author and program administrator in the College of Agricultural, Consumer and Environmental Sciences at Illinois.

In addition to showing just how extensive the connections are between the small intestine and the brain, the study uncovered a rarely documented feature of the neurons themselves.

Scientists have long assumed sensations from the gut, or anywhere in the body, traveled to the brain along one set of neurons (the sensory neurons), with instructions from the brain traveling back along a separate set of neurons (the motor neurons). But in their mapping study, Illinois researchers discovered some of the neurons -- about half -- were transmitting both sensory and motor signals.

They were capable of cross-talk within the same neuron.

"From the cortex to the brainstem, in pretty much every region we investigated, there was that 50% overlap of sensory-motor signals. It was throughout the brain, consistently," says study co-author Elizabeth Davis. Davis is a 2018 graduate of the Illinois Neuroscience Program and is currently studying as a postdoctoral scholar at the University of Southern California.

The same pattern -- 50% of neurons having both sensory and motor signaling capabilities -- had only been shown one other time, in a study mapping neuronal connections between fat tissue and the brain. The researchers point out new evidence of the same crosstalk pattern could suggest a general architecture of neuronal networks between the body and brain.

"This study shows that sensorimotor feedback loops are abundant across all levels of the brain. Up until now, it has really been unknown how information in the small intestine, about nutrients or anything else, can get up to the brain and affect cognitive-emotional processes, and then how those processes can come back down and affect the gut," Parker says. "With more research, we may finally begin to understand how hunger makes us 'hangry,' or how a stressful day becomes an irritable bowel."

https://www.sciencedaily.com/releases/2020/04/200402155733.htm

To stay positive, live in the moment -- but plan ahead

March 25, 2020

Science Daily/North Carolina State University

A recent study from North Carolina State University finds that people who manage to balance living in the moment with planning for the future are best able to weather daily stress without succumbing to negative moods.

"It's well established that daily stressors can make us more likely to have negative affect, or bad moods," says Shevaun Neupert, a professor of psychology at NC State and corresponding author of a paper on the recent work. "Our work here sheds additional light on which variables influence how we respond to daily stress."

Specifically, the researchers looked at two factors that are thought to influence how we handle stress: mindfulness and proactive coping.

Mindfulness is when people are centered and living in the moment, rather than dwelling in the past or worrying about the future. Proactive coping is when people engage in planning to reduce the likelihood of future stress.

To see how these factors influence responses to stress, the researchers looked at data from 223 study participants. The study included 116 people between the ages of 60 and 90, and 107 people between the ages of 18 and 36. All of the study participants were in the United States.

All of the study participants were asked to complete an initial survey in order to establish their tendency to engage in proactive coping. Participants were then asked to complete questionnaires for eight consecutive days that explored fluctuations in mindfulness. On those eight days, participants were also asked to report daily stressors and the extent to which they experienced negative mood.

The researchers found that engaging in proactive coping was beneficial at limiting the effect of daily stressors, but that this advantage essentially disappeared on days when a participant reported low mindfulness.

"Our results show that a combination of proactive coping and high mindfulness result in study participants of all ages being more resilient against daily stressors," Neupert says. "Basically, we found that proactive planning and mindfulness account for about a quarter of the variance in how stressors influenced negative affect.

"Interventions targeting daily fluctuations in mindfulness may be especially helpful for those who are high in proactive coping and may be more inclined to think ahead to the future at the expense of remaining in the present."

https://www.sciencedaily.com/releases/2020/03/200325130650.htm

Analysis predicts purified fish oil could prevent thousands of cardiovascular events

March 25, 2020

Science Daily/University of California - Irvine

Researchers from the University of California, Irvine have conducted a statistical analysis that predicts more than 70,000 heart attacks, strokes and other adverse cardiovascular events could be prevented each year in the U.S. through the use of a highly purified fish oil therapy.

Led by Nathan D. Wong, PhD, professor and director of the Heart Disease Prevention Program in the Division of Cardiology at the UCI School of Medicine, the abstract of the statistical analysis was accepted by the American College of Cardiology and is slated to be presented at the upcoming ACC.20/World Congress of Cardiology virtual conference taking place March 28-30. The analysis utilizes data from the Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey (NHANES), and inclusion criteria from a multinational clinical trial led by investigators from Harvard University called REDUCE-IT, which was published in the New England Journal of Medicine in January of 2019.

The REDUCE-IT trial showed patients with known cardiovascular disease or diabetes and multiple risk factors who have elevated triglyceride levels and are at increased risk for ischemic events benefitted substantially from icosapent ethyl, a highly purified fish oil therapy, which lowered cardiovascular events, including heart attacks and strokes, by 25 percent. Positive results were not found in other trials, possibly due to mixtures with other omega-3 fatty acids such as DHA, or inadequate dosages according to Wong.

"Our analysis extends the findings of the REDUCE-IT trial by estimating its potential impact on the U.S. population," said Wong. "By using inclusion criteria and cardiovascular disease event rates from the REDUCE-IT trial and applying it to data on US adults from NHANES, we were able to estimate the beneficial impact icosapent ethyl could have on preventing initial and total cardiovascular events in eligible U.S. adults with cardiovascular disease or diabetes and multiple risk factors."

Wong's analysis is the first to project the findings of REDUCE-IT to the overall U.S. population.

"When you consider that for every 21 patients treated with icosapent ethyl you can spare a cardiovascular event, you begin to see the implications of our results," said Wong.

Icosapent ethyl is a purified stable eicosapentaenoic acid (EPA) which was recently approved by the Federal Drug Administration (FDA) in conjunction with maximally tolerated statin therapy to reduce the risk of cardiovascular events in certain adults with elevated triglyceride levels. The only drug of its kind to show such an effect, icosapent ethyl, is currently marketed under the name Vascepa® by Amarin Pharma. The EPA therapy has also gained the support of several major societies, which have incorporated it in various guidelines, scientific statements and advisories, including the American Diabetes Association, American Heart Association, National Lipid Association, and the European Society of Cardiology/European Atherosclerosis Society.

https://www.sciencedaily.com/releases/2020/03/200325131536.htm

Higher daily step count linked with lower all-cause mortality

Science Daily NIH/National Cancer Institute

In a new study, higher daily step counts were associated with lower mortality risk from all causes. The research team, which included investigators from the National Cancer Institute (NCI) and the National Institute on Aging (NIA), both parts of the National Institutes of Health, as well as from the Centers for Disease Control and Prevention (CDC), also found that the number of steps a person takes each day, but not the intensity of stepping, had a strong association with mortality.

The findings were published March 24, 2020, in the Journal of the American Medical Association.

"While we knew physical activity is good for you, we didn't know how many steps per day you need to take to lower your mortality risk or whether stepping at a higher intensity makes a difference," said Pedro Saint-Maurice, Ph.D., of NCI's Division of Cancer Epidemiology and Genetics, first author of the study. "We wanted to investigate this question to provide new insights that could help people better understand the health implications of the step counts they get from fitness trackers and phone apps."

Previous studies have been done on step counts and mortality. However, they were conducted primarily with older adults or among people with debilitating chronic conditions. This study tracked a representative sample of U.S. adults aged 40 and over; approximately 4,800 participants wore accelerometers for up to seven days between 2003 and 2006. The participants were then followed for mortality through 2015 via the National Death Index. The researchers calculated associations between mortality and step number and intensity after adjustment for demographic and behavioral risk factors, body mass index, and health status at the start of the study.

They found that, compared with taking 4,000 steps per day, a number considered to be low for adults, taking 8,000 steps per day was associated with a 51% lower risk for all-cause mortality (or death from all causes). Taking 12,000 steps per day was associated with a 65% lower risk compared with taking 4,000 steps. In contrast, the authors saw no association between step intensity and risk of death after accounting for the total number of steps taken per day.

"At NIA, we've long studied how exercise is important for older adults, and it's good to see further evidence from a large study with a broad sample that the main thing is to get moving for better overall health as we age," said Eric Shiroma, Ph.D., a co-author and NIA Intramural Research Program scientist.

In analyses by subgroups of participants, the authors found that higher step counts were associated with lower all-cause death rates among both men and women; among both younger and older adults; and among white, black, and Mexican-American adults. In secondary outcomes of the study, higher step counts were also associated with lower rates of death from cardiovascular disease and cancer.

Data collection was conducted through the CDC's National Health and Nutrition Examination Survey (NHANES), a program of studies designed to assess a nationally representative sample of the health and nutritional status of adults and children in the United States.

The researchers were surprised they didn't find an association between higher stepping intensity and all-cause mortality after adjusting for the total number of steps per day. Because few studies have investigated an association between mortality and intensity among adults going about their daily lives, the study authors wrote that future studies of walking intensity and mortality are warranted.

Although the study authors controlled for factors that could have affected the results, the study is observational and cannot prove causality. Nevertheless, their findings are consistent with current recommendations that adults should move more and sit less throughout the day. Adults who do any amount of physical activity gain some health benefits. For even greater health benefits, adults are recommended to get at least 150 minutes of moderate-intensity physical activity per week.

"Being physically active has many benefits, including reducing a person's risk of obesity, heart disease, type 2 diabetes, and some cancers. And on a daily basis, it can help people feel better and sleep better," said Janet Fulton, Ph.D., of CDC's Division of Nutrition, Physical Activity, and Obesity. "CDC is working with communities and partners across the country, as part of the Active People, Healthy Nation initiative, to make it easier, safer, and more convenient for people to be active in their own communities."

https://www.sciencedaily.com/releases/2020/03/200324202033.htm