Physical activity reduces stress-related brain activity to lower cardiovascular disease risk

New research indicates that physical activity lowers cardiovascular disease risk in part by reducing stress-related signaling in the brain.

In the study, which was led by investigators at Massachusetts General Hospital (MGH), a founding member of the Mass General Brigham healthcare system and published in the Journal of the American College of Cardiology, people with stress-related conditions such as depression experienced the most cardiovascular benefits from physical activity.

To assess the mechanisms underlying the psychological and cardiovascular disease benefits of physical activity, Ahmed Tawakol, MD, an investigator and cardiologist in the Cardiovascular Imaging Research Center at Massachusetts General Hospital, and his colleagues analyzed medical records and other information of 50,359 participants from the Mass General Brigham Biobank who completed a physical activity survey.

A subset of 774 participants also underwent brain imaging tests and measurements of stress-related brain activity.

Over a median follow-up of 10 years, 12.9% of participants developed cardiovascular disease. Participants who met physical activity recommendations had a 23% lower risk of developing cardiovascular disease compared with those not meeting these recommendations.

Individuals with higher levels of physical activity also tended to have lower stress-related brain activity. Notably, reductions in stress-associated brain activity were driven by gains in function in the prefrontal cortex, a part of the brain involved in executive function (i.e., decision making, impulse control) and is known to restrain stress centers of the brain. Analyses accounted for other lifestyle variables and risk factors for coronary disease.

Moreover, reductions in stress-related brain signaling partially accounted for physical activity's cardiovascular benefit.

As an extension of this finding, the researchers found in a cohort of 50,359 participants that the cardiovascular benefit of exercise was substantially greater among participants who would be expected to have higher stress-related brain activity, such as those with pre-existing depression.

"Physical activity was roughly twice as effective in lowering cardiovascular disease risk among those with depression. Effects on the brain's stress-related activity may explain this novel observation," says Tawakol, who is the senior author of the study.

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Does the time of day you move your body make a difference to your health?

Undertaking the majority of daily physical activity in the evening is linked to the greatest health benefits for people living with obesity, according to researchers from the University of Sydney, Australia who followed the trajectory of 30,000 people over almost 8 years.

Using wearable device data to categorise participant's physical activity by morning, afternoon or evening, the researchers uncovered that those who did the majority of their aerobic moderate to vigorous physical activity- the kind that raises our heartrate and gets us out of breath- between 6pm and midnight had the lowest risk of premature death and death from cardiovascular disease.

The frequency with which people undertook moderate to vigorous physical activity (MVPA) in the evening, measured in short bouts up to or exceeding three minutes, also appeared to be more important than their total amount of physical activity daily.

The study, led by researchers from the University's Charles Perkins Centre is published in the journal Diabetes Care today.

"Due to a number of complex societal factors, around two in three Australians have excess weight or obesity which puts them at a much greater risk of major cardiovascular conditions such as heart attacks and stroke, and premature death," said Dr Angelo Sabag, Lecturer in Exercise Physiology at the University of Sydney.

"Exercise is by no means the only solution to the obesity crisis, but this research does suggest that people who can plan their activity into certain times of the day may best offset some of these health risks."

Smaller clinical trials have shown similar results, however the large scale of participant data in this study, the use of objective measures of physical activity and hard outcomes, such as premature death, makes these findings significant.

Joint first author Dr Matthew Ahmadi also stressed that the study did not just track structured exercise. Rather researchers focused on tracking continuous aerobic MVPA in bouts of 3 minutes or more as previous research shows a strong association between this type of activity, glucose control and lowered cardiovascular disease risk compared with shorter (non-aerobic) bouts.

"We didn't discriminate on the kind of activity we tracked, it could be anything from power walking to climbing the stairs, but could also include structured exercise such as running, occupational labour or even vigorously cleaning the house," said Dr Ahmadi, National Heart Foundation postdoctoral research fellow at the Charles Perkins Centre, University of Sydney.

While observational, the findings of the study support the authors original hypothesis, which is the idea -- based on previous research -- that people living with diabetes or obesity, who are already glucose intolerant in the late evening, may be able to offset some of that intolerance and associated complications, by doing physical activity in the evening.

The researchers used data from UK Biobank and included 29,836 adults aged over 40 years of age living with obesity, of whom 2,995 participants were also diagnosed with Type 2 diabetes.

Participants were categorised into morning, afternoon of evening MVPA based on when they undertook the majority of their aerobic MVPA as measured by a wrist accelerometer worn continuously for 24 hours a day over 7 days at study onset.

The team then linked health data (from the National Health Services and National Records of Scotland) to follow participants health trajectory for 7.9 years. Over this period they recorded 1,425 deaths, 3,980 cardiovascular events and 2,162 microvascular disfunction events.

To limit bias, the researchers accounted for differences such as age, sex, smoking, alcohol intake, fruit and vegetable consumption, sedentary time, total MVPA, education, medication use and sleep duration. They also excluded participants with pre-existing cardiovascular disease and cancer.

The researchers say the length of the study follow-up and additional sensitivity analysis bolster the strength of their findings however, due to the observational design, they cannot completely rule out potential reverse causation. This is the possibility that some participants had lower aerobic MVPA levels due to underlying or undiagnosed disease.

Professor Emmanuel Stamatakis, Director of the Mackenzie Wearables Research Hub at the Charles Perkins Centre and senior author on the paper, said the sophistication of studies in the wearables field is providing huge insights into the patterns of activity that are most beneficial for health.

"It is a really exciting time for researchers in this field and practitioners alike, as wearable device-captured data allow us to examine physical activity patterns at a very high resolution and accurately translate findings into advice that could play an important role in health care," said Professor Stamatakis.

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Daily step count of 9,000 to 10,000 may counteract risk of death and cardiovascular disease in highly sedentary people

In good news for office workers, a new study from the University of Sydney's Charles Perkins Centre (Australia) has found increasing your step count may counteract the health consequences of too much sedentary time each day.

The study of over 72,000 people, published in the British Journal of Sports Medicine, found every additional step up to around 10,000 steps a day was linked to reduced risk of death (39 percent) and cardiovascular disease (21 percent) regardless of how much remaining time was spent sedentary.

Previous studies have shown an association between greater daily step count and lower levels of death and CVD, and separate studies have linked high levels of sedentary behaviour with increased risks of CVD and death. However, this is the first to objectively measure, via wrist-worn wearables, if daily steps could offset the health risks of high sedentary behaviour.

Lead author and research fellow, Dr Matthew Ahmadi said: "This is by no means a get out of jail card for people who are sedentary for excessive periods of time, however, it does hold an important public health message that all movement matters and that people can and should try to offset the health consequences of unavoidable sedentary time by upping their daily step count."

Senior author Professor Emmanuel Stamatakis, Director of the Mackenzie Wearables Research Hub at the Charles Perkins Centre, said this growing body of physical activity research using device-based measurement provided huge opportunities for public health.

"Step count is a tangible and easily understood measure of physical activity that can help people in the community, and indeed health professionals, accurately monitor physical activity. We hope this evidence will inform the first generation of device-based physical activity and sedentary behaviour guidelines, which should include key recommendations on daily stepping," said Professor Stamatakis.

How the study was conducted

Researchers used data on 72,174 individuals (average age 61; 58% female) from the UK Biobank study -- a major biomedical database -- who had worn an accelerometer device on their wrist for seven days to measure their physical activity. The accelerometer data were used to estimate daily step count and time spent sedentary, that is sitting or lying down while awake.

The research team then followed the health trajectory of the participants by linking hospitalisation data and death records.

The median daily step count for participants was 6222 steps/day, and 2200 steps/day (the lowest 5 percent of daily steps among all participants) was taken as the comparator for assessing the impact on death and CVD events of increasing step count.

The median time spent sedentary was 10.6 hours/day, so study participants sedentary for 10.5 hours/day or more were considered to have high sedentary time while those who spent less than 10.5 hours/day sedentary were classified as low sedentary time.

Adjustments were made to eliminate biases, such as excluding participants with poor health, who were underweight or had a health event within two years of follow-up. Researchers also took into account factors such as age, sex, ethnicity, education, smoking status, alcohol consumption, diet and parental history of CVD and cancer.

Findings

Over an average 6.9 years follow up, 1633 deaths and 6190 CVD events occurred.

After taking account of other potential influences, the authors calculated that the optimal number of steps per day to counteract high sedentary time was between 9000 to 10000 steps/day, which lowered mortality risk by 39 percent and incident CVD risk by 21 percent.

In both cases, 50 percent of the benefit was achieved at between 4000 and 4500 steps a day.

Study limitations

This is an observational study so can't establish direct cause and effect. And although the large sample size and long follow-up allowed the risk of bias to be reduced, the authors acknowledge the possibility that other unmeasured factors could affect results. As steps and sedentary time were obtained in a single time point, this could also lead to bias, they add.

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Any activity is better for your heart than sitting -- even sleeping

The study, supported by the British Heart Foundation (BHF) and published in the European Heart Journal, is the first to assess how different movement patterns throughout the 24-hour day are linked to heart health. It is the first evidence to emerge from the international Prospective Physical Activity, Sitting and Sleep (ProPASS) consortium.

Cardiovascular disease, which refers to all diseases of the heart and circulation, is the number one cause of mortality globally. In 2021, it was responsible for one in three deaths (20.5m), with coronary heart disease alone the single biggest killer. Since 1997, the number of people living with cardiovascular disease across the world has doubled and is projected to rise further.

In this study, researchers at UCL analysed data from six studies, encompassing 15,246 people from five countries, to see how movement behaviour across the day is associated with heart health, as measured by six common indicators*. Each participant used a wearable device on their thigh to measure their activity throughout the 24-hour day and had their heart health measured.

The researchers identified a hierarchy of behaviours that make up a typical 24-hour day, with time spent doing moderate-vigorous activity providing the most benefit to heart health, followed by light activity, standing and sleeping compared with the adverse impact of sedentary behaviour.

The team modelled what would happen if an individual changed various amounts of one behaviour for another each day for a week, in order to estimate the effect on heart health for each scenario. When replacing sedentary behaviour, as little as five minutes of moderate-vigorous activity had a noticeable effect on heart health.

For a 54-year-old woman with an average BMI of 26.5, for example, a 30-minute change translated into a 0.64 decrease in BMI, which is a difference of 2.4%. Replacing 30 minutes of daily sitting or lying time with moderate or vigorous exercise could also translate into a 2.5 cm (2.7%) decrease in waist circumference or a 1.33 mmol/mol (3.6%) decrease in glycated haemoglobin.

Dr Jo Blodgett, first author of the study from UCL Surgery & Interventional Science and the Institute of Sport, Exercise & Health, said: "The big takeaway from our research is that while small changes to how you move can have a positive effect on heart health, intensity of movement matters. The most beneficial change we observed was replacing sitting with moderate to vigorous activity -- which could be a run, a brisk walk, or stair climbing -- basically any activity that raises your heart rate and makes you breathe faster, even for a minute or two."

The researchers pointed out that although time spent doing vigorous activity was the quickest way to improve heart health, there are ways to benefit for people of all abilities -- it's just that the lower the intensity of the activity, the longer the time is required to start having a tangible benefit. Using a standing desk for a few hours a day instead of a sitting desk, for example, is a change over a relatively large amount of time but is also one that could be integrated into a working routine fairly easily as it does not require any time commitment.

Those who are least active were also found to gain the greatest benefit from changing from sedentary behaviours to more active ones.

Professor Emmanuel Stamatakis, joint senior author of the study from the Charles Perkins Centre and Faculty of Medicine and Health at the University of Sydney, said: "A key novelty of the ProPASS consortium is the use of wearable devices that better differentiate between types of physical activity and posture, allowing us to estimate the health effects of even subtle variations with greater precision."

Though the findings cannot infer causality between movement behaviours and cardiovascular outcomes, they contribute to a growing body of evidence linking moderate to vigorous physical activity over 24 hours with improved body fat metrics. Further long-term studies will be crucial to better understanding the associations between movement and cardiovascular outcomes.

Professor Mark Hamer, joint senior author of the study from UCL Surgery & Interventional Science and the Institute of Sport, Exercise & Health, said: "Though it may come as no surprise that becoming more active is beneficial for heart health, what's new in this study is considering a range of behaviours across the whole 24-hour day. This approach will allow us to ultimately provide personalised recommendations to get people more active in ways that are appropriate for them."

James Leiper, Associate Medical Director at the British Heart Foundation, said: "We already know that exercise can have real benefits for your cardiovascular health and this encouraging research shows that small adjustments to your daily routine could lower your chances of having a heart attack or stroke. This study shows that replacing even a few minutes of sitting with a few minutes of moderate activity can improve your BMI, cholesterol, waist size, and have many more physical benefits.

"Getting active isn't always easy, and it's important to make changes that you can stick to in the long-term and that you enjoy -- anything that gets your heart rate up can help. Incorporating 'activity snacks' such as walking while taking phone calls, or setting an alarm to get up and do some star jumps every hour is a great way to start building activity into your day, to get you in the habit of living a healthy, active lifestyle."

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The more you walk, the lower your risk of early death, even if you walk fewer than 5,000 steps

The number of steps you should walk every day to start seeing benefits to your health is lower than previously thought, according to the largest analysis to investigate this.

The study, published in the European Journal of Preventive Cardiology [1] today (Wednesday), found that walking at least 3967 steps a day started to reduce the risk of dying from any cause, and 2337 steps a day reduced the risk of dying from diseases of the heart and blood vessels (cardiovascular disease).

However, the new analysis of 226,889 people from 17 different studies around the world has shown that the more you walk, the greater the health benefits. The risk of dying from any cause or from cardiovascular disease decreases significantly with every 500 to 1000 extra steps you walk. An increase of 1000 steps a day was associated with a 15% reduction in the risk of dying from any cause, and an increase of 500 steps a day was associated with a 7% reduction in dying from cardiovascular disease.

The researchers, led by Maciej Banach, Professor of Cardiology at the Medical University of Lodz, Poland, and Adjunct Professor at the Ciccarone Center for the Prevention of Cardiovascular Disease, Johns Hopkins University School of Medicine, found that even if people walked as many as 20,000 steps a day, the health benefits continued to increase. They have not found an upper limit yet.

"Our study confirms that the more you walk, the better," says Prof. Banach. "We found that this applied to both men and women, irrespective of age, and irrespective of whether you live in a temperate, sub-tropical or sub-polar region of the world, or a region with a mixture of climates. In addition, our analysis indicates that as little as 4,000 steps a day are needed to significantly reduce deaths from any cause, and even fewer to reduce deaths from cardiovascular disease."

There is strong evidence that a sedentary lifestyle may contribute to an increase in cardiovascular disease and a shorter life. Studies have shown that insufficient physical activity affects more than a quarter of the world's population. More women than men (32% versus 23%), and people in higher income countries compared to low-income countries (37% versus 16%) do not undertake a sufficient amount of physical activity. According to World Health Organization data, insufficient physical activity is the fourth most frequent cause of death in the world, with 3.2 million deaths a year related to physical inactivity. The COVID-19 pandemic also resulted in a reduction in physical activity, and activity levels have not recovered two years on from it.

Dr Ibadete Bytyçi from the University Clinical Centre of Kosovo, Pristina, Kosovo, senior author of the paper, says: "Until now, it's not been clear what is the optimal number of steps, both in terms of the cut-off points over which we can start to see health benefits, and the upper limit, if any, and the role this plays in people's health. However, I should emphasise that there were limited data available on step counts up to 20,000 a day, and so these results need to be confirmed in larger groups of people."

This meta-analysis is the first not only to assess the effect of walking up to 20,000 steps a day, but also to look at whether there are any differences depending on age, sex or where in the world people live.

The studies analysed by the researchers followed up participants for a median (average) of seven years. The mean (average) age was 64, and 49% of participants were female.

In people aged 60 years or older, the size of the reduction in risk of death was smaller than that seen in people aged younger than 60 years. In the older adults, there was a 42% reduction in risk seen in those who walked between 6,000 and 10,000 steps a day, while there was a 49% reduction in risk in younger adults who walked between 7,000 and 13,000 steps a day.

Prof. Banach says: "In a world where we have more and more advanced drugs to target specific conditions such as cardiovascular disease, I believe we should always emphasise that lifestyle changes, including diet and exercise, which was a main hero of our analysis, might be at least as, or even more effective in reducing cardiovascular risk and prolonging lives. We still need good studies to investigate whether these benefits may exist for intensive types of exertion, such as marathon running and iron man challenges, and in different populations of different ages, and with different associated health problems. However, it seems that, as with pharmacological treatments, we should always think about personalising lifestyle changes."

Strengths of the meta-analysis include its size and that it was not restricted to looking at studies limited to a maximum of 16,000 steps a day. Limitations include that it was an observational study and so cannot prove that increased step counts cause the reduction in the risk of death, only that it is associated with it. The impact of step counts was not tested on people with different diseases; all the participants were generally healthy when they entered the studies analysed. The researchers were not able to account for differences in race and socioeconomic status, and the methods for counting steps were not identical in all the studies included in this meta-analysis.

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Researchers uncover why light-to-moderate drinking is tied to better heart health

A new study led by investigators from Massachusetts General Hospital, a founding member of the Mass General Brigham healthcare system, offers an explanation for why light-to-moderate alcohol consumption may be associated with lower risk of heart disease. For the first time, researchers found that alcohol, in light to moderate quantities, was associated with long-term reductions in stress signaling in the brain. This impact on the brain's stress systems appeared to significantly account for the reductions in cardiovascular events seen in light to moderate drinkers participating in the study. Findings are published in the Journal of the American College of Cardiology.

"We are not advocating the use of alcohol to reduce the risk of heart attacks or strokes because of other concerning effects of alcohol on health," says senior author and cardiologist Ahmed Tawakol, MD, co-director of the Cardiovascular Imaging Research Center at Massachusetts General Hospital. "We wanted to understand how light to moderate drinking reduces cardiovascular disease, as demonstrated by multiple other studies. And if we could find the mechanism, the goal would be to find other approaches that could replicate or induce alcohol's protective cardiac effects without the adverse impacts of alcohol."

Previous epidemiological studies have suggested that light to moderate alcohol consumption (1 drink per day for women and 1 to 2 drinks per day for men) is associated with a lower risk of cardiovascular disease. But it was unknown whether alcohol was inducing cardiovascular benefits, or whether light/moderate drinkers' health behaviors, socioeconomic status, or other factors protected their hearts.

The study, led by K Mezue and M Osborne, included more than 50,000 individuals enrolled in the Mass General Brigham Biobank. The first part of the study evaluated the relationship between light/moderate alcohol consumption and major adverse cardiovascular events after adjusting for a range of genetic, clinical, lifestyle, and socioeconomic confounders. The researchers found that light/moderate alcohol consumption was associated with a substantial reduction in the risk of cardiovascular disease events, even after accounting for those other factors.

Next, they studied a subset of 754 individuals who had undergone previous PET/CT brain imaging (primarily for cancer surveillance) to determine the effect of light/moderate alcohol consumption on resting stress-related neural network activity.

The brain imaging showed reduced stress signaling in the amygdala, the brain region associated with stress responses, in individuals who were light to moderate drinkers compared to those who abstained from alcohol or who drank little. And when the investigators looked at these individuals' history of cardiovascular events, they found fewer heart attacks and strokes in light to moderate drinkers. "We found that the brain changes in light to moderate drinkers explained a significant portion of the protective cardiac effects," says Tawakol.

It's long been known that alcohol reduces the amygdala's reactivity to threatening stimuli while individuals are drinking. The current study is the first to indicate that light to moderate alcohol consumption has longer-term neurobiological effects in dampening activity in the amygdala, which may have a significant downstream impact on the cardiovascular system.

"When the amygdala is too alert and vigilant, the sympathetic nervous system is heightened, which drives up blood pressure and increases heart rate, and triggers the release of inflammatory cells," explains Tawakol. "If the stress is chronic, the result is hypertension, increased inflammation, and a substantial risk of obesity, diabetes, and cardiovascular disease."

Finally, the investigators examined whether light/moderate alcohol would be even more effective at reducing heart attacks and strokes in people who are prone to a chronically higher stress response, such as those with a history of significant anxiety. They found that, within the 50,000-patient sample, light to moderate drinking was associated with nearly double the cardiac-protective effect in individuals with a history of anxiety compared with others.

Yet while light/moderate drinkers lowered their risk for cardiovascular disease, the study also showed that any amount of alcohol increases the risk of cancer. And at higher amounts of alcohol consumption -- more than 14 drinks a week -- heart attack risk started to increase while overall brain activity started to decrease (which may be associated with adverse cognitive health).

The authors concluded that research should focus on finding new interventions that reduce the brain's stress activity without the deleterious effects of alcohol. The research team is currently studying the effect of exercise, stress-reduction interventions such as meditation, and pharmacological therapies on stress-associated neural networks and how they might induce cardiovascular benefits.

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Being fit partially offsets negative impact of high blood pressure

High fitness levels may reduce the risk of death from cardiovascular disease in men with high blood pressure, according to a 29-year study published today in the European Journal of Preventive Cardiology, a journal of the ESC.

"This was the first study to evaluate the joint effects of fitness and blood pressure on the risk of dying from cardiovascular disease," said study author Professor Jari Laukkanen of the University of Eastern Finland, Kuopio, Finland. "The results suggest that being fit helps protect against some of the negative effects of high blood pressure."

Nearly 1.3 billion adults aged 30 to 79 years worldwide have high blood pressure (hypertension). Hypertension is a major risk factor for heart attack and stroke and a leading cause of premature death globally. Previous studies have shown that high cardiorespiratory fitness is linked with greater longevity. This study examined the interplay between blood pressure, fitness and risk of death from cardiovascular disease.

The study included 2,280 men aged 42 to 61 years living in eastern Finland and enrolled in the Kuopio Ischaemic Heart Disease Risk Factor Study. Baseline measurements were conducted between 1984 and 1989. These included blood pressure and cardiorespiratory fitness, which was assessed as maximal oxygen uptake while riding a stationary bicycle. Blood pressure was classified as normal or high, and fitness was classified as low, medium or high.

The average age at baseline was 53 years. Participants were followed up until 2018. During a median follow up of 29 years, there were 644 deaths due to cardiovascular disease. The risk of death from cardiovascular disease was analysed after adjusting for age, body mass index, cholesterol levels, smoking status, type 2 diabetes, coronary heart disease, use of antihypertensive medication, alcohol consumption, physical activity, socioeconomic status, and high sensitivity C-reactive protein (a marker of inflammation).

Considering blood pressure alone, compared to normal values, high blood pressure was associated with a 39% increased risk of cardiovascular mortality (hazard ratio [HR] 1.39; 95% confidence interval [CI] 1.17-1.63). Considering fitness alone, compared with high levels, low fitness was associated with a 74% elevated likelihood of cardiovascular death (HR 1.74; 95% CI 1.35-2.23).

To evaluate the joint associations of blood pressure and fitness with risk of cardiovascular death, participants were categorised into four groups: 1) normal blood pressure and high fitness (this was the reference group for comparison); 2) normal blood pressure and low fitness; 3) high blood pressure and high fitness; 4) high blood pressure and low fitness.

Men with high blood pressure and low fitness had a more than doubled risk of cardiovascular death compared to those with normal blood pressure and high fitness (HR 2.35; 95% CI 1.81-3.04). When men with high blood pressure had high fitness levels, their elevated risk of cardiovascular risk persisted but was weaker: it was 55% higher than those with normal blood pressure and high fitness (HR 1.55; 95% CI 1.16-2.07).

Professor Laukkanen said: "Both high blood pressure and low fitness levels were each associated with an increased risk of cardiovascular death. High fitness levels attenuated, but did not eliminate, the increased risk of cardiovascular mortality in men with elevated blood pressure."

The paper states: The inability of cardiorespiratory fitness to completely eliminate the risk of cardiovascular mortality in those with high blood pressure could partly be due to the strong, independent and causal relationship between blood pressure and cardiovascular disease.

Professor Laukkanen concluded: "Getting blood pressure under control should remain a goal in those with elevated levels. Our study indicates that men with high blood pressure should also aim to improve their fitness levels with regular physical activity. In addition to habitual exercise, avoiding excess body weight may enhance fitness."

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Heart health tip for older adults in 2023: Step it up a bit

The evidence-based health benefits of walking continue to accumulate, according to ongoing research by a University of Massachusetts Amherst physical activity epidemiologist, who leads an international consortium known as the Steps for Health Collaborative.

Findings from the latest study led by Amanda Paluch, assistant professor of kinesiology in the School of Public Health and Health Sciences, show that older adults who walked between 6,000 and 9,000 steps per day had a 40-50% reduced risk of a cardiovascular event, such as a heart attack or stroke, compared to those who walked 2,000 steps per day.

"We found for adults over 60, there was a strikingly lower risk of a cardiovascular event or disease over an average follow-up of six years," says Paluch, whose team's research was published this week in the journal Circulation. "When accumulating more steps per day, there was a progressively lower risk."

Earlier this year, research by Paluch and the Steps for Health Collaborative showed that more movement, even below the highly touted but unscientific "10,000 steps per day," was associated with longevity benefits. The meta-analysis of 15 studies involving nearly 50,000 people from four continents found that walking between 6,000 and 8,000 steps per day was linked with a lower risk of death from all causes among older adults.

Following those findings, Paluch and team wanted to tackle the less-charted territory of steps per day and cardiovascular disease. The results were similar, in terms of the most beneficial range of steps.

While there appears to be a continual additional benefit for those who walk more than 6,000 steps, Paluch says, encouraging the least-active older adults to take more steps is perhaps the most important public health message.

"The people who are the least active have the most to gain," she says. "For those who are at 2,000 or 3,000 steps a day, doing a little bit more can mean a lot for their heart health. If you're at 6,000 steps, getting to 7,000 and then to 8,000 also is beneficial, it's just a smaller, incremental improvement."

The meta-analysis of eight studies involved more than 20,000 people from the U.S. and 42 other countries. For younger adults, no link between steps per day and cardiovascular risk was detected.

"This is because cardiovascular disease is a disease of aging and often doesn't come to fruition until we're at older ages," says Paluch, whose project was supported by the Centers for Disease Control and Prevention (CDC). "You're not going to see many people develop cardiovascular disease after six years of follow-up in young to middle adulthood."

Future research involving younger adults and steps per day would focus on the precursors of cardiovascular disease, including high blood pressure, obesity and type 2 diabetes. "Those conditions develop in younger adults and are important for early prevention," Paluch says.

Four of the eight studies the researchers analyzed included data about walking intensity, or how fast the steps were taken. "We're interpreting these results with caution, but we did not find any striking association with walking intensity," she says. "There was no additional benefit with how fast you're walking, beyond the total number of steps that you accumulated."

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Positively charged nanomaterials treat obesity anywhere you want

Researchers have long been working on how to treat obesity, a serious condition that can lead to hypertension, diabetes, chronic inflammation, and cardiovascular diseases. Studies have also revealed a strong correlation of obesity and cancer -- recent data show that smoking, drinking alcohol, and obesity are the biggest contributors to cancer worldwide.

The development of fat cells, which are produced from a tiny fibroblast-like progenitor, not only activates the fat cells' specific genes but also grows them by storing more lipids (adipocytes and adipose tissue). In fact, lipid storage is the defining function of a fat cell. But the storage of too much lipid can make fat cells unhealthy and lead to obesity.

Challenges in targeting fat cells

The ability to target fat cells and safely uncouple unhealthy fat formation from healthy fat metabolism would be the answer to many peoples' prayers. A major challenge in obesity treatment is that fat tissue, which is not continuous in the body but is found piece by piece in "depots," has been difficult to target in a depot-specific manner, pinpointed at the exact location.

There are two main kinds of fat: visceral fat, internal tissues that surround the stomach, liver, and intestines, and subcutaneous fat, found under the skin anywhere in the body. Visceral fat produces potbellies; subcutaneous fat can create chin jowls, arm fat, etc. To date, there has been no way to specifically treat visceral adipose tissue. And current treatments for subcutaneous fat like liposuction are invasive and destructive.

New studies use cationic nanonmaterials to target fat

Two new studies from researchers at Columbia Engineering and Columbia University Irving Medical Center (CUIMC) may have the answer to targeting fat cells depot-specifically and healthily. The papers demonstrate a new method to treat obesity by using cationic nanomaterials that can target specific areas of fat and inhibit the unhealthy storage of enlarged fat cells. The materials remodel fat rather than destroying it, as, for example, liposuction does. The first paper, published today by Nature Nanotechnology, focuses on visceral adiposity, or belly fat. The second paper, published online November 28 by Biomaterials, focuses on fat underneath the skin as well as chronic inflammation associated with obesity.

The team of researchers, led by Li Qiang, associate professor of pathology and cell biology at CUIMC, and Kam Leong, Samuel Y. Sheng Professor of Biomedical Engineeringand of systems biology at CUIMC, recognized that adipose tissue contains large amounts of negatively charged extracellular matrix (ECM) to hold fat cells. They thought that this negatively charged ECM network might provide a highway system of sorts for positively charged molecules. So they took a positively charged nanomaterial, PAMAM generation 3 (P-G3), and injected it into obese mice. The P-G3 quickly spread throughout the tissue and the team was excited that their method to specifically target visceral fat worked.

Unexpected results

And then something intriguing happened: P-G3 shut off the lipid storage program in fat cells and the mice lost weight. This was totally unexpected, given the well-established function of P-G3 in neutralizing negatively charged pathogens, such as DNA/RNA cell debris, to alleviate inflammation.

"Our approach is unique -- It departs from the pharmacological or surgical approaches," says Qiang, who specializes in obesity and adipocyte biology. "We used cationic charge to rejuvenate healthy fat cells, a technique no one has ever used to treat obesity. I think this novel strategy will open the door to healthier and safer reduction of fat."

P-G3 helps new fat cell formation and also inhibits the unhealthy lipid storage of enlarged fat cells

In these two studies, the researchers discovered that the cationic material, P-G3, could do an intriguing thing to fat cells -- while it helped new fat cell formation, it also uncoupled lipid storage from the housekeeping functions of fat cells. And because it inhibits the unhealthy lipid storage of enlarged fat cells, the mice had more metabolically healthy, young, small fat cells like those found in newborns and athletes. The researchers found that this uncoupling function of P-G3 also holds true in human fat biopsies, signifying the potential of translation in humans.

"With P-G3, fat cells can still be fat cells, but they can't grow up," said Leong, a pioneer in using polycation to scavenge pathogens. "Our studies highlight an unexpected strategy to treat visceral adiposity and suggest a new direction of exploring cationic nanomaterials for treating metabolic diseases."

New applications for drug delivery, gene therapy, and aesthetics

Now that they can selectively target visceral fat, Leong and Qiang envision several applications. The Biomaterials study demonstrates a simple approach that could be used for aesthetic purposes; like Botox, P-G3 can be locally injected into a specific, subcutaneous fat depot. The investigators, who have patents pending, are now engineering P-G3 into various derivatives to improve the efficacy, safety, and depot specificity.

What the researchers are particularly excited about is developing P-G3 into a platform that can deliver drugs and gene therapies specifically to a given fat depot. This may repurpose many drugs from systemic safety concerns, such as Thiazolidinediones (TZDs), a potent but unsafe drug that is a strong modulator of fat and used to treat type 2 diabetes -- but it has been linked to heart failure and banned in several countries.

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Planting trees can save lives, study shows

In the past 30 years, the non-profit organization Friends of Trees planted trees along the streets of Portland, Oregon. Now, a new study shows that each tree planted was associated with significant reductions in non-accidental and cardiovascular mortality (of 20% and 6%, respectively, for trees planted in the preceding 15-30 years). The researchers also estimate that the annual economic benefits of planting trees greatly exceed the cost of maintaining them. The study, co-led by the Barcelona Institute for Global Health (ISGlobal), an institution supported by the "la Caixa" Foundation, together with the USDA Forest Service, was published in Environment International.

Evidence pointing to an association between exposure to nature and lower mortality is accumulating. "However, most studies use satellite imaging to estimate the vegetation index, which does not distinguish different types of vegetation and cannot be directly translated into tangible interventions," says Payam Dadvand, ISGlobal researcher and senior author of the study.

Thus, the authors took advantage of a natural experiment that took place in the city of Portland: between 1990 and 2019, Friends of Trees planted 49,246 street trees (and kept records of where the trees were planted, and when). So, the research team looked at the number of trees planted in a given area (specifically, a census track, where approximately 4,000 people live) in the preceding 5, 10 or 15 years. They associated this information with mortality due to cardiovascular, respiratory or non-accidental causes in that same area, using data from the Oregon Health Authority.

The results show that in neighbourhoods in which more trees had been planted, mortality rates (deaths per 100,000 persons) were lower. This negative association was significant for cardiovascular and non-accidental mortality (that is, all causes excluding accidents), particularly for males and people over the age of 65.

Furthermore, the association got stronger as trees aged and grew: the reduction in mortality rate associated with trees planted 11-15 years before (30%) was double that observed with trees planted in the preceding 1-5 years (15%). This means that older trees are associated with larger decreases in mortality, and that preserving existing mature trees may be particularly important for public health.

This study doesn't provide a direct insight into how trees improve health. However, the finding that large trees have a greater health impact than smaller ones is telling, because larger trees are better at absorbing air pollution, moderating temperatures, and reducing noise (three factors linked to increased mortality).

"We observed the effect both in green and less green neighbourhoods, which suggests that street tree planting benefits both," says Geoffrey H. Donovan, from the USDA Forest Service and first author of the study. The analysis took into account other factors that may influence mortality, such as income, education and racial composition of the neighbourhoods.

Finally, according to the authors' estimates, the benefits of tree planting greatly outweigh the cost: the annual cost of planting and maintaining one urban tree in each of Portland's 140 census tract areas would range somewhere between 3,000 and 13,000 USD, while it would generate around 14.2 million USD annually in lives saved.

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Good sleepers have lower risk of heart disease and stroke

Nine in ten people do not get a good night's sleep, according to research presented at ESC Congress 2022.1 The study found that suboptimal sleep was associated with a higher likelihood of heart disease and stroke. The authors estimated that seven in ten of these cardiovascular conditions could be prevented if everyone was a good sleeper.

"The low prevalence of good sleepers was expected given our busy, 24/7 lives," said study author Dr. Aboubakari Nambiema of INSERM (the French National Institute of Health and Medical Research), Paris, France. "The importance of sleep quality and quantity for heart health should be taught early in life when healthy behaviours become established. Minimising night-time noise and stress at work can both help improve sleep."

Previous studies on sleep and heart disease have generally focused on one sleep habit, such as sleep duration or sleep apnoea, where breathing stops and starts while sleeping. In addition, prior studies have often assessed sleep at baseline only. The current study used a healthy sleep score combining five sleep habits. The researchers investigated the association between the baseline sleep score, and changes over time in the sleep score, and incident cardiovascular disease.

This study included 7,200 participants of the Paris Prospective Study III (PPP3), an observational community-based prospective cohort. Men and women aged 50 to 75 years and free of cardiovascular disease were recruited in a preventive medical centre between 2008 and 2011. The average age was 59.7 years and 62% were men. Participants underwent a physical examination and completed questionnaires on lifestyle, personal and family medical history, and medical conditions.

Questionnaires were used to collect information on five sleep habits at baseline and two follow up visits. Each factor was given 1 point if optimal and 0 if not. A healthy sleep score ranging from 0 to 5 was calculated, with 0 or 1 considered poor and 5 considered optimal. Those with an optimal score reported sleeping 7 to 8 hours per night, never or rarely having insomnia, no frequent excessive daytime sleepiness, no sleep apnoea, and an early chronotype (being a morning person). The researchers checked for incident coronary heart disease and stroke every two years for a total of 10 years.

At baseline, 10% of participants had an optimal sleep score and 8% had a poor score. During a median follow up of eight years, 274 participants developed coronary heart disease or stroke. The researchers analysed the association between sleep scores and cardiovascular events after adjusting for age, sex, alcohol consumption, occupation, smoking, body mass index, physical activity, cholesterol level, diabetes, and family history of heart attack, stroke or sudden cardiac death. They found that the risk of coronary heart disease and stroke decreased by 22% for every 1 point rise in the sleep score at baseline. More specifically, compared to those with a score of 0 or 1, participants with a score of 5 had a 75% lower risk of heart disease or stroke.

The researchers estimated the proportion of cardiovascular events that could be prevented with healthier sleep. They found that if all participants had an optimal sleep score, 72% of new cases of coronary heart disease and stroke might be avoided each year.

Over two follow ups, almost half of participants (48%) changed their sleep score: in 25% it decreased whereas in 23% it improved. When the researchers examined the association between the change in score and cardiovascular events, they found that a 1 point increment over time was associated with a 7% reduction in the risk of coronary heart disease or stroke.

Dr. Nambiema said: "Our study illustrates the potential for sleeping well to preserve heart health and suggests that improving sleep is linked with lower risks of coronary heart disease and stroke. We also found that the vast majority of people have sleep difficulties. Given that cardiovascular disease is the top cause of death worldwide, greater awareness is needed on the importance of good sleep for maintaining a healthy heart."

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Sleepless and selfish: Lack of sleep makes us less generous

Humans help each other -- it's one of the foundations of civilized society. But a new study by scientists at the University of California, Berkeley, reveals that a lack of sleep blunts this fundamental human attribute, with real-world consequences.

Lack of sleep is known to be associated with an increased risk of cardiovascular disease, depression, diabetes, hypertension and overall mortality. However, these new discoveries show that a lack of sleep also impairs our basic social conscience, making us withdraw our desire and willingness to help other people.

In one portion of the new study, the scientists showed that charitable giving in the week after the beginning of Daylight Saving Time, when residents of most states "spring forward" and lose one hour of their day, dropped by 10% -- a decrease not seen in states that do not change their clocks or when states return to standard time in the fall.

The study, led by UC Berkeley research scientist Eti Ben Simon and Matthew Walker, a UC Berkeley professor of psychology, adds to a growing body of evidence demonstrating that inadequate sleep not only harms the mental and physical well-being of an individual, but also compromises the bonds between individuals -- and even the altruistic sentiment of an entire nation.

"Over the past 20 years, we have discovered a very intimate link between our sleep health and our mental health. Indeed, we've not been able to discover a single major psychiatric condition in which sleep is normal," Walker said. "But 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. How we operate as a social species -- and we are a social species -- seems profoundly dependent on how much sleep we are getting."

"We're starting to see more and more studies, including this one, where the effects of sleep loss don't just stop at the individual, but propagate to those around us," said Ben Simon. "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, Walker and colleagues Raphael Vallat and Aubrey Rossi will publish their results August 23 in the open access journal PLOS Biology. Walker is the director of the Center for Human Sleep Science. He and Ben Simon are members of the Helen Wills Neuroscience Institute at UC Berkeley.

Sleeplessness dampens theory of mind network

The new report describes three separate studies that assessed the impact of sleep loss on people's willingness to help others. In the first study, the scientists placed 24 healthy volunteers in a functional magnetic resonance imager (fMRI) to scan their brains after eight hours of sleep and after a night of no sleep. They found that areas of the brain that form the theory of mind network, which is engaged when people empathize with others or try to understand other people's wants and needs, were less active after a sleepless night.

"When we think about other people, this 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."

In a second study, they tracked more than 100 people online over three or four nights. During this time, the researchers measured the quality of their sleep -- how long they slept, how many times they woke up -- and then assessed their desire to help others, such as holding an elevator door open for someone else, volunteering or helping an injured stranger on the street.

"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."

The third part of the study involved mining a database of 3 million charitable donations in the United States between 2001 and 2016. Did the number of donations change after the transition to Daylight Saving Time and the potential loss of an hour of sleep? They found a 10% drop in donations. This same dent in compassionate gift-giving was not seen in regions of the country that did not change their clocks.

"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."

An earlier study by Walker and Ben Simon showed that sleep deprivation forced people to socially withdraw and become more socially isolated. A lack of sleep also increased their feelings of loneliness. Worse still, when those sleep-deprived individuals interacted with other people, they spread their loneliness to those other individuals, almost like a virus, Walker said.

"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," he said. "A lack of sleep makes people less empathetic, less generous, more socially withdrawn, and it's infectious -- there is contagion of loneliness."

"The realization that the quantity and quality of sleep affects an entire society, caused by an impairment in prosocial behavior, may provide insights into our societal state of affairs in the present day," Walker added.

This finding also offers a novel approach to improving these specific aspects of our society.

"Promoting sleep, rather than shaming people for sleeping enough, could very palpably help shape the social bonds we all experience every day," Ben Simon said.

"Sleep, it turns out, is an incredible lubricant to prosocial, connected, empathic, kind and generous human behavior. 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," said Walker, author of the international bestseller, Why We Sleep. "Sleep may be a wonderful ingredient that enables the alacrity of helping between human beings."

"Sleep is essential for all aspects of our physical, mental and emotional lives," Ben Simon said. "When sleep is undervalued in society, not only do we get sleep-deprived doctors, nurses and students, but we also suffer from unkind and less empathic interactions on a daily basis."

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