Tag: exercise

Firefighter Study Reveals how Extreme Exercise can Suppress the Immune System

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A study of firefighters on a punishing training course has revealed clues as to why extreme exercise temporarily weakens the immune system – a phenomenon seen in elite athletes. The findings, published in Military Medical Research, may lead to better ways to support the health of people who undergo extreme exertion, such as firefighters tackling wildfires.

Thirteen firefighters volunteered for the study, average age 25 and male. They went through a rigorous training exercise, carrying 9 to 20kg of gear over hilly terrain during a 45-minute training exercise in the California sun. Gloves, helmets, flashlights, goggles, and more weighted them down as they sprinted through the countryside wearing fire-resistant clothing to show they were ready to serve as wildland firefighters.

After the training, they immediately gave samples of their blood, saliva, and urine for analysis. Two were excluded, one being unable to finish the course and the other arriving to late to provide a sample. The 11 participants who completed the course lost an average of 2.2% of their initial weight.

Then, the scientists from the Department of Energy’s Pacific Northwest National Laboratory (PNNL) analysed more than 4700 molecules, consisting of proteins, lipids, and metabolites, from each of the firefighters, looking to understand what happens when the body undergoes intense physical exercise. Measuring and interpreting the data from thousands of such measurements is a specialty of PNNL scientists who explore issues related to climate science and human health by analysing millions of sensitive measurements using mass spectrometry each year.

The researchers’ aim was to increase safety for first responders and others.

“Heat stress can be life threatening,” said Kristin Burnum-Johnson, a corresponding author of the study. “We wanted to take an in-depth look at what’s happening in the body and see if we’re able to detect danger from exhaustion in its earliest stages. Perhaps we can reduce the risk of strenuous exercise for first responders, athletes, and members of the military.”

As expected, the team detected hundreds of molecular changes in the firefighters. The differences before and after exercise underscored the body’s efforts at tissue damage and repair, maintenance of fluid balance, efforts to keep up with increased energy and oxygen demand, and the body’s attempts to repair and regenerate its proteins and other important substances.

But in the saliva, the team found some unexpected results. There was a change in the microbial mix of the mouth – the oral microbiome – showing that the body was increasingly on the lookout for bacterial invaders. Scientists also saw a decrease in signaling molecules important for inflammation and for fighting off viral infections.

A decrease in inflammation makes sense for people exercising vigorously; less inflammation allows people to breathe in air more quickly, meeting the body’s eager demand for more oxygen. Having fewer inflammatory signals in the respiratory system helps the body improve respiration and blood flow.

Less inflammation, more inhalation

But less inflammation leaves the body more vulnerable to viral respiratory infection, which other studies observed in elite athletes and others who exercise vigorously. Some studies have shown that a person is up to twice as likely to come down with a viral respiratory infection in the days after an especially energetic workout.

“People who are very fit might be more prone to viral respiratory infection immediately after vigorous exercise. Having less inflammatory activity to fight off an infection could be one cause,” said Ernesto Nakayasu, a corresponding author of the paper. He notes that the work provides a molecular basis for what clinicians have noticed in their patients who do strenuous workouts.

The team hopes that the findings will help explain why come people are more vulnerable to respiratory infection after a workout.

Source: DOE/Pacific Northwest National Laboratory

Review Identifies Most Effective Forms of Exercise to Reduce Blood Pressure

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A meta-analysis published in the British Journal of Sports Medicine has shown that isometric exercises, which involve contracting muscles to hold the body in position without moving such as in wall squats, are best for reducing resting blood pressure. The researchers reviewed 270 randomised clinical trials with a total of 15 827 participants.

All of the studies included measured blood pressure after two weeks or more of exercise intervention, and included non-intervention control groups. It was found that isometric exercises reduced systolic and diastolic blood pressure by 8.24 and 4.00mmHg respectively. The next most effective forms of training in reducing blood pressure were combined training, followed by dynamic resistance training, aerobic exercise, and high-intensity interval training (HIIT).

The researchers noted that current guidelines are based on older research and as such don’t include data from new forms of exercise such as HIIT. These guidelines tend to emphasise aerobic training such as running for controlling blood pressure. In addition to helping clinicians optimise individualised exercise recommendations, the new findings suggest that it might be time to update exercise guidelines for preventing and treating high blood pressure.

Source: JAMA Network

Meal Skipping, Diet Prescription Pills Least Effective Weight Loss Habits

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A new study in the Journal of the American Heart Association links a healthier diet and increased exercise to weight loss that reduces heart disease risk – while associating skipping meals and taking prescription diet pills with minimal weight loss, weight maintenance or weight gain.

For many in the study sample of more than 20 000, losing a “clinically significant” 5% of their body weight did not eliminate their risk factors for cardiovascular disease, results showed. In fact, the average composite score on eight risk factors for heart disease was the same across the entirety of the study population – regardless of weight loss or gain.

The study is the first to compare weight-loss strategies and results in the context of the American Heart Association’s “Life’s Essential 8,” a checklist promoting heart disease risk reduction through the pursuit of recommended metrics for body weight, blood pressure, cholesterol, blood sugar, smoking, physical activity, diet and sleep.

The Ohio State University researchers found that overall, US adults had an average score of 60 out of 100 on the Essential 8 suggesting there is plenty of room for improvement even among those whose diet and exercise behaviours helped move the needle on some metrics.

“The Life’s Essential 8 is a valuable tool that provides the core components for cardiovascular health, many of which are modifiable through behaviour change,” said senior study author Colleen Spees, associate professor of medical dietetics in the School of Health and Rehabilitation Sciences at Ohio State.

“Based on the findings in this study, we have a lot of work to do as a country,” she said. “Even though there were significant differences on several parameters between the groups, the fact remains that as a whole, adults in this country are not adopting the Life’s Essential 8 behaviours that are directly correlated with heart health.”

Data for the analysis came from 20 305 U.S. adults aged 19 or older (average age of 47) who participated in the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2016. Participants reported their smoking status, physical activity, average hours of sleep per night, weight history and weight loss strategy, and what they had eaten in the previous 24 hours. Health exams and lab tests measured their body mass index, blood pressure, LDL (bad) cholesterol and blood glucose.

The Ohio State researchers used the data to determine individuals’ values for Life’s Essential 8 metrics and assessed their diet quality according to the Healthy Eating Index, which gauges adherence to US Dietary Guidelines for Americans.

Of the sample, 17 465 participants had lost less than 5% of their body weight, maintained their weight or gained weight in the past year. The remaining 2840 reported intentional loss of at least 5% of their body weight in the same time frame.

“Clinically significant weight loss results in improvements in some health indices,” Spees said. “People should feel hopeful in knowing that losing just 5% of their body weight is meaningful in terms of clinical improvements. This is not a huge weight loss. It’s achievable for most, and I would hope that incentives people instead of being paralysed with a fear of failure.”

In this study, adults with clinically significant weight loss reported higher diet quality, particularly with better scores on intakes of protein, refined grains and added sugar, as well as more moderate and vigorous physical activity and lower LDL cholesterol than the group without clinically significant weight loss. On the other hand, the weight-loss group also had a higher average BMI and HbA1c blood sugar measure and fewer hours of sleep – all metrics that would bring down their composite Life’s Essential 8 score.

A greater proportion of people who did not lose at least 5% of their weight reported skipping meals or using prescription diet pills as weight-loss strategies. Additional strategies reported by this group included low-carb and liquid diets, taking laxatives or vomiting, and smoking.

“We saw that people are still gravitating to non-evidence-based approaches for weight loss, which are not sustainable. What is sustainable is changing behaviours and eating patterns,” Spees said.

Source: Ohio State University

Strenuous Jobs Increase Men’s Cardiovascular Risk, but Reduce Women’s

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A long-term Danish study found that high physical activity at work was associated with higher risk of ischaemic heart disease (IHD) in men, but in women, this was associated with lower risk. The findings, published in the European Journal of Preventive Cardiology, highlight the importance of taking gender into account when considering the impact of high levels of occupational physical activity (OPA).

While previous studies have shown that physical activities in leisure time are protective against cardiovascular disease, high levels of OPA were shown to have no benefit – or even a detrimental effect.

The study followed up participants aged 30–61 years old after 34 years who took part in the Danish Monica 1 study in 1982–84. Participants, 1399 women and 1706 men, were actively employed, without prior IHD and who answered a question on OPA. The participants’ medical records were located in the Danish National Patient Registry and the researchers analysed the data, controlling for increasing numbers of factors such as age, then age and sex, and then age and sex plus factors such as smoking.

Compared to women doing sedentary work, women in all other OPA categories had a lower hazard ratio (HR) for IHD. Among men, the risk of IHD was 22% higher among those with light OPA, and 42% and 46% higher among those with moderate OPA with some lifting or strenuous work with heavy lifting, respectively, compared to men with sedentary OPA. Compared to women with sedentary work, HR for IHD was higher among men in all OPA categories, and a statistically significant interaction between OPA and sex was found.

Demanding or strenuous OPA seems to be a risk factor for IHD among men, whereas a higher level of OPA seems to protect from IHD among women. The researchers wrote that this underlines the importance of taking into account sex differences in studies of health effects of OPA. Future studies should investigate the underlying mechanisms for this difference, such as differences in exposure and physiology.

Walking 11 Minutes a Day Could Prevent 1 in 10 Early Deaths

One in ten early deaths could be prevented if everyone managed at least half the recommended level of physical activity, say a team led by researchers at the University of Cambridge.

In a study published today in the British Journal of Sports Medicine, the researchers say that 11 minutes a day (75 minutes a week) of moderate-intensity physical activity – such as a brisk walk – would be sufficient to lower the risk of diseases such as heart disease, stroke and a number of cancers.

Cardiovascular diseases – such as heart disease and stroke – are the leading cause of death globally, responsible for 17.9 million deaths per year in 2019, while cancers were responsible for 9.6 million deaths in 2017. Physical activity – particularly when it is moderate-intensity – is known to reduce the risk of cardiovascular disease and cancer, and the NHS recommends that adults do at least 150 minutes of moderate-intensity activity or 75 minutes of vigorous-intensity activity a week.

To explore the amount of physical activity necessary to have a beneficial impact on several chronic diseases and premature death, researchers from the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge carried out a systematic review and meta-analysis, pooling and analysing cohort data from all of the published evidence. This approach allowed them to bring together studies that on their own did not provide sufficient evidence and sometimes disagreed with each other to provide more robust conclusions.

In total, they looked at results reported in 196 peer-reviewed articles, covering more than 30 million participants from 94 large study cohorts, to produce the largest analysis to date of the association between physical activity levels and risk of heart disease, cancer, and early death.

The researchers found that, outside of work-related physical activity, two out of three people reported activity levels below 150 min per week of moderate-intensity activity and fewer than one in ten managed more than 300 min per week.

Broadly speaking, they found that beyond 150 min per week of moderate-intensity activity, the additional benefits in terms of reduced risk of disease or early death were marginal. But even half this amount came with significant benefits: accumulating 75 min per week of moderate-intensity activity brought with it a 23% lower risk of early death.

Dr Soren Brage from the MRC Epidemiology Unit said: “If you are someone who finds the idea of 150 minutes of moderate-intensity physical activity a week a bit daunting, then our findings should be good news. Doing some physical activity is better than doing none. This is also a good starting position – if you find that 75 minutes a week is manageable, then you could try stepping it up gradually to the full recommended amount.”

Seventy-five minutes per week of moderate activity was also enough to reduce the risk of developing cardiovascular disease by 17% and cancer by 7%. For some specific cancers, the reduction in risk was greater – head and neck, myeloid leukaemia, myeloma, and gastric cardia cancers were between 14 and 26% lower risk. For other cancers, such as lung, liver, endometrial, colon, and breast cancer, a 3–11% lower risk was observed.

Professor James Woodcock from the MRC Epidemiology Unit said: “We know that physical activity, such as walking or cycling, is good for you, especially if you feel it raises your heart rate. But what we’ve found is there are substantial benefits to heart health and reducing your risk of cancer even if you can only manage 10 minutes every day.”

The researchers calculated that if everyone in the studies had done the equivalent of at least 150 min per week of moderate-intensity activity, around one in six (16%) early deaths would be prevented. One in nine (11%) cases of cardiovascular disease and one in 20 (5%) cases of cancer would be prevented.

However, even if everyone managed at least 75 min per week of moderate-intensity physical activity, around one in ten (10%) early deaths would be prevented. One in twenty (5%) cases of cardiovascular disease and nearly one in thirty (3%) cases of cancer would be prevented.

Source: Cambridge University

Exercise for Managing Depression has Greater Efficacy than Meds or Counselling

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University of South Australia researchers are calling for exercise to be a mainstay approach for managing depression as a new study shows that physical activity is 1.5 times more effective than counselling or the leading medications.

Published in the British Journal of Sports Medicine, the review is the most comprehensive to date, encompassing 97 reviews, 1039 trials and 128 119 participants. It shows that physical activity is extremely beneficial for improving symptoms of depression, anxiety, and distress.

Specifically, the review showed that exercise interventions that were 12 weeks or shorter were the most effective at reducing mental health symptoms, highlighting the speed at which physical activity can make a change.

The largest benefits were seen among people with depression, pregnant and postpartum women, healthy individuals, and people diagnosed with HIV or kidney disease.

According to the World Health Organization, one in every eight people worldwide (970 million people) live with a mental disorder

Lead UniSA researcher, Dr Ben Singh, says physical activity must be prioritised to better manage the growing cases of mental health conditions.

“Physical activity is known to help improve mental health. Yet despite the evidence, it has not been widely adopted as a first-choice treatment,” Dr Singh says.

“Our review shows that physical activity interventions can significantly reduce symptoms of depression and anxiety in all clinical populations, with some groups showing even greater signs of improvement.

“Higher intensity exercise had greater improvements for depression and anxiety, while longer durations had smaller effects when compared to short and mid-duration bursts.

“We also found that all types of physical activity and exercise were beneficial, including aerobic exercise such as walking, resistance training, Pilates, and yoga.

“Importantly, the research shows that it doesn’t take much for exercise to make a positive change to your mental health.”

Senior researcher, UniSA’s Prof Carol Maher, says the study is the first to evaluate the effects of all types of physical activity on depression, anxiety, and psychological distress in all adult populations.

“Examining these studies as a whole is an effective way for clinicians to easily understand the body of evidence that supports physical activity in managing mental health disorders.

“We hope this review will underscore the need for physical activity, including structured exercise interventions, as a mainstay approach for managing depression and anxiety.”

Source: University of South Australia

More Physical Activity Linked to Fewer Respiratory Infections in Children

Boys running
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A study of 104 children wearing pedometers to monitor daily activity showed that higher levels of physical activity are associated with reduced susceptibility to upper respiratory tract infections such as the common cold. Reporting the findings in Pediatric Research, the researchers suggest reduced inflammatory cytokines and improved immune responses as a possible mechanism.

Wojciech Feleszko, Katarzyna Ostrzyżek-Przeździecka and colleagues measured the physical activity levels and symptoms of upper respiratory tract infections of children aged between four and seven years in the Warsaw city region between 2018 and 2019. Participants wore a pedometer armband 24 hours a day for 40 days to measure their activity levels and sleep duration. For 60 days, parents used daily questionnaires to report their children’s symptoms of upper respiratory tract infections, such as coughing or sneezing. On a second questionnaire, parents reported their children’s vaccinations, participation in sport, whether they had siblings, and their exposure to smoking and pet hair.

The authors found that as the average daily number of steps taken by children throughout the study period increased by 1000, the number of days that they experienced symptoms of upper respiratory tract infections decreased by an average of 4.1 days. Additionally, children participating in three or more hours of sport per week tended to experience fewer days with respiratory tract infection symptoms than those not regularly participating in sports.

Higher activity levels at the beginning of the study were associated with fewer days with respiratory tract infection symptoms during the following six weeks. Among 47 children, with 5668 average daily steps during the first two weeks of the study period, the combined number of days during the following six weeks that these children experienced upper respiratory tract infection symptoms was 947. However, among 47 children whose initial average daily steps numbered 9368, the combined number of days during the following six weeks that these children experienced respiratory symptoms for was 724. Upper respiratory tract infection symptoms were not associated with sleep duration, siblings, vaccinations, or exposure to pet hair or smoking.

The authors speculate that higher physical activity levels could help reduce infection risk in children by reducing levels of inflammatory cytokines and by promoting immune responses involving T-helper cells. They also suggest that skeletal muscles could release small extracellular vesicles that modulate immune responses following exercise. However, they caution that future research is needed to investigate these potential mechanisms in children. In addition, since this was an observational study, causality could not be established.

Source: EurekAlert!

Fixing Prolonged Sitting: Five Minutes’ Walking every Half Hour

While evidence suggests that prolonged sitting is hazardous to health, the optimum interval and quantity for exercise breaks has been unclear. Now, exercise physiologists can provide an answer: just five minutes of walking every half hour during periods of prolonged sitting can offset some of the most harmful effects.

The study, led by Keith Diaz, PhD, associate professor of behavioral medicine at Columbia University Vagelos College of Physicians and Surgeons, was published online in Medicine & Science in Sports & Exercise.

Unlike other studies that test one or two activity options, Diaz’s study tested five different exercise ‘snacks’: one minute of walking after every 30 minutes of sitting, one minute after 60 minutes; five minutes every 30; five minutes every 60; and no walking.

“If we hadn’t compared multiple options and varied the frequency and duration of the exercise, we would have only been able to provide people with our best guesses of the optimal routine,” Diaz says.

Each of the 11 adults who participated in the study came to Diaz’s laboratory, where participants sat in an ergonomic chair for eight hours, rising only for their prescribed exercise snack of treadmill walking or a bathroom break. Researchers kept an eye on each participant to ensure they did not over- or under-exercise and periodically measured the participants’ blood pressure and blood sugar (key indicators of cardiovascular health). Participants were allowed to work on a laptop, read, and use their phones during the sessions and were provided standardized meals.

The optimal amount of movement, the researchers found, was five minutes of walking every 30 minutes. This was the only amount that significantly lowered both blood sugar and blood pressure. In addition, this walking regimen had a dramatic effect on how the participants responded to large meals, reducing blood sugar spikes by 58% compared with sitting all day.

Taking a walking break every 30 minutes for one minute also provided modest benefits for blood sugar levels throughout the day, while walking every 60 minutes (either for one minute or five minutes) provided no benefit.

All amounts of walking significantly reduced blood pressure by 4 to 5 mmHg compared with sitting all day. “This is a sizeable decrease, comparable to the reduction you would expect from exercising daily for six months,” says Diaz.

The researchers also periodically measured participants’ levels of mood, fatigue, and cognitive performance during the testing. All walking regimens, except walking one minute every hour, led to significant decreases in fatigue and significant improvements in mood. None of the walking regimens influenced cognition.

“The effects on mood and fatigue are important,” Diaz says. “People tend to repeat behaviors that make them feel good and that are enjoyable.”

The Columbia researchers are currently testing 25 different doses of walking on health outcomes and testing a wider variety of people: Participants in the current study were in their 40s, 50s, and 60s, and most did not have diabetes or high blood pressure.

“What we know now is that for optimal health, you need to move regularly at work, in addition to a daily exercise routine,” says Diaz. “While that may sound impractical, our findings show that even small amounts of walking spread through the work day can significantly lower your risk of heart disease and other chronic illnesses.”

Source: Columbia University Irving Medical Center

Exercise Improves Quality of Life in Breast Cancer Radiotherapy

Tired woman after exercise
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Radiotherapy is an important part of breast cancer treatment but can lead to cancer-related fatigue and negatively impact patients’ health-related quality of life. Fortunately, latest research by has revealed exercise may make radiotherapy more tolerable for patients, offering benefits for their emotional, physical and social wellbeing.

Researchers at Edith Cowan University (ECU) included 89 women in the study, with 43 completing a home-based 12-week program, consisting of a weekly exercise regime of one to two resistance training sessions and an accumulated 30–40 minutes of aerobic exercise. The 46 controls did not participate in the exercise regime.

The results, published in Breast Cancer, showed that patients who exercised recovered from cancer-related fatigue quicker during and after radiotherapy compared to the control group and saw a significant increase in health-related quality of life post radiotherapy with no reported adverse effects.

Study supervisor Professor Rob Newton said this showed home-based resistance and aerobic exercise during radiotherapy is safe, feasible and effective in accelerating recovery from cancer-related fatigue and improving health-related quality of life.

“A home-based protocol might be preferable for patients, as it is low-cost, does not require travel or in-person supervision and can be performed at a time and location of the patient’s choosing,” he said.

“These benefits may provide substantial comfort to patients.”

Important changes observed

Australia’s current national guidelines for cancer patients recommend moderately intense aerobic exercise for 30 minutes per day, five days a week, or vigorously intense aerobic exercise for 20 minutes a day for three days a week.

They also call for 8–10 strength-training exercises with 8–12 repetitions per exercise, for two-to-three days per week.

However, study lead Dr Georgios Mavropalias said benefits were still observed with less exercise.

“The amount of exercise was aimed to increase progressively, with the ultimate target of participants meeting the national guideline for recommended exercise levels,” he said.

“However, the exercise programmes were relative to the participants’ fitness capacity, and we found even much smaller dosages of exercise than those recommended in the national guidelines can have significant effects on cancer-related fatigue and health-related quality of living during and after radiotherapy.”

The study also found participants good adherence to exercise programmes once they started. The exercise group reported significant improvements in mild, moderate and vigorous physical activity up to 12 months after the supervised exercise programme finished.

“The exercise programme in this study seems to have induced changes in the participants’ behaviour around physical activity,” Dr Mavropalias said.

“Thus, apart from the direct beneficial effects on reduction in cancer-related fatigue and improving health-related quality of life during radiotherapy, home-based exercise protocols might result in changes in the physical activity of participants that persist well after the end of the program.”

Source: Edith Cowan University

Lasting Benefits from Swapping 30 Minutes of Social Media for Exercise

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In a study in the Journal of Public Health, participants who exchanged 30 minutes of social media use per day for exercise felt happier, more satisfied, less stressed by the COVID pandemic and less depressed than a control group. These effects persisted even six months after the study had ended.

The downside of social media

While it helped people stay connected during the COVID pandemic, social media consumption has also its drawbacks. Heavy use can lead to addictive behaviour that manifests itself in, for example, a close emotional bond to the social media. In addition, fake news and conspiracy theories can spread uncontrollably on social channels and trigger even more anxiety.

“Given that we don’t know for certain how long the coronavirus crisis will last, we wanted to know how to protect people’s mental health with services that are as free and low-threshold as possible,” explained assistant professor Dr. Julia Brailovskaia, who lead a team from the Mental Health Research and Treatment Center at Ruhr-Universität Bochum. To find out whether the type and duration of social media use can contribute to this, she and her team conducted an experimental study, with a total of 642 participants randomised to one of four groups.

A two-week experiment

The first group reduced the daily social media consumption by 30 minutes during an intervention period of two weeks. Since previous studies had shown that physical activity can increase well-being and reduce depressive symptoms, the second group increased the duration of physical activity by 30 minutes daily during this period, while continuing to use social media as usual. The third group combined both, reducing social media use and increasing physical activity. A control group didn’t change the behaviour during the intervention phase.

Before, during and up to six months after the two-week intervention phase, the participants responded to online surveys on the duration, intensity and emotional significance of their social media use, physical activity, their satisfaction with life, their subjective feeling of happiness, depressive symptoms, the psychological burden of the COVID pandemic and their cigarette consumption.

Healthy and happy in the age of digitalisation

The findings clearly showed that both reducing the amount of time spent on social media each day and increasing physical activity have a positive impact on people’s well-being. The combination of the two interventions in particular increases one’s satisfaction with life and subjective feeling of happiness and reduces depressive symptoms. Even six months after the two-week intervention phase had ended, participants in all three intervention groups spent less time on social media than before: about a half hour in the groups that had either reduced social media time or increased their daily exercise, and about three-quarters of an hour in the group that had combined both measures. Six months after the intervention, the combination group engaged one hour and 39 minutes more each week in physical activity than before the experiment. The positive influence on mental health continued throughout the entire follow-up period.

“This shows us how vital it is to reduce our availability online from time to time and to go back to our human roots,” Julia Brailovskaia concluded. “These measures can be easily implemented into one’s everyday life and they’re completely free — and, at the same time, they help us to stay happy and healthy in the digital age.”

Source: Ruhr-University Bochum