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EXPERT REACTION A bit of exercise a day keeps the death away

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People who do half an hour of exercise, five times a week have a much lower risk of death and heart disease, according to an international study. Looking at data from over 130,000 people, the researchers suggest 30 minutes of exercise could potentially prevent one in 12 deaths and one in 20 cases of heart disease globally. If five sessions in the gym sounds unmanageable, the researchers say physical jobs and household chores are good enough to count.

Journal/conference: The Lancet

Organisation/s: Simon Fraser University, Canada

Media Release

From: The Lancet

The Lancet: Globally, one in 12 deaths could be prevented with 30 mins physical activity five days a week

Study also finds that 1 in 20 cases of cardiovascular disease could be prevented if everyone did 30 mins physical activity five days a week – whether it’s going to the gym, walking to work, or household chores

Completing 30 minutes of physical activity five days a week (150 mins a week) is associated with a reduced risk of death and cardiovascular disease, according to the largest study of physical activity tracking 130000 people in 17 countries published in The Lancet.

Being highly active (750 mins a week) is associated with an even greater reduction, and the authors found that this was more achievable for those who built physical activity into their day through active transport, job type, or housework.

The study confirms on a global scale that physical activity is associated with a lower risk of mortality and cardiovascular disease (including death from cardiovascular disease, heart attack, stroke, or heart failure), irrespective of a person’s home country, other risk factors for disease, the type of physical activity and whether the activity is for leisure or if it is taken as part of daily transport, at work, or housework.

The World Health Organisation (WHO) recommend that adults aged 18-64 years old do at least 150 minutes of moderate-intensity aerobic physical activity throughout the week, as well as muscle strengthening exercises at least two days a week [1]. But estimates suggest that almost a quarter (23%) of the world’s population are not meeting physical activity guidelines.

Previous research into the benefits of physical activity has generally focussed on high-income countries, while research in low- and middle-income countries has been limited. Typically, studies also focus on exercise in leisure time, which is less common in lower-income countries.

“Meeting physical activity guidelines by walking for as little as 30 minutes most days of the week has a substantial benefit, and higher physical activity is associated with even lower risks,” says lead author Dr Scott Lear, Professor of Simon Fraser University’s Faculty of Health Sciences and Pfizer/Heart & Stroke Foundation Chair in Cardiovascular Prevention Research at St. Paul’s Hospital in Canada. “The affordability of other cardiovascular disease interventions, such as generic drugs and consuming fruits and vegetables, are often beyond the reach of many people in low-income and middle-income countries. However, physical activity represents a low cost approach to preventing cardiovascular disease, and our study provides robust evidence to support public health interventions to increase all forms of physical activity in these regions.” [2]

Cardiovascular disease is the leading cause of death worldwide and a major economic burden globally. It is estimated that 70% of cardiovascular disease deaths occur in low- and middle-income countries, where it is the most common cause of death.

In the study, 130843 participants aged 35-70 years old from urban and rural areas in 17 countries across various world regions [3] completed questionnaires on their levels of physical activity.

At the start of the study, each participant provided information on their socioeconomic status, lifestyle behaviours, medical history, family history of cardiovascular disease, weight, height, waist and hip measurements, and blood pressure. They also completed a questionnaire on the types of physical activity they completed over a typical week, which the researchers used to calculate their average activity levels.

Participants completed follow-up visits with the research team at least every three years to record information on cardiovascular disease and death for 6.9 years. The team analysed rates of cardiovascular events (including death from cardiovascular disease, heart attack, stroke, or heart failure) and deaths.

Of the 106970 people who met the activity guidelines, 3.8% developed cardiovascular disease, compared to 5.1% of people who did not (23549 people). Risk of mortality was also higher for people who did not meet the recommended amount of activity – 6.4% compared to 4.2% for people who met guidelines.

The findings suggest that, if the entire population met physical activity guidelines, 8% of deaths (equivalent to around one in 12 cases) and 4.6% of cardiovascular disease cases (almost one in 20 cases) could be prevented. Furthermore, if the entire population was highly active (completing more than 750 minutes of physical activity a week), 13% of deaths (around one in 8 cases) and 9.5% of cardiovascular disease cases (around one in 10) could be prevented.

Overall, almost a fifth of people in the study (18%, 23631 people) did not meet the physical activity guidelines, but almost half (44%, 57868 people) were highly active.

Physical activity as transport, occupation or housework was the most common form of physical activity,  across all regions (ranging from 437 to 574 minutes per week). While physical activity in leisure time was common in high-income countries (average of 130 minutes per week), it was rare in other regions (25 minutes a week in lower-middle income countries and no time spent in this way in upper-middle- and low-income countries).

Overall, the more activity a person did the lower their risk of mortality and cardiovascular disease – with the study finding no ceiling effect on the association, and no risks associated with extremely high levels of physical activity (more than 2500 minutes per week, up to 17 times the physical activity guideline amount).

The authors recommend building physical activity into one’s daily lifestyle to achieve higher levels and reduce risk as much as possible.

“Our study found that high physical activity was only possible in people who completed physical activity as a form of transport, part of their job or through housework – with 37.9% people who acted in this way attaining this level of activity, compared to 2.9% who were only physically active in their leisure time. This reflects the challenge of trying to be highly active during limited daily leisure time outside of work and domestic duties,” says Dr Lear [2].

The authors note that the physical activity questionnaire used in their study may overestimate the amount of physical activity completed, meaning the benefits of exercise could be even higher than projected in the study.

Writing in a linked Comment, Dr Shifalika Goenka, Indian Institute of Public Health-Delhi (IIPH-D), Public Health Foundation of India (PHFI), and Centre for Chronic Disease Control (CCDC), India, says: “Cardiovascular disease is known to have devastating effects on individuals and families. In low-income and lower-middle-income countries, cardiovascular disease can push people to below the poverty line… Creating a physical, social, and political environment where physical activity in daily living is desirable, accessible, and safe should be a developmental imperative… Promotion of physical activity, active transport, and active living by means of interventions contextualised to culture and context will have powerful and long-lasting effects on population health and developmental sustainability.”

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Expert Reaction

These comments have been collated by the Science Media Centre to provide a variety of expert perspectives and reflect independent opinion on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.

Professor Jacqueline Phillips is Professor of Physiology from the Faculty of Medicine and Health Sciences, Macquarie University

Exercise is good for you, more exercise is better and it doesn’t matter how you get it - working, travelling or playing.

This study is pretty impressive - both in its size and scope, and the simplicity of its outcome, and the implications for our health has two sides. Firstly, for people who don’t have the luxury of the time or money for recreational exercise, physical activity through work activities or as a mode of transport can be of enormous protective benefit for preventing heart attack and stroke. And secondly, for those who exercise recreationally but have an otherwise sedentary lifestyle, you need to get out more and move – the higher levels of protection that exercise can give just can’t be achieved by being a weekend warrior.

We have known for some time that exercise is good for you but this study shows that this is a world wide phenomena, independent of where you live, your sex, age, body weight, if you smoke or have diabetes. And the benefits of exercise may not only reduce cardiovascular disease, but might also reduce the incidence of cancer and lung disease. And critically, exercise is so much easier and cheaper to implement than any other intervention currently available to us.

Last updated: 22 Sep 2017 11:44am
Professor Ken Nosaka is the Director of Exercise and Sports Science in the School of Medical and Health Sciences, Edith Cowan University

It has been well documented that a lack of physical activities is the main cause of mortality, and the study in the Lancet confirms this, thus it is nothing very new.

However, the study is admired for the large sample size; more than 130,000 participants from 17 different countries with different economic levels. 

The main findings of the study is that performing any kind of moderate or high physical activities reduces cardiovascular diseases and mortality, and higher physical activity lowers the risk of cardiovascular diseases and mortality even more so. 

Therefore, increasing physical activities are the key strategies to reduce deaths and cardiovascular diseases. The authors state that the results of the study provide robust evidence to support public health interventions to increase all forms of physical activity. 

So, one of the obvious questions is “how.”

I assume that most people already know the importance of physical activities for health and wellbeing, but not many people actually meet the recommended amount (e.g., 150 min of moderate exercise per week).  

Thus, it is important to know why people do not respond to these kinds of messages based on research, and why people remain physically less active.

We need to know more on how exactly we can increase physical activity.

Last updated: 21 Sep 2017 5:46pm
Associate Professor Robyn Woods is from the School of Public Health and Preventive Medicine, at Monash University

Important public health message that applies to not only high income countries but also moderate and low income countries where death from CVD is highest.

Findings from this large study of >130,000 people across many countries provide convincing evidence supporting the messages we all hear from cardiologists and medical practitioners that exercise is good for our health.

Modest regular exercise such as walking for 30min a day, five days a week, whether as recreational or lifestyle activity, significantly reduces risk of cardiovascular disease and death in everyone, regardless of income.

More physical activity than this affords further cardiovascular risk protection. 

Although the physical activity measures were self-reported and not measured independently, if the activity levels were over-reported, the relationship between activity and reduction in CVD and mortality risk would be even higher.   In a study of this magnitude, direct measures of physical activity would have been prohibitively expensive.

Last updated: 21 Sep 2017 4:47pm
Professor David Dunstan is Head of Physical Activity at the Baker Heart and Diabetes Institute

Approximately 60 per cent of the Australian adult population do not meet the minimum recommendation of >150 min/week of physical activity, and this has not changed in two decades. Rapid modifications to work, transportation and domestic environments over the past 2 decades has led to diminished opportunities for physical activity throughout the day - most Australian adults now spend more time sitting (~9 hrs) than they spend sleeping.
 
Movement (physical activity) is acknowledged as being the antidote to sitting – these findings clearly emphasise the importance of shifting the ever increasing number of people who do little or no physical activity to doing ‘some’ physical activity, since even low amounts of physical activity provides substantial benefit. 
 
The authors key message of ‘incorporating physical activity into a daily lifestyle whether through active transportation, occupation, or domestic duties has the potential to achieve higher physical activity and lower risk’ further reinforces current Australian public health efforts that promulgate the message of ‘Make your move – sit less – be active for life'. Additionally, as participating in physical activity is a low-cost approach to reducing deaths, this research further supports calls for a national physical activity plan to address the alarming rates of inactivity in the Australian population.

Last updated: 21 Sep 2017 4:24pm
Tim Olds is a professor in the School of Health Sciences at the University of South Australia.

This research supports a very substantial body of existing research showing that physical activity is cross-sectionally associated with reduced all-cause and cardiovascular mortality. We find similar associations in longitudinal and intervention studies.

This research extends previous findings in that it covers a large number of countries across a wide spectrum of Human Development Index values.

Grandma was right: exercise is good for you.

Last updated: 21 Sep 2017 4:20pm
Dr Brigid Lynch is a Senior Research Fellow with Cancer Council Victoria’s Cancer Epidemiology Centre

This study collected data on the physical activity of individuals in low, middle and high income countries, and re-affirms that physical activity is an important strategy for decreasing risk of cardiovascular disease and mortality. Importantly, the research shows that there are benefits associated with physical activity in a range of settings – at work, for transport – as well as exercise during leisure time (which has been the focus of most studies to date). Physical activity was beneficial for individuals regardless of whether they were young or old, overweight or not, smokers or not, or had a pre-existing chronic disease or not.

When interpreting the results of this study it’s important to understand that physical activity was self-reported using a questionnaire that tends to overestimate the total amount of activity per day. So, interpret the minutes per week reported with caution – it’s likely that health benefits are achieved with lower levels of physical activity than reported by this study. Another consideration is that physical activity was only measured once – we don’t know if people changed their activity levels afterwards.

The take-home message is that being physically active across the day, in a range of settings, has important health benefits for everyone.

Last updated: 21 Sep 2017 4:19pm
Professor Kevin Norton is from The School of Health Sciences at The University of South Australia

This large international study took place across a range of countries from low to high income levels. It also ran for almost a decade. A simple questionnaire asked about 140,000 adults to list typical weekly physical activity (PA) patterns (occupation, transport, household and recreational types) and the responses were used to categorise people according to the amount of total PA undertaken per week. 

Over the next four years these volunteers were tracked to see who developed cardiovascular disease or had a stroke and who died of heart disease. As has been found in many other studies of a similar nature, the results showed a graded or increasing level of benefit (protecting against heart disease) with increasing levels of total PA across all income levels. Using special statistics the study was able to show how many people would potentially be saved from having a heart attack or dying each year if more people undertook regular PA of at least 150 min/week of moderate intensity. The study also showed the health benefit increased if people did higher levels of PA.

Finally, it was calculated that about one in 12 deaths globally could be prevented with half an hour of PA, five days a week and that one in 20 cases of heart disease could be prevented with this level of exercise. This study supports several other large surveys of a similar nature. They invariably point to the same phenomenon: regular PA can reduce the probability of developing heart disease or stroke, or dying of a heart attack.

Last updated: 21 Sep 2017 4:14pm
Emeritus Professor Mark Wahlqvist is former Professor and Head of Medicine at Prince Henry’s Hospital and Monash Medical Centre, Associate Dean (International Health and Development) and Director of the Asia Pacific Health and Nutrition Centre

The evidence that modest amounts of regular physical activity improves general health, reduces disability and prolongs life is now clear. The PURE exercise study of 130,000 people for 7 years on average adds to this evidence, especially for a wide range of socio-economic and cultural settings.  It considers both recreational and non-recreational exercise and focusses on all-cause mortality and cardiovascular events. 

Sight should not be lost of an even larger and more comprehensive outcome study* of some 416 175 individuals, men and women, followed for 8 years on average in Taiwan, where a dose-response reduction from as little as 15 minutes per day, not only in all-cause and cardiovascular, but also cancer and diabetes mortalities was seen. The Taiwanese study was published in 2011, also in the Lancet, but not referenced by the PURE exercise study authors. Both studies show that, irrespective of cardiovascular risk factors or comorbidities like being overweight or having hypertension or diabetes, the benefit is seen. 

As pointed out in an accompanying commentary by Goenka and Lee (3), the contextualisation of exercise and health is crucial. The benefits of exercise may accrue through engagement with public open space and with others. The findings may represent a deeper understanding of movement and health as socio-ecological."

*Chi Pang Wen, et al  'Minimum amount of physical activity for reduced mortality and extended life expectancy: a prospective cohort study.'  The Lancet August 16, 2011 http://dx.doi.org/10.1016/S0140-6736(11)60749-6

Last updated: 21 Sep 2017 4:11pm

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