select search filters
briefings
roundups & rapid reactions
Fiona fox's blog
A study published in The Lancet looks at small changes in physical activity and mortality risk.
Dr Richard Godfrey, Senior Lecturer in Coaching and Performance, College of Health, Medicine and Life Sciences, Brunel University of London, said:
“This is an excellent study with important findings, based as it is, on such a large number of individuals used. That the large number of individuals increases the statistical significance of the findings should see health care workers, policy makers etc take notice of them.
“Behaviour change is the most challenging aspect of getting people to be more active. It is entirely realistic to find time for increasing physical activity but less so if we are expecting people who currently do little or nothing to be self-motivated to change. Low self-motivation or discipline is generally part of those who do in sufficient volume and intensity of PA such as the obese. However, it is very important to acknowledge that simply suggesting more PA risks oversimplifying what are often complex issues underlying specific conditions. Proper individual assessment and customised exercise programme may therefore be best.
“I would say that moderate physical activity is consistent with eliciting a heart which is 60-80% of the individual’s maximum heart rate (HRM), vigorous is 80-100% of the individual’s HRM. For people who are very inactive it may be sufficient to estimate HRM as 220-age.
“The study would to me, reinforce how important any increase in PA is BUT also implies the great requirement to also avoid decreases in PA. There may be an argument that a 5 min decrease per day in physical activity is problematic and so GPs, policy makers etc should ensure we prioritise being mobile enough to engage as fully as possible with PA guidelines. So, any minor issue, a damaged toe for example, that reduces ability to be active should be considered very seriously to ensure people are able to meet guidelines or even to avoid very small decreases in PA.
Dr Daniel Bailey, Reader – Sedentary Behaviour and Health, College of Health, Medicine and Life Sciences, Brunel University of London, said:
“This study shows that even with small increases in MVPA, or reducing sitting time by 30 minutes per day, this could help prevent some deaths. If people can do more than 5 or 10 minutes a day, then we would expect even more deaths could be prevented. The 150 minutes of moderate-to-vigorous physical activity per week is still a goal that people should aim for, if possible, as this will help them get the most health benefits.
“The really promising finding from this study is that just an extra 5 minutes per day of MVPA can help. This should be feasible for most people, even those who only do very small amounts of physical activity already.
“Moderate activities are those what make us breathe a bit heavier and feel warmer. So simple daily activities like a brisk walk, housework or gardening will do the trick. And if we want to reduce sitting by 30 minutes a day, this can be swapped for light activities like pottering around the house or a slow walk.
“A clear message we want to get across if that every movement counts and getting inactive people to doing some activity is where we see the biggest gains in health. So, GPs, policymakers, or campaigners can certainly be looking to support patients and the public with making these relatively small changes to start with, which would give people a starting point to then kick on and increase their activity even more.
“We should certainly be telling the public that every minute counts. The risk comes if everyone think they only need to do 5 minutes of MVPA per day and that’s it. If people are still spending long periods of the day sitting down and not moving about, we know this will increase their risk of disease and early death. Even more deaths are likely to be prevented if we can reach higher amounts of MVPA and limiting the amount of time we spend sitting.”
Prof Aiden Doherty, Professor of Biomedical Informatics, Nuffield Department of Population Health, University of Oxford, said:
“Yes”
“This is an excellent analysis carried out by an internationally renowned scientists, using the best available data sources that are a leap forward from the information that we have had available in the past.”
“While this might seem like yet another ‘more physical activity is good for you’ study, the authors have added important new details. Healthcare systems are under enormous strain. This paper indicates that up to 10% of all premature deaths might be prevented if everyone were to make small and realistic increases to their moderate-intensity physical activity of 5 min/day. Reducing sedentary time by 30 min/day would likely result in a smaller, but still meaningful, number of averted deaths.”
“As well as can be done for a study of this type. As noted by the authors this research is limited to data that is only from high-income countries.”
“For now, I still urge adults to follow the WHO Physical Activity Guidelines and aim to engage in at least 150 minutes of moderate-intensity physical activity a week. This can also be 75 minutes of vigorous-intensity or an equivalent combination of moderate- and vigorous-intensity physical activity. In addition, adults need at least 2 days of muscle-strengthening activity each week. However, the results from this new study show that every move counts!”
“Unfortunately, it is impossible to conduct a large-scale randomised controlled trial of physical activity to investigate its effect on long-term health outcomes. It is therefore not possible to definitely make causal claims from this paper. However, the authors have conducted a very careful analysis on a very important topic.”
Prof Amanda Daley, Professor of Behavioural Medicine, Loughborough University, said:
“We all know that physical activity is good for our health, yet many people struggle to do it regularly. Consistent with previous research studies, this large international observational study has shown that even small bouts of physical activity may be associated with decreasing the number of people who die every year.
“This study further highlights the importance of recognising that even a few minutes of physical activity each day can impact the health of the population, and that some physical activity will always be better than doing nothing at all. This is an important health message that we need to convey to the public.”
Prof Kevin McConway, Emeritus Professor of Applied Statistics, Open University, said:
“This is an interesting study, but it needs careful interpretation and has some important limitations.
“Put too simply, the overall conclusion is that there are differences in death rates (for total deaths from all causes) between groups of people aged 40 and over who have different levels of physical activity. Generally, the more the physical activity, and the less time people were sedentary, the lower was their death rate on average.
“Really that doesn’t sound terribly surprising, given what has been found about levels of physical activity and health in previous research. But there are reasons why this study is going further than many previous studies. These are what (in my view) make the research worthwhile.
“The participants’ physical activity levels were measured with accelerometers that they wore on their bodies (hip or wrist). That could lead to a more objective measure of how much physical activity they performed, compared to many previous studies which measured activity from what participants reported they had done.
“Also, importantly, the statistical methods that the researchers used allowed them to estimate differences in death rates for participants whose physical activity amounts varied by fairly small amounts – 5 or 10 minutes of moderate to vigorous intensity physical activity (MVPA), or 30 or 60 minutes of sedentary time. Because of this, the new study can report on the possible benefit of rather small changes in the amount of exercise people do or the amount of time they spend sitting or lying down. Many previous studies could not do that.
“So what do we have to be careful about in interpreting the results? There are issues about what is causing what, and there are reasons why we really can’t be too sure about exactly what differences in numbers of deaths are associated with the changes in activity levels that the researchers looked at.
“This is an observational study, so the differences in death rates between different groups of participants could, in part or even wholly, be caused by differences in other factors rather than differences in their physical activity levels. This is (rightly) stated in the research paper and the press release. The researchers did make statistical adjustments to try to allow for many differences between the groups, such as differences in age, height, weight, smoking habits, whether they had had some chronic diseases, and more. But one can never be sure that everything relevant has been adjusted for, so some doubt about cause and effect remains.
“Then, the research paper and the press release talk about changes in death rates if people changed their activity levels. But the researchers did not directly look at changes in activity levels or death rates in individuals. They only measured each person’s physical activity over one relatively short period of a few days. What they are in fact doing is comparing the death rates in separate subsets of the participants, whose activity levels differ by certain amounts.
“When they say (for instance) that a 5 minute per day increase in MVPA (moderate or vigorous intensity physical activity) in the least active participants would lead to an estimated reduction of 6% in the number of deaths, this isn’t based on looking at differences between individuals who started doing an extra 5 minutes exercise and others who didn’t change. It’s estimating how the numbers of deaths in 8 years in the existing population would compare with a hypothetical population where the least active participants were doing another 5 minutes a day. That might be close to what we’d see if the population’s activity level changed in that way – but it might not be.
“There’s something that confused me in the press release at first, which I’ll mention in order to make it clearer what the research is actually estimating. The release says in its first paragraph, “Moderate-intensity physical activity […] for an extra five minutes a day is associated with a 10% reduction in all deaths in the majority of adults […] and around 6% of all deaths in the least active adults […]”. There are similarly worded statements about other comparisons elsewhere in the release.
“It sounded a bit odd to me that there was a smaller percentage change, associated with the same 5 minute a day change in activity, in death rates in the fifth pf the population that were least active, than in the group of four fifths of the population that were already doing more exercise on average. It’s possible that in fact things are like that – maybe a change of 5 minutes just isn’t enough to affect the least active people so much.
“But in fact that’s not what the researchers are saying, as the research paper makes a bit clearer (in the text on the page below Figure 1, and elsewhere).
“The estimated 6% difference between the actual deaths and the estimated deaths if the least active fifth of the participants did an extra 5 minutes of MVPA per day (but the rest of the population didn’t change their activity) is a percentage difference in total deaths in the whole population. Quite a substantial change, since under this scenario their assumption is that four fifths of the population would not change their activity levels.
“The estimated 10% difference between the actual deaths and the estimated deaths if all but the most active fifth of the participants did an extra 5 minutes of MVPA per day (but the most active fifth didn’t change their activity) is again the percentage difference in total deaths in the whole population. We know (roughly, anyway) from the previous paragraph that the reduction in total deaths from just the least active fifth doing 5 minutes more exercise is 6% of the total – so about a 4% reduction corresponds to everyone between the lowest fifth and the highest fifth doing an extra 5 minutes MVPA a day.
“This all makes more sense – increasing physical activity is most important in those who currently do least. It also fits with the statistical model that the researchers used to make their estimates of differences.
“The same goes for the other figures in the press release. When they talk about percentage changes or differences in numbers of deaths, they mean a change in the total deaths (from all causes) in the whole population, over the follow-up period, not just in the groups who are assumed to change their physical activity.
“It probably ought to go without saying that, when the researchers refer to a ‘reduction in deaths’, they are talking about deaths during the average 8-year follow-up period, during which time about 6 in every 100 participants died (so that about 94 in every hundred had not yet died – in the long run we’re all dead, I’m afraid). OK, I’m nit-picking, but people do get concerned about this point sometimes.
“Having described what the researchers are actually estimating, I’ll turn to a point that the researchers mention, which I think is important and which means that actually it’s very difficult to be sure of what the reductions in deaths during follow-up would be, in percentage terms.
“The participants in the research fall into two groups, according to the researchers. About 40,000 of the were in seven separate studies carried out in Scandinavia and the USA within a collaboration called the Adult Accelerometer Consortium. They used similar methodologies to one another, and for instance used similar sorts of accelerometer worn on similar parts of the body (hips). The biggest group of participants, about 95,000 of them, came from the UK Biobank study. That used accelerometers worn on the wrist rather than the hip, used different algorithms to estimate the times performing different levels of activity from the other studies, and there were other differences too.
“The figures I specifically quoted above on differences that might occur in deaths during follow-up, if some people did more exercise, are from the Consortium studies alone. All the figures in the press release for the percentage reductions in deaths are also from the Consortium data alone, even though 7 in every 10 participants were from UK Biobank.
“But the researchers also made separate estimates of the differences that might occur in deaths during follow-up, from the UK Biobank data.
“The UK Biobank data led to estimated reductions in deaths following roughly the same pattern as in the Consortium data, but the reductions were smaller.
“For example, based on the Consortium studies, the researchers estimated that there would be about 6% fewer deaths across the whole population if the people in the lowest fifth of physical activity all did an extra 5 minutes per day of MVPA. Based on the separate UK Biobank data, the estimate is that the reduction (making the same comparison) would be about 2% rather than 6%.
“There are other comparisons between the two groups of studies in Table 3 in the research paper. The estimated differences in deaths during follow-up are all smaller for the UK Biobank data than for the Consortium data – sometimes rather a lot smaller, sometimes less so.
“There are all kinds of possible reasons for these differences. Perhaps it’s due to using different accelerometers, placed differently on the body. Perhaps it’s because of different ways of estimating the daily time carrying out different levels of activity from the accelerometer recordings.
“Perhaps it’s because the people in the UK Biobank cohort are in some way different from those in the other cohorts. The researchers mention that the UK Biobank participants were not specifically chosen to represent the UK population as a whole, and it’s known that they are on average healthier than the overall population. They point out that five of the seven studies from the Consortium were chosen to be representative of the population in the places where they were carried out. But in fact the two that were not chosen to be representative of their population are the biggest two of the Consortium studies in terms of numbers of participants, and together account for about 23,500 of the 40,000 Consortium study participants.
“I think what we can take from this is that the research provides evidence that rather small differences in activity levels can correspond to potentially very worthwhile differences, at population level, in the risk of early death. But the different detailed findings from the UK Biobank and Consortium results show that one really can’t be sure how big the differences in early death rates actually are.
“Also, however plausible it looks that even small changes in activity might lead to worthwhile improvements at whole-population level, one mustn’t forget that this is all observational data and there are inevitable doubts about exactly what causes what.
“The researchers are aware of all that, which is why they are rather tentative in their conclusions, and call for more research – including similar research in low and middle income countries where many aspects are different.
“Incidentally, there’s a good reason why the researchers made two sets of estimates for differences in activity, first for only the least active fifth of people (which they call the ‘high-risk approach’ since they are considering what would happen advice and encouragement to change activity were concentrated on the people at highest risk of early death), and also for differences in activity for everyone except the fifth who are most active (which they call the ‘population-based approach’, because it might occur if a big majority of the population was encouraged to be more active). Since we can’t force people to be more active, but can only use persuasion, it’s useful to compare the effect of possible different approaches to, and results of, persuasion.”
Dr Brendon Stubbs, Senior Researcher & Physiotherapist Kings College London, King’s College London (KCL), said:
“This well-conducted individual participant data meta-analysis uses device-measured activity data to show an association between increases in moderate-to-vigorous exercise of just 5 minutes daily could avert 6% of deaths in the least active groups or 10% population-wide, while trimming sedentary time by 30 minutes might prevent 3-7%.
“This finding offers hope, especially to the least active, serving as an inspiring public health message; even small daily tweaks to activity levels can make a meaningful difference, for instance a quick brisk walk, climbing a few extra flights of stairs, or playing energetically with the (grand)kids.
“Ultimately this is an observational study, it cannot prove causation, randomised controlled trials would be ideal to confirm if these changes directly reduce deaths. However multi-decade RCTs on physical activity to prove causation for outcomes like death are notoriously challenging/impractical due to time, expense, adherence issues, and the difficulty of blinding participants to their own activity levels. “
‘Deaths potentially averted by small changes in physical activity and sedentary time: an individual participant data meta-analysis of prospective cohort studies’ by Ulf Ekelund et al. was published in The Lancet at 23:30 UK time on Tuesday the 13th of January 2026.
Declared interests:
Dr Richard Godfrey: “none”
Dr Daniel Bailey: “none”
Prof Aiden Doherty: “AD’s research team at Oxford is supported by a range of grants from the Wellcome Trust [223100/Z/21/Z, 227093/Z/23/Z], Swiss Re, GSK, Boehringer Ingelheim, Google, National Institutes of Health’s Oxford Cambridge Scholars Program, EPSRC Centre for Doctoral Training in Health Data Science (EP/S02428X/1), British Heart Foundation Centre of Research Excellence (grant number RE/18/3/34214), Cancer Research UK, and funding administered by the Danish National Research Foundation in support of the Pioneer Centre for SMARTbiomed.“
Prof Amanda Daley: “I receive research funding from NIHR/DHSC to conduct research related to how to support the public to make small changes to their lifestyle behaviours. I have no other conflicts of interest to declare.”
Prof Kevin McConway: “I have no conflicts of interest to declare.”
Dr Brendon Stubbs: “Editorial Board of the Journal of Physical Activity and Health, Ageing Research Reviews, Mental Health and Physical Activity, The Journal of Evidence Based Medicine, and The Brazilian Journal of Psychiatry. Brendon has received honorarium from a co-edited book on exercise and mental illness (Elsevier), an associated education course and unrelated advisory work from ASICS and FitXR LTD.”