In a study published in npj Digital Medicine, the researchers found that while activity levels then slowly declined over time, even after 30 months those users who were still using the app were more active than they had been beforehand.
Lack of physical activity is linked to poor health, including higher rates of heart disease and stroke, type 2 diabetes, cancers, dementia, depression and early death. Almost 4 million premature deaths per year - and healthcare costs of US$27 billion - are attributable to physical inactivity.
In England, more than one in three (37%) adults do not reach the recommended 150 minutes per week of moderate-intensity activity - which can include brisk walking - and around one in four (26%) adults does less than 30 minutes per week.
Recently, mobile health apps have grown in popularity, allowing users to track their physical activity, offering tailored feedback, goal setting opportunities and activity reminders throughout the day. One such app is NHS Active 10, launched in 2017 to increase brisk walking levels, as walking is the most common form of activity reported by English adults. The app has been downloaded over 1.5 million times since its introduction.
In the first formal evaluation of its effectiveness, researchers from the University of Cambridge examined anonymised data from more than 200,000 users of the app - those who used the app for at least a month - collected between July 2021 and January 2024. These users had agreed for their anonymised data to be collected and shared for research purposes.
Three quarters of those users who provided demographic information were women, and the average age of users was 51 years. One in three users (32%) was aged 60 years or over.
Following download, the app requested permission from users to access their historical walking data. This revealed that prior to using the app, individuals spent on average 12.3 minutes per day in brisk walking and 30.4 minutes per day in non-brisk walking.
On the first day the app was downloaded, users walked on average an additional 9.0 minutes per day briskly. Their non-brisk walking increased by 2.6 minutes per day.
Over time, the amount of brisk walking done by users declined, falling on average 0.15 minutes per day for each month that passed. The amount of non-brisk walking also fell, by 0.06 minutes per day for each month that passed.
Over a third of users (35%) were still using the app after six months and a fifth (21%) after a year. This is much higher than the average for health and fitness apps worldwide, where typically less than three in 100 users (2.8%) are still using the app after 30 days.
At the end of 30 months, users were still walking an average of 4.5 minutes more per day briskly and 0.8 minutes per day more non-briskly than before they began using the app.
First author Dr Dharani Yerrakalva, from the Department of Public Health and Primary Care at the University of Cambridge, said: "Even though activity levels fell over time, people still using the app after more than two years were doing more physical activity than before they started using it.
"At the population level, other research has suggested that we would see significant health benefits from even modest increases in activity such as this. Previous work by colleagues at Cambridge suggests that just 11 minutes a day of brisk walking could prevent one in 10 premature deaths."
Senior author Professor Simon Griffin, from the Department of Public Health and Primary Care and the Medical Research Council Epidemiology Unit at the University of Cambridge, said: "Active 10 appears to have a been a success, in that it encouraged 200,000 people to increase their levels of moderate physical activity. We should now consider whether apps such as this can be integrated into NHS practice, for example providing data to GPs so they can monitor their patients’ progress and provide tailored advice, to help us move towards a more personalised approach to medicine."
The research was funded by the National Institute for Health and Care Research (NIHR) and Medical Research Council, with support from the NIHR Cambridge Biomedical Research Centre.
"It's right there in my face if I've been lazy!" - Sonali Shukla
Sonali Shukla is a careers consultant at the University of Cambridge. Living in Cambridge, she was used to cycling to work, but when her daughter was born, she found that a combination of looking after her and the recent Covid lockdowns meant she had become less active.
"I started using the NHS Active 10 app around six months after my daughter was born," she says. "I was looking for ways to get a bit more active. I was intrigued because I've used the step counter on my phone, but what was interesting about this one is that it tracks your brisk walking."
Sonali initially downloaded the app out of curiosity so see whether or not she walked briskly, but then found herself hooked, motivated by the trophies and celebrations it gave when she completed 10 minutes of brisk walking.
She found the results illuminating as it highlighted the impact her daughter had on her physical activity levels, even when she thought she was getting enough exercise. "I might go for an hour long walk, but when I've got small children in tow, it's too leisurely to really count as proper exercise."
Even now, three years later, she still uses the app. "The version that I have on my phone has a little tracker that you don't have to log into the app to see. It tracks your brisk walking on the face of your phone. So it's right there in my face if I've been lazy!"
Sonali has managed to keep active, and although the app isn’t the only reason why, she says it certainly helps.
"When the weather's bad and it's not as easy to just go for a walk, I might notice that it's been a couple of days before I've really moved. It encourages me to go outside and get moving."
Yerrakalva D, Hajna S, Brage S, Griffin SJ.
Evaluation of the NHS active 10 walking app intervention through time-series analysis in 201,688 individuals.
NPJ Digit Med. 2025 Aug 6;8(1):441. doi: 10.1038/s41746-025-01785-x