As many as six million middle-aged adults in England are putting their health at risk by failing to manage even a brisk ten minute walk each month, according to research.
A report by Public Health England (PHE) says that a quarter of the English population is "inactive" - doing less than 30 minutes of activity per week.
Four out of ten adults aged 40 to 60 - 6.3 million people - were found to walk less than ten minutes continuously at a brisk pace once a month.
To tackle the high levels of inactivity, the health body is urging people to build 10 minutes continuous brisk walking into their day, which experts say should be at a speed of at least 3mph.
To help people achieve this goal, PHE has created a new app - Active 10 - which GPs are recommending to their patients.
Dr Jenny Harries, deputy medical director at PHE, said: "I know first hand that juggling the priorities of everyday life often means exercise takes a back seat.
"Walking to the shops instead of driving or going for a brisk 10-minute walk on your lunch break each day can add many healthy years to your life.
"The Active 10 app is a free and easy way to help anyone build more brisk walking into their daily routine."
As well as increased fitness the health benefits of walking for ten minutes each day include a 15% reduction in the risk of dying prematurely, PHE said.
In 2011 health chiefs said people should be carrying out at least two and a half hours of moderate intensity activity every week.
Though the new report found that some people may find 150 minutes of exercise "unrealistic".
Professor Sir Muir Gray, clinical adviser for the Active 10 app and the One You campaign, added: "We all know physical activity is good for your health, but for the first time we're seeing the effects that easily achievable changes can make.
"By walking just 10 continuous minutes at a brisk pace every day, an individual can reduce their risk of early death by 15%.
"They can also prevent or delay the onset of disability and further reduce their risk of serious health conditions, such as type 2 diabetes, heart disease, dementia and some cancers."