In recent years, the 10,000-steps-a-day regime has become entrenched in popular culture. You can barely walk down the street without someone stomping past you wearing a FitBit; when Jeremy Hunt was health secretary, he was often pictured with his poking out from his shirtsleeves. It has become a global obsession: the research firm Gartner recently estimated that by 2020 there will be 500m wearables adorning consumers across the world.

This is all despite the fact that 10,000 steps is a completely arbitrary figure, one that originates from a successful Japanese marketing campaign in the mid-60s. In an attempt to capitalise on the immense popularity of the 1964 Tokyo Olympics, the company Yamasa designed the world’s first wearable step-counter, a device called a manpo-kei, which translates as “10,000-step meter”.

“There wasn’t really any evidence for it at the time,” says Prof David Bassett, head of kinesiology, recreation and sport studies at the University of Tennessee. “They just felt that was a number that was indicative of an active lifestyle and should be healthy.”

A research team at Kyushu University of Health and Welfare began to investigate the potential benefits of taking 10,000 steps. They concluded that the average Japanese person took between 3,500 and 5,000 steps a day, and that if these people increased their daily step count to 10,000, they could decrease their risk of coronary artery disease.

But while the World Health Organization, the American Heart Foundation and the US Department of Health & Human Services have all gradually adopted 10,000 steps as a daily activity recommendation, in recent years the veracity of this number has been increasingly called into question. Earlier this year, Mike Brannan, national lead for physical activity at Public Health England declared: “There’s no health guidance that exists to back it.”

Indeed, most of the scientific studies that have been conducted to try to test whether 10,000 steps a day is optimal for health are themselves relatively arbitrary. They simply compare people who have done 10,000 steps a day with those who have done far lower numbers, such as 3,000 or 5,000, and then measure calories burned, blood pressure and blood glucose levels.

“This number keeps being reinforced because of the way research studies are designed,” says Prof Catrine Tudor-Locke of the Center for Personalized Health Monitoring at the University of Massachusetts Amherst. “So, the study might find that 10,000 helps you lose more weight than 5,000 and then the media see it and report: ‘Yes, you should go with 10,000 steps,’ but that could be because the study has only tested two numbers. It didn’t test 8,000, for example, and it didn’t test 12,000.”

For those who are chronically ill, have type 2 diabetes, or older individuals who are used to a more sedentary lifestyle, there are now concerns that making a rapid jump to 10,000 steps a day could have adverse consequences. For others, the milestone may seem intimidating and can derail intentions to increase daily physical activity.

“We know that sedentary lifestyles are bad, and if you’re taking fewer than 5,000 steps a day on average this can lead to weight gain, increase your risk of bone loss, muscle atrophy, becoming diabetic and this litany of issues,” Tudor-Locke says. “But, at the same time, there seems to be an obsession about 10,000 and how many steps are enough, yet it’s more important, from a public health point of view, to get people off their couches. The question we should really be asking is: how many steps are too few?”

Some studies investigating the protective nature of exercise against chronic illnesses ranging from heart disease to stroke and various forms of cancer, such as breast cancer and reproductive cancers, suggest that somewhere between 6,000 and 8,000 steps could be the lower boundary to aim for.

“Six thousand steps and above is getting you into that range of what these studies are showing and is protective against cardiovascular disease, in particular,” Bassett says. “And for people who have elevated risk factors to begin with, this can cause an improvement in those risk factors.”

Scientists who have attempted to calculate an exact number of steps that equate to the public health guidelines of 30 minutes of moderate exercise per day, have found that we should perhaps aim for a minimum of 7,500 steps.

But while the rise of the step-counter industry has led to a generation of fitness lovers fixated on achieving 10,000 steps, there is also currently no known upper ceiling on how much is good for us. Exercise scientists are currently trying to conduct studies to see whether 15,000 or even 18,000 steps have long-term health benefits over the traditional 10,000 benchmark.

Scientists who have studied the Amish people in rural Canada, who use no motorised forms of transport, have found that they average 14,000-18,000 steps a day, while a study of Japanese patients with type 2 diabetes from the mid-90s found that those who averaged about 19,000 steps a day had far better outcomes compared with those who remained largely sedentary.

One of the major problems with the 10,000-steps-a-day goal is that it doesn’t take into account the intensity of exercise. Getting out of breath and increasing your heart rate may well be even more important than the exact number of steps taken. Researchers are currently conducting studies to see whether people who take 10,000 steps a day merely by pottering around their house achieve the same health benefits as those who do so by brisk walking or playing sport.

“More recently, scientists have started looking at cadence, which is the idea of step rate or frequency of stepping,” Tudor-Locke says. “When intensity’s better, your heart is pounding a little faster, more blood goes through your body, things are crossing the cell wall that need to; all these things are happening quicker.”

In June, Tudor-Locke published some of the first findings on this, in a paper titled How fast is fast enough? It suggested that a minimum of 100 steps per minute is required for exercise to be beneficial. “This is the kind of pace which you naturally ascend to when you’re doing purposeful walking,” she says. “But this is just the beginning of this area of research: looking at how healthy people are not just by how many steps they’ve taken, but the rate at which they’ve done it.”