Last Christmas someone kindly bought me a Fitbit. For the uninitiated, it is a fitness tracker you wear on your wrist. It counts your steps, distance travelled and heart rate and uses those things to calculate how many calories you’ve burned. The device can even track how long you sleep.

For a couple of weeks I used it every day, monitoring my daily activity and making sure I reached the magic 10,000 daily steps recommended by the Government for optimum health. Then, some time around mid-January, it went into a drawer where it has remained ever since.

Why? Well, it was partly because I found constantly trying to hit the 10,000 steps a day target so hard to achieve.

But it was also because I discovered that the 10,000 steps figure is not based on rigorous scientific studies. In fact, it was the result of a 1960s marketing campaign in Japan. In the run-up to the 1964 Tokyo Olympics, a Japanese firm came up with a pedometer called a Manpo-Kei. In Japanese, ‘man’ means 10,000, ‘po’ means steps and ‘kei’ means meter. So it was, literally, a 10,000 steps meter. It was then heavily advertised to health-conscious Japanese.

It obviously made a big impression. But do you really have to do 10,000 steps to improve your physical and mental fitness?

To find out, I got together with Professor Rob Copeland, from Sheffield Hallam University, to conduct an experiment in which we would compare the benefits of doing 10,000 steps against a plan called Active 10.

With Active 10, you don’t need to count steps. You simply aim to do three brisk ten-minute walks a day. This adds up to about 3,000 steps, or around 1½ miles – clearly a much shorter distance.

First we recruited a small group of sedentary middle-aged volunteers and equipped them with fitness trackers.

Rob then split them into two groups: one was asked to hit the 10,000-step target while the other was asked to do Active 10. The latter group were asked to keep their pace up so they would be working the heart and lungs. As Prof Copeland told them: ‘You are aiming to walk fast enough so that you can still talk but not sing.’

A few days later, we met up with our volunteers again and looked at their activity monitors. It turned out that those who had been asked to do 10,000 steps had mostly managed to hit their target but they had struggled.

The Active 10 group, on the other hand, had found it relatively easy to squeeze three brisk walks into a busy day.

So reaching 10,000 steps daily was harder to do – but was it any better for health? Prof Copeland thinks not. ‘According to the trackers, the Active 10 group were more often walking briskly enough that it counted as moderate to vigorous physical activity, even though they moved for less time. And it’s when you are doing a moderate-intensity activity that you are starting to get the greatest health benefits.’

It other words, although the Active 10 group did much less walking, they got more out of it.

SO doing a few short brisk walks a day is good for your physical fitness, but what about your brain? Plenty of studies have shown that prolonged exercise will keep your brain young, but can a few short walks make any difference?

To find out, researchers from the University of California recruited 36 volunteers and asked them to either sit still for ten minutes or to pedal gently for the same amount of time.

They were then asked to do a memory test, where they were shown images of things such as trees and asked to press a button when they saw an image that was the same as an earlier one.

Surprisingly, volunteers did much better on this test after ten minutes of gentle cycling than they did when they had just sat around doing nothing.

Even more surprising, when the researchers repeated the experiment, but this time with the volunteers doing the memory test inside a brain scanner, they found that ten minutes of exercise had led to visible changes in their brains.

There were striking improvements in the connections between the hippocampus, which is the area of the brain associated with memory, and those areas linked with learning.

So what is going on? Nobody knows for sure, but Professor Michael Yassa, who led the research, believes this shows that even ten minutes of gentle exercise may enhance blood flow to the brain and cause healthy chemical changes.

He also thinks these findings are important for middle-aged people, as the hippocampus is one of the first areas of the brain to deteriorate as we age.

‘We are not talking about marathons,’ says Prof Yassa. ‘It looks as if people can improve their memory with a short walk or an easy session of something like yoga.’

So although when it’s cold and wet you may not fancy exercising, you owe it to your brain to get a little more active.

If you’d like some help, you can download a free Public Health England activity tracker app.