Are those fashionable fitness trackers arip-off?

By Sarah Rainey They claim to monitor heart rate, calories – and how many steps you take a day. But . . .

wHETHER you’re a gym-honed fitness fanatic or a couch potato getting in shape for summer, chances are you’ve come across a sports tracker.

If you don’t have one of these colourful bands strapped to your wrist, you’re well behind the curve.

Activity trackers — the most iconic of which is the Fitbit — are worn by 100 million people worldwide and the global industry is worth £1.9 billion.

The devices — wearable computers with elasticated straps and a watch-like digital screen — monitor a user’s movement throughout the day, tracking data such as distance walked or run, calories burnt and heart rate. They range in price from £30 to more than £500 and A-list fans include Gwyneth Paltrow, Barack Obama and Vogue editor-in-chief Anna Wintour.

They are best-known for encouraging wearers to achieve the ‘10,000- step goal’, a daily target that has become synonymous with keeping fit. Ten thousand steps a day (the equivalent of about five miles for someone with an average stride) is, manufacturers insist, all the exercise you need.

But that’s not the whole truth. In fact, it is perpetuating a decadesold myth that is leaving us all dangerously out of shape.

This week, health chiefs warned that one middle-aged adult in three in England is still physically inactive, and urged people to choose a brisk ten-minute walk (just 1,000 steps) rather than the 10,000-step target.

By relying on electronic devices to track our fitness goals, they said, we have become complacent about taking exercise.

So do fitness gizmos do more harm than good? Are they as accurate as they claim? And is 10,000 steps a con? We reveal the worrying secrets of your sports tracker...

10,000 STEPS IS AN OUT-OF-DATE PLOY

IT mAy sound like a nice round number, but 10,000 steps really doesn’t mean much. The figure is not the result of rigorous scientific research, but of a single study carried out five decades ago on a group of Japanese men.

In the run-up to the 1964 Tokyo Olympics, a company came up with a device to encourage people to be more health- conscious. It was called a ‘manpo-Kei’ — in Japanese, ‘man’ means 10,000, ‘po’ means steps and ‘ kei’ means meter or measure.

The device, an early pedometer, was based on the work of Dr yoshiro Hatano, an academic determined to increase people’s daily step count from 4,000 to 10,000, enabling them to burn an extra 500 calories a day.

He trialled the manpo-Kei at men’s walking clubs, where it was successful, not just among the men but among their fitness-conscious wives. yet the diet and exercise habits of an average person in 2018 are vastly different from those in Sixties Japan.

Not only do we eat more calories — particularly more animal fat — and walk a lot less (cars were comparatively scarce back then), but the height and body mass of the average Westerner is well above that of a Japanese person in that era.

‘It’s a neat way of measuring your movement in a day, but it should be a loose guideline, not a hardandfast goal,’ explains Jim Pate, senior physiologist at the Centre for Health and Human Performance, on Harley Street.

‘It varies between genders: the average stride for a man is one metre, so he is expected to cover 10km in a day, while women are walking shorter distances.’

So measuring distance might be a more accurate benchmark.

A TRACKER ON YOUR CHEST IS BEST

ALTHOuGH most trackers are designed to be worn on the wrist, there is evidence they are more effective on different parts of your body, such as the chest or ankle.

Trackers worn on the wrist use optical technology to ‘ see’ the blood pulsing through your veins. This involves shining green and red lights at your skin and testing how much of each colour it detects: blood reflects red light and absorbs green, so as your heart beats it will ‘see’ a pulse of red light whooshing past.

This may sounds clever, but there have been concerns about its accuracy and experts say trackers may only be truly effective if they are worn on a chest strap directly over the heart.

Indeed, in 2016, Fitbit owners from several u.S. states launched a lawsuit claiming the device’s heart rate monitors were inaccurate and could damage users’ health. The company disputed the claim and the lawsuit never went to court.

‘If you wear one on your wrist while running, the signal can drop in and out as your arm is moving around,’ physiologist Jim explains.

Confusingly, though, some trackers have a mode that allows them to be worn on the ankle — said to be more accurate when cycling or running.

HOW FRECKLES GET IN THE WAY

muCH like smartphones, trackers can fail in extreme temperatures.

users have reported problems in hot countries, with the sweat on their wrists disrupting heart rate readings and sometimes causing them to stop.

Others say that hair on their arms, freckles and tattoos routinely interrupt the signal.

Stormy weather can lead to inaccurate readings on the number of floors climbed in a day. This is because sports trackers detect elevation by measuring a change in air pressure (using a device called an altimeter). Wind or passing weather fronts can affect air pressure, which in turn causes the altimeter to malfunction.

Heavy rain can also cause the internal electronics to crash, as most standard sports trackers are only splash or drip-proof, rather than fully waterproof.

WHY YOU SHOULD PUSH YOURSELF

THE problem with our 10,000 steps obsession, says Jim Pate, is the low intensity of the exercise.

‘ If you’re starting from zero, 10,000 steps is fine,’ he says. ‘But if you want to see improvements in your fitness and body mass, you need to do more than walking.’

In fact, he points out that NHS guidelines recommend 150 minutes — or 30 minutes five times a week — of ‘moderate’ exercise, which is much more than a daily dawdle to and from the office.

‘It’s a nice routine to get into, but there’s no intensity to the exercise,’ Jim adds. ‘This alone isn’t enough.

If you push yourself so hard you’re sweating and out of breath, you’re putting your respiratory system under stress and this encourages it to get stronger.

‘high-intensity exercise is critical to improving your lung and heart health. It also pumps endorphins — feel-good hormones — around your body, which act on the pleasure pathways in your brain and can have a profound effect on your mood.’

THEY DON’T KNOW WHAT YOU DO . . .

Your sports tracker may have special settings for different activities, but don’t be fooled: most of them simply detect movement and don’t know what you’re doing unless you tell them.

The devices use an accelerometer or mercury switch — both movement sensors — to track the motion and orientation of your body, sometimes coupled with a GPS chip to detect location. This means sports with fluid arm or leg movements — such as cycling, swimming, skiing or rowing — can confuse the readings. Nor do they have any idea how hard you’re working. Whether you’re walking along swinging your arms or lifting 30kg weights, the readings they give will be exactly the same.

. . . AND IT’S EASY TO TRICK THEM

Such drawbacks mean trackers are vulnerable to being ‘cheated’ by users so desperate to reach their 10,000- step goal that they will do anything to get there.

Swinging the band around your finger or shaking it are common ‘hacks’ to trick the device — but online users have reported even more imaginative methods, from attaching their sports tracker to their dog’s collar to setting it on top of a washing machine or attaching it to an electric drill.

There is evidence that wearing the device on public transport can make it think you are running at a steady pace, while some users say the vibrations of a moving car or motorbike help them rack up thousands of fake steps. ‘If you really want to cheat your tracker, move it up and down, rather than side to side,’ says Jim Pate. ‘You’ve got to do it at the same pace as your natural stride, though, or it will realise something’s up.’