🔗 Share this article

An atmosphere of building tension. Visible is the chilled vapour coming from my rivals as they perform the "about to run" shuffle on the start line.

A rapid twitch of the hips.

I'm participating in my local 5km community parkrun and I'm serious. The countdown begins...

Oh, hang on. I must sort my device. As does the person alongside me.

The person in the line expresses impatience. I won't start until… there! Signal acquired, away I go.

In the mele, it's hard to spot a wrist without a fitness tracker on it. And this extends beyond us athletes who rely on them.

We're witnessing a booming, multi-billion dollar sector. Companies like Samsung Galaxy lead the market, all offering an broad range of various versions to fit a spectrum of budgets. Depending on how high tech the model you select, costs can vary between £100 to thousands of pounds.

"It makes me crazy, I can't switch off."

"It reassures me… It acts as a supporter guiding me."

"Please don't notify me I've experienced a bad night's sleep."

A small sample of the responses people have shared from fellow tracker enthusiasts when I question what they think of theirs.

A Sea of Statistics

My current opinion on mine? Currently, annoying. It's reporting my speed is wrong, leading me to doubt whether the trees I'm passing under are disrupting my location tracking.

Millions of us fasten these little devices onto our wrists and keep them on constantly, ostensibly comfortable with the fact they're continuously monitoring us.

Gone are the days when we relied on them only to give us an estimation of our step count. Now, they can measure our nightly rest, heart rate, glucose levels, our VO2 max.

It's difficult to find a health indicator they fail to monitor.

But can they do what they say they do? And are the statistics we scrutinise a true reflection of reality? Do they boost our overall health, or do the plethora of metrics and cheerleading alerts just add to our everyday anxiety?

A Complicated Bond

"I find myself getting a a little fixated with mine," an individual confesses.

While she values how her device records her exercise, she finds some of its other functions "excessive" at times - a feeling that became apparent during a significant period.

Until she found out she could change its configuration, her smartwatch kept telling her she was being insufficiently active enough. Now, the watch insists her she's had a bad night's sleep.

"I am caring for a infant, it's unnecessary for me to be told I've not slept," she says. "I know that all too clearly."

Why doesn't she just remove it?

"It's possible, I suppose, but I have this complicated dynamic with it," she explains. "I appreciate it for its exercise data, I sometimes question whether the myriad other functions it can now do is maybe excessive for me."

Inside the Device

Each model of smartwatch has its own unique way of measuring your health metrics and analysing your data, but the most use optical sensors on the underside of the watch.

They commonly shine minute LED lights onto your skin which can observe capillary action, identifying your pulse rate. Sophisticated devices measure changes in the electrical current that runs through the skin to gauge your stress levels.

The Professional Viewpoint

A professor says that for most people for smartwatches, it's a "fine balance" - while the ever-evolving tech could realistically save lives, "spotting abnormalities before we notice anything", it could also turn us watch wearers into the "concerned but fine".

He points out that some of the latest wearables can perform tests like heart rhythm analysis, which continuously monitor how normal the heart is. They can flag if someone is experiencing atrial fibrillation (AF), where there is abnormal electrical activity in the heart causing an irregular heartbeat.

This does not necessarily indicate someone is on the verge of a heart attack, but it can give an advance notice they might be more vulnerable of a heart problem in the long term.

But how to make sense of these readings is complex. The expert concerns that as further capabilities are added, people may not be able to fully understand their data.

"I have some doubts that the ability to monitor so many things is such a beneficial thing," he says.

A health researcher specialising in wearable tech echoes this sentiment. Research into the influence of wearable tech on a specific group of heart condition patients suggested a minority of those who were given devices to monitor their cardiac function experienced greater stress and were "far more likely to use doctor's time".

She noted a pattern with her patients - they saw a worrying figure on their watch. They became worried. Their heart rate rose. They got increasingly anxious. They checked again, and their reading increased again.

"When people are presented with stats about ourselves that we lack context for then, of course, we are going to seek clarification," the psychologist says. "We look, we obsess - it becomes a vicious cycle."