🔗 Share this article

There's a feeling of anticipation. Visible is the cold breath coming from my competitors as they execute the "pre-race" wiggle on the starting line.

A swift movement of the hips.

I'm at my local weekly parkrun event and I'm focused. Three, two, one...

Oh, hang on. I have to sort my device. So does the runner alongside me.

The person waiting expresses impatience. I'm not moving until… yes! Connection established, away I go.

During the scramble, it's challenging to see a arm without a smartwatch on it. And this extends beyond us runners who rely on them.

It's a booming, massive sector. Names like Garmin lead the market, each with an wide selection of diverse devices to cater to a spectrum of needs. Based on how feature-packed the model you go for, prices can vary between £100 to a significant investment.

"I find it infuriating, I can't switch off."

"It provides solace… It's like a supporter guiding me."

"Please don't notify me I've had a restless night."

Just some of the responses people have shared from fellow device users when I ask what they feel about theirs.

A Sea of Statistics

My feelings on my own device? Currently, irritating. It's indicating I'm not hitting my target, leading me to doubt whether the overhead branches along my route are disrupting my satellite signal.

Countless individuals of us fasten these little devices onto our wrists and use them all day and night, apparently comfortable with the fact they're constantly recording us.

Long past are the days when we relied on them exclusively to give us an rough count of our daily steps. Currently, they can analyse our nightly rest, blood pressure, heart rate variability (HRV), our VO2 max.

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

But can they do what they advertise? And are the data points we scrutinise a faithful picture of the truth? Do they improve our mental and physical wellbeing, or do the avalanche of measurements and constant notifications just contribute to our sense of overwhelm?

Addiction or Aid?

"I become a a little obsessed with mine," a wearer reveals.

While she appreciates how her device monitors her workouts, she finds some of its other functions "overwhelming" at times - a feeling that became apparent during a major life event.

Until she found out she could change its configuration, her smartwatch kept telling her she was failing to be active enough. Later on, the watch keeps telling her she's had a restless night.

"I am caring for a infant, there's no point to be informed my sleep was poor," she says. "I'm acutely aware all too clearly."

Is it not possible to just stop wearing it?

"I could, theoretically, but I have this push-pull dynamic with it," she explains. "I value it for its workout tracking, I just wonder whether the myriad other functions it can now do is possibly excessive for me."

Inside the Device

Every device of smartwatch has its own novel way of measuring your health metrics and analysing your data, but the vast bulk use detectors on the reverse of the watch.

They usually emit small, green LED lights onto your skin which can detect capillary action, detecting your pulse rate. Higher-end devices detect changes in the bioimpedance that flows through the skin to assess your stress levels.

A Fine Balance

A professor says that in general for smartwatches, it's a "difficult line" - while the ever-evolving tech could realistically aid early diagnosis, "identifying issues before we show symptoms", it could also turn us the tracked into the "worried well".

He points out that some of the latest wearables can perform tests like medical-grade monitoring, which constantly monitor how healthy the heart is. They can flag if someone is experiencing atrial fibrillation (AF), where there is abnormal signals in the heart causing an uneven pulse.

This does not mean someone is imminently going to suffer a heart attack, but it can give an advance notice they might be more vulnerable of a blood clot in the years to come.

But how to interpret these figures is complicated. The expert fears that as additional features are incorporated, people may find it hard to fully comprehend their data.

"I'm not entirely convinced that the ability to monitor so many metrics is such a good idea," he says.

A health researcher focusing on patient behaviour concurs. Research into the influence of wearable tech on a set of individuals with health issues suggested a minority of those who were given devices to monitor their heart health experienced increased anxiety and were "had a higher tendency to use medical services".

She noted a pattern with her patients - they saw a worrying figure on their watch. They felt anxious. Their heart rate increased. They got more worried. They looked a second time, and their heart rate rose further.

"If we see stats about ourselves that we can't properly interpret then, of course, we are going to want to know more," the psychologist says. "We check, we re-check - it becomes a feedback loop."