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There's a feeling of anticipation. Apparent is the cold breath exhaled by my competitors as they do the "pre-race" shuffle on the starting line.

A rapid flick of the hips.

I'm participating in my local Saturday morning race and I mean business. The countdown begins...

Hold on. I need to start my watch. The same goes for the person beside me.

The person behind us expresses impatience. I won't start until… done! Connection established, I'm off.

In the mele, it's hard to find a wrist without a smartwatch on it. And it's not just us participants who use them.

It's a thriving, multi-billion dollar market. Names like Garmin lead the market, all offering an extensive array of diverse versions to cater to a spectrum of lifestyles. Based on how high tech the device you select, costs can start from £100 to a significant investment.

"It drives me insane, I'm unable to switch off."

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

"Stop telling me about a poor sleep."

A handful of the comments I've received from fellow device users when I ask what they feel about theirs.

A Sea of Statistics

My current opinion on my own device? At this moment, annoying. It's reporting my speed is wrong, leading me to doubt whether the overhead branches along my route are disrupting my GPS connection.

Countless individuals of us attach these compact monitors onto our arms and wear them 24/7, apparently comfortable with the fact they're continuously tracking us.

Long past are the days when we used them solely to give us an idea of our step count. Today, they can analyse our sleep patterns, stress levels, heart rate variability (HRV), our VO2 max.

It's a challenge to find a bodily function they aren't designed to measure.

But do they do what they say they do? And are the data points we scrutinise a faithful picture of reality? Do they enhance our mental and physical wellbeing, or do the plethora of readings and motivational messages just contribute to our daily stresses?

Addiction or Aid?

"I become a a little obsessed with mine," one user reveals.

While she values how her device records her workouts, she finds some of its other capabilities "daunting" at times - a feeling initially realised during a pregnancy.

Until she found out she could adjust the settings, her smartwatch kept telling her she was not being productive enough. In a new phase, the watch keeps telling her she's had a poor sleep score.

"I have a six-month old, it's unnecessary for me to be notified I'm tired," she says. "That fact is all too clearly."

Is it not possible to just stop wearing it?

"I could, theoretically, but I'm in this push-pull dynamic with it," she continues. "I value it for its fitness insights, but I'm unsure whether the additional features it can now do is perhaps excessive for me."

The Technology Behind the Tracking

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

They typically project minute LED lights onto your wrist which can detect pulsation, recording your pulse rate. More advanced devices analyse changes in the bioimpedance that flows through the skin to gauge your recovery state.

The Professional Viewpoint

A professor says that overall for smartwatches, it's a "delicate equilibrium" - while the continuously improving tech could potentially aid early diagnosis, "spotting abnormalities before we notice anything", it could also turn us device users into the "worried well".

He points out that newer wearables can perform tests like medical-grade monitoring, which regularly monitor how normal the heart is. They can flag if someone is experiencing atrial fibrillation (AF), where there is erratic impulses in the heart causing an arrhythmia.

This does not necessarily indicate someone is about to have a cardiac event, but it can give an early warning they might be more vulnerable of a stroke in the future.

But how to understand these numbers is not straightforward. The expert concerns that as additional features are incorporated, people may struggle to fully contextualise their data.

"I remain sceptical that being able to monitor so many things is such a beneficial thing," he says.

A professor studying wearable tech echoes this sentiment. Her work into the effect of wearable tech on a specific group of individuals with health issues suggested a minority of those who were given devices to monitor their condition experienced increased anxiety and were "far more likely to use medical services".

She observed a cycle with her patients - they saw a concerning reading on their watch. They grew concerned. Their heart rate increased. They got increasingly anxious. They re-examined the data, and their reading increased again.

"When people are presented with stats about ourselves that we lack context for then, naturally, we are going to seek clarification," the psychologist says. "We monitor, we re-check - it becomes a feedback loop."