Wearable tech – currently dominated by intelligent watches – is a multi-billion dollar industry with a sharp focus on health tracking.

Many additional expense products claim to accurately track exercise routines, body temperature, heart rate, menstrual pattern and sleep patterns, among others.

Health Secretary Wes Streeting has talked about a proposal to provide wearables to millions of NHS patients in England, enabling them to track symptoms such as reactions to cancer treatments, from home.

But many doctors – and tech experts – remain cautious about using health data captured by wearables.

I’m currently trying out a intelligent ring from the firm Ultrahuman – and it seemed to recognize that I was getting ill before I did.

It alerted me one weekend that my temperature was slightly elevated, and my sleep had been restless. It warned me that this could be a sign I was coming down with something.

I tutted something about the symptoms of perimenopause and ignored it – but two days later I was laid up in bed with gastric flu.

I didn’t require medical assistance, but if I had – would the data from my wearable have helped healthcare professionals with my treatment? Many wearable brands actively inspire this.

The Oura intelligent ring, for example, offers a service where patients can download their data in the form of a update to distribute with their doctor.

Dr Jake Deutsch, a US-based clinician who also advises Oura, says wearable data enables him to “assess overall health more precisely” – but not all doctors consent that it’s genuinely useful all of the period.

Dr Helen Salisbury is a GP at a busy habit in Oxford. She says not many patients arrive in brandishing their wearables, but she’s noticed it has increased, and it concerns her.

“I ponder for the number of times when it’s useful there’s probably more times that it’s not terribly useful, and I worry that we are building a population of hypochondria and over-monitoring of our bodies,” she says.

Dr Salisbury says there can be a large number of reasons why we might temporarily get abnormal data such as an increased heart rate, whether it’s a blip in our bodies or a device malfunction – and many of them do not require further investigation.

“I’m concerned that we will be encouraging people to monitor everything all the period, and view their doctor every period the machine thinks they’re ill, rather than when they ponder they’re ill.”

And she makes a further point about the psychological use of this data as a benevolent of insurance policy against shock health diagnoses. A nasty cancerous tumour for example, is not necessarily going to be flagged by a watch or an app, she says.

What wearables do is inspire excellent habits – but the best communication you can receive from them is the same advice doctors have been giving us for years. Dr Salisbury adds: “The thing you can actually do is walk more, don’t drink too much alcohol, try and maintain a well weight. That never changes.”

The Apple Watch is reported to be the globe’s best-selling intelligent watch, although sales have slowed lately.

Apple didn’t comment, but the tech giant uses factual stories of people whose lives have been saved because of the heart tracking function of the device in its marketing, and anecdotally I have heard plenty of those too. What I haven’t heard however, is how many cases of untrue positives there are.

In many cases when patients now their data to healthcare professionals, clinicians prefer to try to recreate it using their own equipment, rather than simply depend what the wearable has captured.

There are several reasons for this, says Dr Yang Wei, associate professor in wearable technologies at Nottingham Trent University – and they’re all very practical.

“When you leave to hospital, and you assess your ECG [electrocardiogram, a test that checks the activity of your heart], you don’t worry about power consumption because the machine is plugged into the wall,” he says.

“On your watch, you’re not going to assess your ECG continuously because you drain your battery straight away.”

In addition, movement – both of the wearable itself on a wrist, for example, and general movement of the person wearing it – can “make noise” in the data it collects, he adds, making it less reliable.

Dr Wei points to the ring on my finger.

“The gold standard to assess the heart rate is from the wrist or direct from the heart,” he says. “If you assess from the finger, you’re sacrificing accuracy.”

It is the role of software to fill in such data gaps, he says – but there’s no international standard for wearables here – for either the sensors and software that power wearable devices, or for the data itself, and even what format it is gathered in.

The more consistently a device is worn, the more accurate its data is likely to be. But here’s a cautionary account.

Ben Wood was out for the day when his wife received a series of alarming notifications from his Apple Watch, telling her he had been in a car crash. It advised her to text him rather than call because he may require to keep the line obvious for the emergency services.

The alerts were genuine, and sent to her as his emergency contact – but in this case unnecessary. Ben was out at a race track driving some quick cars. He admitted that he “wasn’t very gifted” at it – but said he felt secure at all times.

“The boundaries between incident and alert require to be managed carefully,” he wrote in a blog post. “I’m curious to view how device-makers, emergency services, first responders and individuals ponder about this technology in the upcoming.”

Pritesh Mistry, digital technologies fellow at the Kings fund, agrees that there are significant challenges around folding current patient-generated data into our healthcare systems, and adds that the talk has already been going on for several years in the UK without any obvious resolution.

He says there’s “a excellent case to be made” for the use of wearables in the UK government’s current drive to push worry out of hospitals and into throng settings.

“But without that underpinning foundation of technology enablement in terms of the infrastructure, and supporting the workforce to have the skills, knowledge, capacity and confidence, I ponder it’s going to be a test,” he adds.