Wearable devices, whether they adopt traditional models such as the  Watch, or get incorporated into smart garments, are tiger country.

Already, Apple has learned that building sophisticated body sensors into its Watch was not the brilliant idea that it first seemed. The four sensors on the back of the  Watch are capable of much more than just returning the occasional heart rate. I explained here how they work over a year ago, and suggested they might do much smarter things like estimate the percentage oxygen saturation of the blood (‘sats’) and the dynamics of skin blood flow.

There are a lot of other assessments which could be made of heart rate (or, rather, beat-to-beat intervals) alone. It can provide early warning of a wide range of heart conditions, some of which could easily be fatal. A bit more controversially, some experts now use the variability in heart rate as an indicator of ‘stress’, and coupling heart rate measurements with details of physical activity can give insights into ‘fitness’ and more.

The  Watch does not measure the electrical activity of your heart (its ECG/EKG), but there are already vests which can, in a far more sophisticated way than you could ever achieve using an exercise chest band, for example. Skin-based sensors are also being developed which can monitor blood glucose (sugar), and many more important substances in the body.

The snag with all these wearable systems is that they so readily become medical devices, those being for the diagnosis, prevention, monitoring, treatment, or alleviation of any disease, injury, or other condition, or for the control of fertility/conception. (Thereby also hangs a long and complex tale on the thorny issue of period-based apps to improve the chances of conception, or to minimise them.)

Thus the term medical device encompasses a huge range of potential products; athletic heart rate monitors only just scrape through, provided that they are only intended for use as an aid to exercise and fitness training in the already healthy.

We rightly insist that medical devices are stringently regulated: if our life might depend on one, we want strong assurance that it will do its job properly, and not mislead medical carers into making bad decisions about our condition or care, injure us in any way, or otherwise compromise our safety.

Unfortunately strict approval of medical devices imposes considerable constraints on their design and manufacture, and imposes significant delays in bringing products to market, and modifying them in any way, including simple things such as software updates. This is good when the device is an intensive care tool such as a ECG monitor, but catastrophic for wearable devices for the consumer market. Tim Cook has recently made it clear that Apple would never consider its Watch as a candidate for approval as a medical device, and it is not hard to see why.

All this leaves us with highly capable technology which innovative developers cannot use, just as those of us with Apple’s wonderful sensors on our Watches can use them for but a tiny fraction of their capability.

None of this is helped by the fact that the EU, US, and other administrative entities each have separate regulations and approval processes. They can’t even agree on the classification of different types of medical device, and pooled together the standards and regulations would fill a few bookcases. Have a glance through Wikipedia’s concise summary, and you can see why bringing a medical device to market is slow, costly, and constraining.

What has been lacking here is a long, hard look at the cost of the regulation of medical devices, and their actual or potential benefit: a cost-benefit analysis.

Many years ago, when I was active in international standard-making, I did a little risk-based analysis comparing the benefits of all water-users wearing a moderately protective buoyancy aid (cheaper and more acceptable than a full-blown lifejacket), and a smaller proportion wearing an all-singing, all-dancing lifejacket, which would give much better protection to the few who would be prepared to wear one. Unsurprisingly, universal use of moderate protection almost invariably came out as being superior.

It is that sort of broad examination that we need to make of these more novel pseudo-medical devices, and come up with international standards (ISO) which will strike the right balance between cost, innovation, and benefit. I don’t think that what we are doing just now is anywhere near the right balance, but is driven primarily by the morbid fear of the extremely unlikely.