There is now a huge range of sports and fitness wearables on the market to measure everything from heart rate to haemoglobin. Researchers at Queensland University of Technology have comprehensively tested 87 of them, and have published their findings.

The study, led by Dr Jonathan Peake and Professor Graham Kerr from QUT’s Institute of Health and Biomedical Innovation, found 95 percent of these devices had not been formally validated by their makers, and in the absence of such testing they say consumers should exercise caution when purchasing wearable technology.

“Most of the health and performance technologies that we have reviewed have been developed based on real-world needs, yet only a small proportion has been proven effective through rigorous, independent validation,” they say. “Many of these technologies described in this review should therefore be classified ‘emerging’ or ‘promising’.”

The detailed findings have been published in a paper A Critical Review of Consumer Wearables, Mobile Applications, and Equipment for Providing Biofeedback, Monitoring Stress, and Sleep in Physically Active Populationsin Frontiers in Physiology.

Kerr said the research did not suggest the devices could not be useful, but  “we do have to be mindful of what supporting evidence there is that they will accurately do what they say they will do.”

The researchers studied device falling to six categories:
- devices for monitoring hydration status and metabolism;
- devices, garments, and mobile applications for monitoring physical and psychological stress;
- wearable devices that provide physical biofeedback (eg, muscle stimulation, haptic feedback);
- devices that provide cognitive feedback and training;
- devices and applications for monitoring and promoting sleep;
- devices and applications for evaluating concussion.

They looked at what the technology was claimed to do; whether it had been independently validated against some accepted standard(s); whether it was reliable and whether calibration was needed, and whether it was commercially available or still under development.

They say that, when assessing the strength of evidence for any given technology, consumers should consider three questions:

- how rigorously has the device/technology been evaluated?
- how strong is the evidence in determining that the device/technology is producing the desired outcomes?
- how much evidence exists to determine that something other than this device/technology is responsible for producing the desired outcomes?

They suggest there would be value for commercial technology companies creating registries of people who use their devices.

“This approach would assist in collecting large amounts of data, which would in turn provide companies with helpful information about the frequency and setting (eg, home versus clinic) of device use, the typical demographics of regular users, and possible feedback from users about devices.”

They add: “It would seem advisable for companies producing health and performance technologies to consult with consumers to identify real-world needs and to invest in research to prove the effectiveness of their products. However, this seems to be relatively rare.

“Budget constraints may prevent some companies from engaging in research. Alternatively, some companies may not want to have their products tested independently out of a desire to avoid public scrutiny about their validity.”