Fitness trackers get you moving but barely budge your health numbers

Wearable devices have moved from gadgets to something close to a standard health care intervention, sold on the promise of promoting healthy behaviour and cutting the risk of chronic conditions like cardiovascular disease and diabetes. Millions of people strap one on assuming the step counts and nudges translate into better health. But motivation to move and measurable improvement in disease outcomes are two different things, and the gap between them had not been carefully checked. This review set out to ask the harder question: when wearables are put through proper trials, do the health numbers actually improve?

The researchers ran a systematic search across PubMed, Web of Science, the World Health Organization's international clinical trials registry, the ISRCTN registry and the Institute of Electrical and Electronics Engineers database, following PRISMA guidelines. They looked for randomised controlled trials or quasi-experimental studies in adults that reported actual health outcomes, published in English up to October 2018. Three investigators independently reviewed the candidate papers and agreed on the final selection. Out of 550 publications extracted, only 6 studies met the criteria for inclusion.

Overall there was little indication that wearable devices provide a benefit for chronic disease health outcomes. Of the 6 studies examined, only one showed a significant reduction in weight among participants using wearables. No significant reduction was found in cholesterol or blood pressure across the trials. Only one study examined haemoglobin A1c, a marker of long-term blood sugar control, and that one did show a significant reduction in older patients with type 2 diabetes. The authors concluded that wearables play a role as a facilitator in motivating and accelerating physical activity, but that current data do not suggest other consistent health benefits.

This review complicates a widely held assumption: that because wearables increase activity, they must also improve health. The evidence says the first part may hold while the second remains unproven. It is worth stressing how thin the trial base was, with just 6 studies surviving from 550 publications, so this is less a demonstration that wearables fail and more a demonstration that nobody had properly shown they work. Open questions remain about longer periods of use, which populations benefit most, and whether pairing a device with coaching or structured programmes changes the picture.

If you own a tracker, this is a reason to think of it as a motivation tool rather than a treatment. The honest reading is that the device can help you move more, and movement itself carries well-established benefits, but the wearable on its own has not been shown to improve weight, cholesterol or blood pressure in most trials. The one bright spot, better long-term blood sugar in older adults with type 2 diabetes, came from a single study. Judge your tracker by whether it actually changes your behaviour, because that is the only pathway through which it has shown any value.