Academics at the UK’s University of Salford have uncovered surprising emotional and behavioural consequences linked to activity trackers worn by millions of people worldwide.

The paper, which is the first to examine the conflict experienced by smartwatch users, found some individuals felt a loss of autonomy from using the tracker, beginning to rely on it over and above their own experience.

Users questioned who knew best – themselves or their tracker – if data didn’t seem to match how they felt, for instance when they woke up feeling great but were told by the device that they had slept terribly. In these situations, almost all participants in the study said they would believe the activity tracker rather than their own feelings, seeing it as the expert.

Some also expressed fear of removing their device, worrying if they weren’t wearing it, they wouldn’t know how much activity they had done.

“There was a clear divide in terms of those who had their behaviour guided versus governed by a wearable activity tracker (WAT),” said Gabrielle Humphreys, one of the academics involved in the study. “Typically, if a user was already being active, a WAT increased their motivation, acting as an extra layer of reward. But, if a user was not being as active, this turned into feelings of pressure and guilt. We also saw some users report fears over removing their device, particularly around exercising without these metrics. Users in this situation were asking: ‘How will I know what I’ve done?’ over and over again.”

The team’s findings could have important implications around how activity trackers are used in healthcare services, recommendations around healthy use and the potential long-term negative impact of these devices on people’s ability to listen to our own bodies.

The study was published by PLOS Digital Health at journals.plos.org/digitalhealth/article?id=10.1371/journal.pdig.0001136. For more about the University of Salford, go to www.salford.ac.uk.