He only had himself to blame, Mike Weston thought ruefully as he strapped a Fitbit to his wrist one cold February morning. His company was about to start tracking him 24 hours a day, gathering data on everything from his sleep quality and heart rate to his location and web browsing habits.

"I was really quite grumpy about it, I didn't want to put myself on display like that," he says. But as chief executive of Profusion, a data science consultancy, he had been urging his team of number crunchers to plan more ambitious internal projects — and this was the one they had come up with.

FirstFT is our new essential daily email briefing of the best stories from across the web

For 10 days, Profusion's data scientists used Fitbits and other apps to track 171 personal metrics for 31 staff who volunteered (including the somewhat reluctant Mr Weston). Combing through the data, the analysts found they could group the staff into clusters, based on shared patterns of behaviour. They labelled one group "Busy and Coping"; another "Irritated and Unsettled".

Technology has made it possible for employers to monitor employees more closely than ever, from GPS trackers for delivery drivers to software that tracks which websites office workers visit. Companies such as Profusion think wearable gadgets could open a new frontier in workplace analytics, albeit one that would further blur the lines between our work and private lives.