Almost three quarters of UK adults said they felt overwhelmed at some point in the last year (2018). That’s a staggering 51m people! So it’s really important to find effective ways to help people manage stress. Exercise and physical activity can make a big difference, so activity trackers and apps that help people to move more could potentially have a major role to play, but not much is known about whether they really work as a stress-management aid, and if they do, what the crucial features are. Nora Ptakauskaite, a PhD research student at UCL, has been finding out.