If you’re not familiar or indeed already one of the 2.5 million people who wears one, the Oura is a smart ring that was designed in Finland in 2013. It works by hiding sensors inside a plain enough-looking ring (I have the gold finish, but you can also choose silver, black, or rose gold) that track temperature, heart rate, movement, blood oxygen levels, and your respiratory rate. It’s largely considered a ring to track sleep and activity, the readings of which are found in the app on your smartphone, but the really intriguing thing in my experience is the way in which it integrates all those results, giving you a really clear idea of where you’re at overall, meaning that rather than becoming fixated on any particular metric, I just think about whether I’m getting approximately the right amount of rest and activity for my needs and make adjustments accordingly.