MindHow your heart rate variability can offer an insight into your mind Smartwatches commonly use heart rate variability to monitor stress. Columnist Helen Thomson explores what this metric actually tells us, and whether it could also predict and diagnose depression – and help improve your mental health more generally Comment
SpaceCPR in space could be made easier by chest compression machines Performing CPR on a space station in microgravity involves doing a handstand on a person's chest and pushing against the walls with your legs – but now researchers say there is a better way News