Steps, stress and sleep: what wearables can measure

Whether in the form of a bracelet, a pair of headphones or a sensor tucked into your underwear, wearables have become ubiquitous in our daily lives. From blood sugar to apnoea, here are the health stats you can measure with these devices. Swiss watchmaker Abraham-Louis Perrelet, credited for crafting the world’s first pedometer or step-counter in 1780, would have probably never guessed that a Japanese marketing campaign urging people to take 10,000 steps a day for better health would permanently influence lifestyle habits from the mid-1960s onwards and make his invention ubiquitous. Today, the number of steps to take in a day is still a driver of health goals (as of 2025, the magic number has been updated to 7,000) and the decade-old Apple Watch, once a luxury pedometer, is a medical device approved by the US Food and Drug Administration (FDA) that alerts users if they are experiencing atrial fibrillation, a type of heart arrhythmia. Last June, US Secretary of Health Robert F.