My Fitbit Air test revealed the flaws of calorie counting with a health tracker - here's why ...

Your heart beats around 100,000 times every day. Heart rate is a key marker of cardiovascular activity and an important vital sign. But your pulse is not as steady as a precision clock – nor would you ...

When the first Apple Watch made its global debut, Apple said it was a product that would enrich people's lives and encourage them to adopt a healthier lifestyle, thanks in part to a heart rate sensor ...