How fast does your heart beat? It’s a tough question to answer, because our heart rate changes all the time depending on what we’re doing and how our body is behaving. However, [Ludwin] noted that ...

Everything you need to know about photoplethysmography (PPG), the technology behind heart rate measurements in fitness watches and smart rings. When you purchase through links on our site, we may earn ...

Anne R. Crecelius does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond ...