GoKawiilApple Watch Series 12 and Ultra 4 add Theater Mode heart-rate toggle
Apple's new Watch Series 12 and Ultra 4 use a Health Sensing System that samples heart rate every five seconds instead of every five minutes, requiring the optical sensor's green light to flash almost continuously. To avoid that light being visible in dark settings, Theater Mode automatically slows heart rate readings back to five-minute intervals, but a new setting lets users override this and keep continuous measurements.