That page doesn't say specifically, but my recollection is that it's otherwise every 10 minutes if you're still. In non-workout mode they don't measure heart rate if you're moving; presumably not accurate enough.
All-day heart-rate monitoring can only be claimed by devices with a battery life of at least a day.
right... I mean "continuous" on a digital device is still going to have some sample rate... Apple Watch has a 10 minute sample rate most of the time and some higher sample rate when they are doing "continuous" monitoring during a workout. Fitbit must have a great way to store that data if they really are doing "continuous" monitoring all day.
That page doesn't say specifically, but my recollection is that it's otherwise every 10 minutes if you're still. In non-workout mode they don't measure heart rate if you're moving; presumably not accurate enough.
All-day heart-rate monitoring can only be claimed by devices with a battery life of at least a day.