I tested the 4 most popular health trackers for a year - and they're all on sale for Prime Day

From smart rings to smartwatches, these are the health trackers I rely on daily - and always recommend.

I tested the 4 most popular health trackers for a year - and they're all on sale for Prime Day
From smart rings to smartwatches, these are the health trackers I rely on daily - and always recommend.