Vivoactive doesn't have the best heart tracking, especially compared to Apple watches which are the gold standard for it. Someone who can afford an Apple watch should probably go for Garmin Venu 3. Same hybrid model benefits with a better sensor.
I follow The Quantified Scientist on YouTube and he's reviewed both I believe. I think the Vivoactive has the older HR sensor and that's why it performed a bit worse in that category.
