Recently, we’ve been hearing reports from Twitter and Reddit that
the Apple Watch’s plethysmograph sensor plays not-so-nicely with
wrist or arm sleeve tattoos. The ink pigmentation interferes with
the sensor’s ability to read your heart rate — and with it, the
Watch’s ability to assess whether or not it’s maintaining skin
For those wondering: natural skin pigmentation doesn’t block light
the same way artificial ink pigment or even scar tissue does, so
you shouldn’t run into a problem if your skin is naturally darker.