Gurman: Major ‘Apple Watch X’ redesign coming as soon as next year, testing magnetic band attachments
Gurman: Major ‘Apple Watch X’ redesign coming as soon as next year, testing magnetic band attachments

Gurman: Major 'Apple Watch X' redesign coming as soon as next year, testing magnetic band attachments - 9to5Mac

I have no idea how they would do it but I am stoked about the idea of blood pressure sensors.
There was an article about using reflected light from an led for sensing blood pressure. Similar to how the first pulse rate apps could use the flashlight and camera to see the blood flow through your finger for pulse.