I don't have any links to hand but I'm fairly darn certain that arrhythmias start showing up way before anyone gets to 25 cups per day, not to mention fluid bal

I don't have any links to hand but I'm fairly darn certain that arrhythmias start showing up way before anyone gets to 25 cups per day, not to mention fluid balance/kidney issues, which can lead to congestive heart failure. TLDR; arterial stiffness is only one measure of "heart health".