> Once you're around 80 it'll wake up anyone

Source? I haven't been able to find info on this. I get resuls on nocturnal tachycardia and such. Nothing on elevating a sleeping person's heart rate and observing the result, though.

To be clear, if you implanted a lead, you might not wake them up. It's the mechanism by which you would raise their heartrate that would wake them - the same things that elevate heartrate from external stimulation would also cause cortical arousal.