is waking abruptly dangerous?

Question

To be more specific, is being woken up suddenly out of a sound sleep and having to jump out of bed each morning to shut off an exceedingly loud alarm clock across the room bad for your heart and body?

Answer 1

When you get up, body is just preparing to send more blood to brain. BUt if you get up suddenly and start running,. blood flow to brain may suffer, causing dizziness/blanking to some. If caratoid arteries have suffered arteriosclerosis, then this is often experienced.
It is always better to first turn to side, use your hand to support yourself while getting up first in sitting position and then stand by putting legs first to ground and get up slowly, which allows blood flow to adjust.
This is the procedure yoga teachers advise after shavasana, a yogasana close to deep sleep.

Answer 2

no