While Loop in an interrupt

Hey guys!

Got a problem with an interrupt loop:

void setup {
  attachInterrupt(0, ShutDown, RISING);

void ShutDown() {
  while (1) {


I get a very strange behaviour:
When i press my interrupt button, the while loop just seems to loop endlessly without sending my serial 'A', For if i comment out of the while (1) loop, the serial monitor sends the A and executes the breaksOn function as intended.
Any advice here? I can't work it out.

Don't do serial prints inside interrupts. Don't use delay.

And don't use infinite loops.

Until your interrupt handler returns no other interrupts will be dispatched, and the serial port driver uses interrupts.