Arduino low power

#include <avr/sleep.h>
const byte LED = 9;
/*Riattiva ARDUINO*/
void wake ()
{
  // cancello lo sleep mode
  sleep_disable();
  //disabilito l agestione dell'interapt
  detachInterrupt (0);
}
/*Setup*/
void setup ()
  {
  digitalWrite (2, HIGH);  // enable pull-up
  }
/*Loop*/
void loop ()
{
 /*al primo ciclo accendo il led*/
  pinMode (LED, OUTPUT);
  digitalWrite (LED, HIGH);
  delay (550);
  digitalWrite (LED, LOW);
  delay (50);
  pinMode (LED, INPUT);
  // disabilito ADC
  ADCSRA = 0;
  set_sleep_mode (SLEEP_MODE_PWR_DOWN);
  sleep_enable();
  // Do not interrupt before we go to sleep, or the
  // ISR will detach interrupts and we won't wake.
  noInterrupts ();
  // prendo l'eveno, interapt quando D2 diventa LOWW
  attachInterrupt (0, wake, LOW);
  // turn off brown-out enable in software
  // BODS must be set to one and BODSE must be set to zero within four clock cycles
  MCUCR = bit (BODS) | bit (BODSE);
  // The BODS bit is automatically cleared after three clock cycles
  MCUCR = bit (BODS);
  /*si vuole garantire che la cpu venga spenta solo
  la successiva istruzione dell'attivazione di arduino*/
  /*Fà PARTIRE DI NUOVO IL LOOP*/
  interrupts ();  // one cycle
  sleep_cpu ();   // one cycle

  } // end of loop