Expert: Michael Jackson went 60 days without real sleep

Los Angeles (CNN) -- Michael Jackson died while preparing to set a world record for the most successful concert run ever, but he unknowingly set another record that led to his death.

Jackson may be the only human ever to go two months without REM -- Rapid Eye Movement -- sleep, which is vital to keep the brain and body alive. The 60 nights of propofol infusions Dr. Conrad Murray said he gave Jackson to treat his insomnia is something a sleep expert says no one had ever undergone.

Propofol disrupts the normal sleep cycle and offers no REM sleep, yet it leaves a patient feeling refreshed as if they had experienced genuine sleep, according to Dr. Charles Czeisler, a Harvard Medical School sleep expert testifying at the wrongful death trial of concert promoter AEG LIve.

If the singer had not died on June 25, 2009, of an overdose of the surgical anesthetic, the lack of REM sleep may have soon taken his life anyway, according to an opinion by Czeisler.