Songbird Mariah Carey – the self-proclaimed Queen of Christmas – is quietly panicking that her longtime holiday hit won't dominate the airwaves this year, which would be a blow to her ego and her wallet,

Holiday songs from Justin Bieber, Mariah Carey and Michael Bublé are on the top 10 list for best Christmas songs to listen to during moderate- to high-intensity workouts, according to a study conducted by health experts at MyBodyTutor.

Fans congratulate the singer for her hit "All I Want for Christmas is You" for spending 20 weeks as the No. 1 song on Billboard's Hot 100.

This week's Five Burning Questions looks at Mariah Carey's "All I Want for Christmas Is You" and Wham!'s "Last Christmas" leading the Hot 100.