Metallica drummer Lars Ulrich fears his health will be the catalyst that eventually leads to the end of the heavy rock group - because he won't be able to perform his high-energy routine as he ages.
The rock star insists the group has no plans to split in the near future, but touring will become a problem if he can no longer keep up.
He tells Rolling Stone magazine, "The Rolling Stones, Black Sabbath, Aerosmith, I have nothing but respect for their longevity but (Stones drummer) Charlie Watts isn't playing Damage, Inc. three times a week or playing Whiplash every night.
"This (Metallica) has the potential to go on for a long time. But if somebody's arm, back or neck just says, 'F**k this,' and quits, I don't know..."