Motorhead had to call off their concert on Thursday (27.08.15) after frontman Lemmy became ill on stage.
The 69-year-old singer told fans he couldn't breathe and had to abandon his set in Salt Lake City, Utah, after just a few songs.
The band posted a message on Facebook afterwards revealing that the altitude had affected Lemmy.
It read: "The people are great, but the air is just too thin. The high altitude makes it difficult for breathing, and that's what happened with Lemmy tonight in Salt Lake City.
"He feels very bad to have cut the show short, but being that high up, he had some trouble breathing well. Lemmy appreciates everyone's concern. The fans always rally round!"
According to Blabbermouth, Lemmy was also experiencing severe back before going off stage.
Lemmy has suffered with his health for some time and has been told to cut back on drinking alcohol and smoking, but he recently insisted that he is most likely to expire on his tour bus, because that is where he feels "most at home".
He said: "I've had some health scares, I've had to really cut back on smoking and drinking and whatever. But it is what it is. I've had a good life, a good run. I do what I do still. I'm sure I'll die on the road, one way or another."
But the 'Ace Of Spades' hitmaker isn't afraid of death. Asked if it frightens him, he said: "No."