Willie Nelson left the stage with breathing problems on Sunday night (Aug. 14) in Utah. The singer had just begun his set when he abruptly cut the show short.

Later Nelson would explain that the altitude got the better of him. In a tweet sent just after midnight Monday morning (Aug. 14), Nelson said he was feeling better and headed for lower ground. Sunday night's show was at the USANA Amphitheater in Salt Lake City.

Billboard sources several people on the scene in saying Nelson had just begun the concert when he left the stage. He was treated at a local hospital, the outlet reports. The singer's team has not confirmed this.

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It's not the first time the 84-year-old has struggled to find the air to perform, although rarely has he had to cancel or prematurely end a concert because of it. In August 2012 he reportedly canceled because he was having trouble breathing. Untrue rumors of a grave illness earlier this year cited a struggle to breathe as the reason he'd canceled shows. While his publicist shot down reports that he was deathly ill, she did concede he had a bad cold. Several weeks later he appeared to struggle with his breathing during performances at the Merle Haggard tribute concert at the Bridgestone Arena in Nashville.

Over the years Nelson has had to cancel or postpone sporadic shows for health reasons, yet he continues to keep a packed touring schedule. This year he has shows planned through November. In May Nelson released yet another studio album — God's Problem Child debuted at No. 1 on the Billboard Top Country Album chart.

Nelson's next scheduled concert is at Mountain City Winery in Saratoga, Calif., on Aug. 15.

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