The 76-year-old performer canceled a Saturday performance in Charleston, S.C., for unspecified health reasons. He had resumed touring this year after canceling a series of shows in October.Jimmy Buffett, the singer-songwriter who has built a lucrative lifestyle empire on the basis of beach-bum anthems like “Margaritaville” and “It’s 5 O’Clock Somewhere,” canceled a show scheduled for Saturday in Charleston, S.C., after he was hospitalized for an unspecified illness.Mr. Buffett, 76, said in a statement on Thursday that he had a “sudden change of plans this week” after returning from a trip to the Bahamas.“I had to stop in Boston for a checkup but wound up back in the hospital to address some issues that needed immediate attention,” he said. “Growing old is not for sissies, I promise you.”Mr. Buffett said that he would perform again when he is “well enough.”A representative for Mr. Buffett responded to a request for information about his condition by referring to his statement and declined to comment further.It was unclear on Friday how long Mr. Buffett would refrain from performing. There were no events listed on his tour page, which told Parrotheads, as Mr. Buffett’s fans call themselves, to “stay tuned” for upcoming show announcements.Nick Pezzorello, the president of a Charleston-based Jimmy Buffett fan club, said that the Lowcountry Parrothead Club wished Mr. Buffett a “speedy recovery” so that his fans “may enjoy and celebrate his music and lifestyle for many more years to come.”“We will anxiously await his return to the Holy City,” Mr. Pezzorello said, referring to Charleston.It was the second time in seven months that Mr. Buffett has had to reschedule shows because of his health. Citing “health issues and brief hospitalization” in September, Mr. Buffett canceled five shows that had been planned in Las Vegas, San Diego, Salt Lake City and Nampa, Idaho, in October.“On doctor’s orders, he must take this time to recuperate and heal,” an announcement on Mr. Buffett’s website said in September.Mr. Buffett was soon back on the road, performing monthly since February. He rescheduled and performed two shows in Las Vegas in March and one in San Diego in early May. He also played in Key West, Fla., and Phoenix.Last month, his hit “Margaritaville” from the 1977 album, “Changes in Latitudes, Changes in Attitudes,” was among 25 recordings that were added to the National Recording Registry.The registry, which is part of the Library of Congress, designates recordings that are “culturally, historically or aesthetically significant” and “worthy of preservation for all time.”When “Margaritaville” was released, the song stayed on the sales charts for months, “scoring with pop and country audiences alike, as well as teenagers and adults,” the Library of Congress said in a statement in April.The song celebrates a life of sunny leisure and frozen drinks, from the opening lines, “nibblin’ on sponge cake, watchin’ the sun bake,” to its earworm refrain, “wastin’ away in Margaritaville, searchin’ for my lost shaker of salt.”“Today, its lyrics are as memorized as any song in history,” the Library of Congress said, adding that the song is “as well known and omnipresent as ever — a regular component of bars, beach parties, karaoke and any place cool vibes are required.” More