The 77-year-old singer sought tests after performing, with dehydration cited as a possible cause.
On Saturday, singer Lionel Richie, 77, checked himself into a St. Louis hospital after performing at The Muny, where he appeared to struggle during his final song and performed "All Night Long" while seated.
Medical staff are currently testing Richie for "cardiac-related issues," while TMZ reports doctors are also evaluating the possibility of slight dehydration as a contributing factor.
A similar episode occurred on June 24 in St. Paul, Minnesota, when Richie announced an intermission about 55 minutes in after feeling dizzy, then postponed shows in Chicago and Columbus before returning to perform.
Rolling Stone reported that a source close to the tour said Richie is "doing well," though no official diagnosis or condition has been announced on the record by the singer or his representatives.
The National Institute on Aging notes that balance problems and dizziness are common in older adults and can be caused by medications, balance disorders, or other medical conditions warranting evaluation.