A 38-year-old County Jail inmate who was working out on a weightlifting machine in the jail’s exercise yard collapsed Saturday night and later died, apparently of an aneurysm, authorities said.

Arthur Weygandt of Imperial Beach, who was being held on suspicion of spousal rape, collapsed shortly after 8 p.m. Saturday and was taken by ambulance to Tri-City Hospital in Oceanside, said Sgt. Kate Nolan, a spokeswoman for the San Diego County Sheriff’s Department.

Jail officials said Weygandt collapsed suddenly and that doctors at the hospital said he had suffered a “probable aneurysm.” He died at 11:42 p.m. An autopsy was scheduled for today.