Nov. 9 (UPI) — Police are investigating an incident in which 25 runners in the Santa Barbara, Calif., Half Marathon and 5K were hospitalized with unusual symptoms.

The runners fell ill Sunday and were treated at Santa Barbara Cottage Hospital and Goleta Valley Cottage Hospital. Cristina Cortez, Cottage Health public relations manager, said the runners shared “similar symptoms.”

The hospital is investigating whether the symptoms are due to illness, heat or “other factors.”

“We have a larger than expected number of emergency visits that are tracked to participants in this morning’s organized run in Santa Barbara,” Cortez said in a statement.

The Santa Barbara Police Department advised participants in the marathon and 5K to seek medical attention if they are feeling ill. The department also asked anyone with information or runners who have experienced unusual symptoms to call Sgt. Andre Miller at 805-897-2330.

David Monico, director of the marathon and 5K, said in an interview that the heat and number of participants may be factors.

“In years past, we’ve had overcast skies or less warm temperatures this time of year, so we have not had this many transports, but there’s always a handful,” he said. “But this year, it was more than we’ve had in the past. We also had more runners than we’ve had in the past as well.”

About 7,500 people participated in the event, which started at 7 a.m. PST.