(CNN) -- New Jersey Gov. Chris Christie checked into a hospital Thursday morning after he had difficulty breathing, the governor's press secretary, Michael Drewniak, said in a statement.
"In line with someone dealing with asthma, he is being given routine tests as a precautionary measure," Drewniak said.
Spokeswoman Maria Comella said Thursday afternoon that Christie is "fully alert and in charge" and that he was expected to leave Somerset Medical Center in the evening.
Comella told reporters that Christie received tests but no formal treatment, and that he would be back to work Friday morning.
She said the governor was able to walk into the emergency room even as he had difficulty breathing.
CNN Political Reporter Peter Hamby contributed to this report.