Bush has had heart problems since 1991, when he was president. At that time, he entered the hospital with an irregular heartbeat and was diagnosed with Graves’ disease, a thyroid condition.
But Bush celebrated his 90th birthday in June with a tandem parachute jump near his summer home in Maine.
His most recent public appearance was in November at Texas A&M University. He attended with his son, former president George W. Bush.
Bush was president from Jan. 20, 1989, through Jan. 20, 1993.
White House spokesman Eric Schultz, with President Obama on vacation in Kailua, Hawaii, issued a statement saying Obama “has been made aware that President Bush was admitted to the hospital. President Obama and the First Lady send their good wishes to the former President and the entire Bush family during this holiday season.”