President Biden began using a continuous positive airway pressure (CPAP) machine in recent weeks to improve his sleep quality, the White House confirmed Wednesday.

“Since 2008, the President has disclosed his history with sleep apnea in thorough medical reports. He used a CPAP machine last night, which is common for people with that history,” deputy press secretary Andrew Bates said in a statement.

Reporters had noted Wednesday morning there were lines visible on Biden’s face as he stopped to field questions before departing the White House for remarks and a fundraiser in Chicago.

A CPAP machine is typically used to help treat those with sleep apnea. It uses a hose connected to a mask to deliver steady airflow to help an individual breathe while they sleep, according to the Mayo Clinic.

It was disclosed when Biden was running for vice president on the Democratic ticket in 2008 that he dealt with recurring issues with sleep apnea, which is when an individual’s breathing becomes shallow or pauses while sleeping.

News of Biden’s CPAP machine was first reported by Bloomberg.

Sleep apnea affects roughly 5 percent to 10 percent of people worldwide, according to the Cleveland Clinic. It is most common in adults over 60.

Biden, who is 80, has faced persistent questions among voters about his age as he seeks a second term in the White House. 

A Saint Anselm College poll of New Hampshire primary voters released Tuesday found that 70 percent of respondents indicated they are concerned about Biden’s age, even as a large majority said they supported him over Democratic challengers Robert F. Kennedy Jr. and Marianne Williamson.

Biden underwent an annual physical exam in February, and his White House doctor determined he “remains a healthy, vigorous, 80-year-old male” who is fit for the job of the presidency.