US President Joe Biden has begun using a continuous positive airway pressure machine, or Cpap, to address a long-standing problem with sleep apnoea, White House officials said on Wednesday.
"Since 2008, the President has disclosed his history with sleep apnoea in thorough medical reports," White House spokesman Andrew Bates said.
"He used a CPAP machine last night, which is common for people with that history."
Another White House official said Mr Biden had begun using the CPAP machine in recent weeks to improve his sleep quality.
Mr Biden was seen by reporters on Wednesday with marks on his face indicating he had been wearing some type of wide strap. Many CPAP users wear a mask held on by a strap.
Bloomberg News first reported Mr Biden's use of the machine.
Sleep apnoea is a common disorder with brief interruptions of breathing during sleep.
It can cause snoring and daytime fatigue, and can lead to high blood pressure or heart problems, according to the Mayo Clinic.
In the most common form of sleep apnoea, the throat muscles relax, blocking the flow of air into the lungs.
Mr Biden, 80, is the oldest serving US president, and his age and health have been a focus of voters as he seeks a second, four-year term in the 2024 election.
Age is one of several factors that increase the risk of developing sleep apnoea.
Joe Biden is questioned about his age after announcing his bid for re-election
Public opinion polling shows that most Americans have concerns about Mr Biden's age.
In February, his doctor declared him healthy and "fit for duty" after a physical examination.
The doctor's report on Mr Biden's physical examination did not mention sleep apnoea but said he has dealt with "sinus congestion for most of his life", and that "sinus symptoms have improved after several sinus and nasal passage surgeries".
