Former White House cardiologist Dr. Jonathan Reiner has renewed scrutiny over Donald Trump's health after claiming the US president appears unable to stay awake during the day, fuelling another round of online debate about the 79-year-old leader's fitness for office.

Reiner's remarks followed renewed viral clips of Trump appearing drowsy during recent public appearances, includingMemorial Day commemorations at Arlington National Cemetery. While the White House has not publicly addressed the latest comments, the physician warned that chronic sleep problems and daytime somnolence can carry serious medical consequences, particularly in older adults.

Speaking during an appearance shared by political commentator Aaron Rupar, Reiner alleged that Trump 'has severe daytime somnolence' and claimed the president 'appears to struggle to stay awake during the day.'

'He falls asleep very often. He's fallen asleep in the Oval Office on multiple occasions with people talking to him in the cabinet room,' Reinersaid. 'It was concerned yesterday that he might've fallen asleep at Arlington National Cemetery during Memorial Day observances.'

The cardiologist believed that Trump could be suffering from 'chronic insomnia,' which he described as 'a severe illness,' warning that prolonged sleep deprivation may increase the risk of dementia, cardiac complications and cognitive decline in older adults.

'It increases your cardiac risk of having a heart attack or developing congestive heart failure,' he said. 'It can produce a decline in your sort of mental functions, like it could increase depression, anxiety. So it's a real problem.'

Reiner also argued that persistent sleep disruption can effectively age a person cognitively, claiming the condition is 'equivalent to about increasing your age by about three and a half years.'

Trump has been open about his sleep habits, saying he is not a heavy sleeper. According to him, he gets only 4 to 5 hours of sleep at night.

However, one should note that he hasn't been formally diagnosed with insomnia.

Dr. Jonathan Reiner: "The president has severe daytime somnolence. He falls asleep very often. He's fallen asleep in the Oval Office on multiple occasions with people talking to him in the cabinet room, and I was concerned yesterday that he might have fallen asleep at Arlington…pic.twitter.com/e44DRs1rzI

Source: International Business Times UK