US President Donald Trump asked his doctor to put him through a cognitive test in order to address rumours about his poor mental health.

His physician has revealed that he personally asked for the tests to be carried out as part of his first medical check-up as president.

The rumours peaked as President Trump appeared to slur his words during his speech announcing the US decision to recognise Jerusalem as the capital city of Israel last month.

Revealing the results of President Trump’s check up, White House Doctor Ronny Jackson said he had scored a perfect 30/30 in the cognitive tests.

Speaking during a press briefing, Dr Jackson said: "I've got to know him pretty well and I had absolutely no concerns about his cognitive ability."

He added that he did not intend to carry out a cognitive test but did so at the President’s insistence. He said the slurred speech was simply down to a dry mouth.

Earlier this month, in response to allegations about his mental state in Michael Wolff's explosive book Fire And Fury, Mr Trump tweeted that he was a "very stable genius", with "mental stability and being, like, really smart" being his two greatest assets.

Dr Jackson revealed last week that the check-up at the Walter Reed military hospital in Bethesda, Maryland, had gone "exceptionally well," adding that he was "enthusiastic" about sharing further details.

President Trump was said to be in "excellent shape" for an American man of his age, with a "very reassuring" cardiac assessment.

That was despite his height and weight (6ft 3in, and 239lbs) giving him a BMI score that classes him as overweight - and dangerously close to obese.

He has put on 3lbs since his medical records were released during the presidential election campaign in November 2016.

Dr Jackson admitted that he would work with the President in the coming year to improve his diet and increase the amount of physical activity he does, although he said that he considers being on the golf course to be exercise.

President Trump was given an excellent chance of exceeding the average life expectancy for an American man, which the National Centre for Health Statistics places at 78.6.

He was said to be "fit for duty" for the rest of his term, and a second one should he be re-elected in 2020.

Trump took office at age 70, making him the oldest incoming US president.

"I feel very confident that he has a very strong and a very probable possibility of making it completely through his presidency with no medical issues," said Dr Jackson.

When asked how a man whose diet consists of so many hamburgers could be in such good shape, Dr Jackson said: "It's called genetics. Some people have great genes."

President Trump does take medication in a bid to lower his higher-than-recommended cholesterol level of 233, however, as well as daily anti-baldness pills.

Reporting from IRN ...