An unscheduled weekend visit to hospital has raised suspicions about the health of President Donald Trump .

White House officials have insisted the president was merely getting a head start on his annual medical when he visited the Walter Reed National Military Medical Centre on Saturday.

For any president, a sudden trip to the hospital would raise questions, but such scrutiny was magnified with a president who has a history of exaggeration and playing loose with the facts, giving sceptics room to run with their own theories.

The one thing you can be absolutely sure of is this was not routine and he didnt go up there for half his physical, tweeted Joe Lockhart, a press secretary under then president Bill Clinton, who was himself impeached for perjury and obstruction.

What does it mean? It means that we just wont know what the medical issue was.

The presidents medical appointment was not listed on his Saturday public schedule, and his last medical was just nine months ago.

Press secretary Stephanie Grisham said the 73-year-old president was anticipating a very busy 2020 and wanted to take advantage of a free weekend in Washington to begin portions of his routine check-up.

Grisham followed up on Monday night tweeting a memorandum from the presidents physician, US Navy Commander Sean Conley, who described Saturdays visit as a routine, planned interim checkup as part of the regular, primary preventative care he received throughout the year.