US Vice-President Kamala Harris is in "excellent health" and "possesses the physical and mental resiliency" required to serve as president, her doctor said in a letter released on Saturday that summarises her medical history and status.

Dr Joshua Simmons, a US Army colonel and physician to the vice-president, wrote that Ms Harris, 59, maintains a healthy, active lifestyle and that her most recent physical last April was "unremarkable".

She "possesses the physical and mental resiliency required to successfully execute the duties of the Presidency, to include those as Chief Executive, Head of State and Commander in Chief," he wrote in a two-page letter.

Ms Harris's presidential campaign hopes to use the moment to draw a contrast with Republican candidate Donald Trump, who has released only limited information about his health over the years, according to a campaign aide who spoke on the condition of anonymity.

The aide said the campaign hopes that highlighting Ms Harris's comparative youth and mental acuity with Mr Trump's more advanced age and tendency to meander, along with the differences in transparency between the two, will help convince undecided voters she is more fit for office.

Dr Simmons, who has been Ms Harris's primary care physician for the past three and a half years, said the vice-president has a history of allergies and urticaria, also known as hives, for which she has been on allergen immunotherapy for the past three years.

He said Ms Harris's latest blood work and other test results were "unremarkable".

"She eats a very healthy diet. She does not use tobacco products and drinks only occasionally and in moderation."

The report also notes that Ms Harris wears contact lenses for mild nearsightedness; her family history includes maternal colon cancer; and she is up to date on preventive care recommendations, including having a colonoscopy and annual mammograms.

As the vice-president's office released the medical report, her campaign highlighted recent media reports raising questions about Mr Trump's health and mental acuity, and his failure to provide information about his health status and medical history.

Mr Trump, 78, eagerly questioned President Joe Biden's health when the 81-year-old president was seeking re-election earlier this year.

Since Mr Biden was replaced on the ticket with Ms Harris, Mr Trump's own health has drawn more attention.

Mr Trump has released very little health information, including after his ear was grazed by a bullet during an assassination attempt in July.

Last November, Mr Trump marked Mr Biden's birthday by releasing a letter from his own physician that reported the former president was in "excellent" physical and mental health.

However, the letter, posted on Mr Trump's social media platform, contained no details to support its claims — measures like weight, blood pressure and cholesterol levels, or the results of any test.

A physician who wrote a glowing review of Mr Trump's health in 2015, including a line that Mr Trump would be 'the healthiest individual ever elected to the presidency" at the time, later said Mr Trump himself had dictated the letter.

ABC/Wires