If he wins next month's election, Donald Trump would be the oldest person in US history to be elected president. Yet the 78-year-old Republican nominee refuses to disclose new details about his physical or mental well-being, breaking decades of precedent.

There have been limited snapshots of Trump's health over the last year. After he survived an attempted assassination in July, Texas Rep. Ronny Jackson, a staunch supporter who served as his White House physician, wrote a memo describing a gunshot wound to Trump's right ear.

And last November, Trump's personal physician, Dr Bruce Aronwald, wrote a letter describing him as being in “excellent” health with “exceptional” cognitive exams. He noted that “cardiovascular studies are all normal and cancer screening tests” were negative. Trump had also “reduced his weight.”

But those communications didn't address more fundamental questions about Trump's health, including his blood pressure, exact weight or whether he has continued using previously prescribed medication for high cholesterol — or even what testing he underwent. His campaign has also not disclosed whether Trump has been diagnosed with any diseases or received any mental health care after the assassination attempt.

That's giving his political adversaries, including Democratic rival Kamala Harris, an opportunity to raise questions about his age and ability to execute the duties of the presidency into his 80s.

“It makes you wonder: Why does his staff want him to hide away?” Harris asked recently as she needled Trump for withholding medical records, opting against another debate and skipping an interview with CBS' “60 Minutes.” “One must question: Are they afraid that people will see that he is too weak and unstable to lead America?

Trump's doctors have long been opaque about his health, such as when his team at the White House initially downplayed the severity of his 2020 hospitalisation for COVID-19.

His representatives ignored multiple requests from The Associated Press to provide more detailed information about his status for this story.

Drawing a contrast with Trump

In an effort to draw a contrast with Trump, Harris released a letter from her doctor on Saturday that went into far more detail about her medical history including a list of exams and the results. The letter said she has no heart, lung or neurological disorders, is at low risk for heart disease and up-to-date on cancer screenings. She takes medication for allergies and hives. She wears contact lenses, and her only surgery occurred at age 3, when her appendix was removed during an intestinal-related procedure.

While the letter didn't specify her weight, the 59-year-old vice president was declared to be in “excellent health” and to possess "the physical and mental resiliency” required to serve as president.

Still, it's unclear that age will be a significant factor for voters. Polls found that voters were significantly less concerned about Trump's mental capacity and physical health than they were about President Joe Biden's when he was still in the race. Since Harris replaced Biden on the ticket, Trump's advantage on the issue has diminished.

The dynamic is ironic for Trump, who spent years assailing the 81-year-old Biden's age, depicting him as frail and unable to manage the challenges of the presidency. After a disastrous debate performance in June, Biden's fellow Democrats began openly raising similar concerns, ultimately prompting his decision to withdraw from the race and back Harris.

There's no requirement that candidates release health data. But presidential nominees traditionally disclose medical records voluntarily given the demands of the job, particularly if there are concerns about their age.

In 2008, Republican nominee John McCain opened more than 1,000 pages of medical documents for the public to examine. At 72, he would have been the oldest president elected to a first term. Facing scrutiny over his advanced age in 2019, the then-77-year-old Biden released a three-page note from his doctor.

The last thorough report on Trump's health came in 2019, when he was still president. That checkup classified him as obese with a weight of 243 pounds and a body mass index of 30.4, which raises the risk of heart disease, diabetes and other problems. That report also revealed increased dosages of medication for high cholesterol. While Trump doesn't drink alcohol or smoke, he has long avoided exercise other than golf and loves fast food.

As for his family history, his father had Alzheimer's disease late in life, one potential risk factor.

Trump's allies point to his active public lifestyle as evidence that he's not on the decline.

Trump is a frequent golfer and an engaged host during social functions. He takes questions from the press far more often than Harris. He often speaks for more than 90 minutes at his rallies, standing the entire time and often ignoring the teleprompter.

Trump often rambles through his public appearances

Still, Trump's public appearances are often marked by rambling. He regularly confuses timelines, events and people.

Trump has confused Republican rival Nikki Haley with former Democratic House Speaker Nancy Pelosi. He confused the location of a major military base. He mistakenly said that Hungarian Prime Minister Viktor Orbán led Turkey.

Trump regularly acknowledges questions about his age and health during public appearances. On Sunday in Arizona, Trump mocked critics who declare him “cognitively impaired” because he “mispronounced a word.”

“They say, He's cognitively impaired!” Trump teased. “No, I'll let you know when I will be. I will be someday — we all will be someday. I'll be the first to let you know.”

Without further information, simple life expectancy of the average American man shows Trump has about a 79% change of surviving a four-year term, said aging researcher S Jay Olshansky of the University of Illinois at Chicago, who studies presidential health and echoes the call for candidate medical records. The younger Harris has a nearly 97% chance of surviving a first term in office, he said.

When it comes to the presidency, “it's not about age, it's about function,” Olshansky cautioned.