Washington (CNN) President Donald Trump's staunch defense of his own mental acuity this weekend all but ensured the questions mounting about his fitness will increase in the coming week, which is set to culminate Friday with his first known medical exam since taking office.

Coming amid a previously-unheard-of debate over the mental capacity of the country's oldest president at the time of his first election, the yearly presidential physical has attracted renewed attention from a capital now consumed with Trump's mental health. But there is little to indicate the checkup will provide much clarity about the state of Trump's mind.

In a series of tweets dispatched Saturday morning from the frigid Maryland woods, where he was huddling with congressional leaders at Camp David, Trump, 71, declared himself a "very stable genius" and "like, really smart."

Trump was attempting to rebut the claim made in a damaging new book that some of his aides doubt his fitness for office. But he was also speaking to the growing chorus -- mostly from Democrats but also including a few Republicans -- questioning his mental health.

On Friday, Trump is due at the Walter Reed National Military Medical Center in Maryland for a medical exam conducted by the White House physician, Dr. Ronny Jackson, who performed President Barack Obama's last several physicals while he was in office. The White House has said it will provide a readout of the exam once it's complete.

What to expect

But any hopes that the publicly released information will shed light on Trump's mental state appear largely misplaced. A review of the past five presidents' physical exams show only brief mentions of mental health, and none provide a readout of mental health tests.

White House press secretary Sarah Sanders declined to specify details of Trump's physical when she was asked last week whether the exam would include mental acuity tests.

"We'll discuss, as I said when I announced that he was going to be doing the physical, we'll have a readout of that after that is completed and we'll let you know at that time," Sanders said.

Currently, the US Preventive Services Task Force does not recommend older patients without signs of symptoms receive routine screenings for cognitive impairment or dementia, citing insufficient evidence. But the government does require doctors to ask patients over age 65 during the yearly Medicare Wellness Exam whether they've noticed any depression or memory loss. The 71-year-old Trump is not on Medicare and not bound by the requirement.

Scientists have also determined that having a parent or sibling with Alzheimer's increases the risk of developing the disease. Trump's father, Fred, whose photograph sits behind the Resolute Desk in the Oval Office, developed Alzheimer's in his 80s.

What precisely will be disclosed about the President's health isn't yet clear. Trump himself will determine what information to make public, a person familiar with the process of presidential exams said.

The person, who has been involved in past presidential physicals, said the White House Medical Unit typically prepares a summary to give the media after the exam is completed. Because the health information is considered private under federal law, the President himself must sign off on its release.

Doctors who have performed presidential physicals in the past said the task of releasing information that is ordinarily bound by strict privacy rules can prove daunting.

"You have to remember if there is something wrong with a president that kicks him out of office, everyone who comes with him leaves. So everyone wants to keep him in, they want to silence the doctor," Dr. Connie Mariano, who served as White House physician for George W. Bush and Bill Clinton, told CNN in 2015.

Over the past four decades, there has been no single format for releasing information about the President's health. Typical readings have included the President's height, weight, body mass index (which indicates whether an individual is normal weight, overweight or obese), resting heart rate and blood pressure. Past exams have also included details about the commander in chief's vision, thyroid, cardiac rhythms, gastrointestinal system, skin and neurological indicators like cerebellar function, motor functions and sensory systems.

Almost always, the physician conducting the exam will make a general assessment of the President's health, and declare him fit to serve in the office. Past presidents have been largely forthcoming with their medical records, including some embarrassing details like when Bill Clinton's doctor revealed he had hemorrhoids.

Portraits of vigor

Photos: Photos: Presidents take a swing at golf Presidents take a swing at golf – President Barack Obama and Vice President Joe Biden practice on the White House putting green in 2009. Fifteen of the past 18 presidents have played golf. Hide Caption 1 of 11 Photos: Photos: Presidents take a swing at golf Presidents take a swing at golf – President George W. Bush tips his hat after teeing off on the first hole at the Andrews Air Force Base golf course on September 28, 2003. Hide Caption 2 of 11 Photos: Photos: Presidents take a swing at golf Presidents take a swing at golf – President Bill Clinton watches as his first tee shot heads off the course and into the trees at the Farm Neck Golf Club of Martha's Vineyard during a family vacation on August 23, 1999. Known for taking mulligans, or friendly do-over shots, his second attempt landed in the same spot. Hide Caption 3 of 11 Photos: Photos: Presidents take a swing at golf Presidents take a swing at golf – President George H. W. Bush tees off on the fourth hole at Spyglass Golf Course during the AT&T Pebble Beach National Pro-Am on February 28, 1994, in Pebble Beach, California. Hide Caption 4 of 11 Photos: Photos: Presidents take a swing at golf Presidents take a swing at golf – President Ronald Reagan putts a golf ball on Air Force One on November 16, 1985. Hide Caption 5 of 11 Photos: Photos: Presidents take a swing at golf Presidents take a swing at golf – President Gerald Ford plays golf during a working vacation on Mackinac Island in Michigan on July 13, 1975. Hide Caption 6 of 11 Photos: Photos: Presidents take a swing at golf Presidents take a swing at golf – President Richard Nixon and Attorney General John Mitchell play golf at the Los Angeles Country Club in 1969. Hide Caption 7 of 11 Photos: Photos: Presidents take a swing at golf Presidents take a swing at golf – President Dwight D. Eisenhower drives down the fairway at Turnberry golf course during a weekend stay at Culzean Castle on the Ayrshire coast of Scotland on September 5, 1959. Eisenhower often carried a club in the Oval Office and took swings while dictating to his secretary. Hide Caption 8 of 11 Photos: Photos: Presidents take a swing at golf Presidents take a swing at golf – President Warren Harding, left, gets ready to golf on the Piping Rock Golf Links on Long Island, New York, in 1921. He's with Howard Whitney, second from left, president of the U.S. Golf Association; financier Percy Pyne; and industrialist J. Leonard Replogle. Hide Caption 9 of 11 Photos: Photos: Presidents take a swing at golf Presidents take a swing at golf – President Woodrow Wilson plays a round of golf in 1916. He played more golf than any other president, reportedly logging more than 1,000 rounds in his two terms. Hide Caption 10 of 11 Photos: Photos: Presidents take a swing at golf Presidents take a swing at golf – President William Howard Taft, the 27th U.S. president, putts on the green in Chevy Chase, Maryland, on June 28, 1909. He is said to be the first presidential golfer. Hide Caption 11 of 11

During the 2016 campaign, Trump's longtime personal physician Dr. Harold Bornstein released a summary of Trump's health that included his height (6 feet 3 inches) and weight (236 pounds), cholesterol (HDL 63, LDL 94, triglycerides 61), blood pressure (116/70), blood sugar (99), and normal results from liver, thyroid, heart and colon exams.

A review of the official White House readouts of past presidential physicals shows most paint a portrait of vigor -- punctuated by details like workout routines and sports injuries -- without providing details about the mental or emotional state of the patient.

President George W. Bush's first physical was conducted by a panel that included a gastroenterologist, radiologist, optometrist, neurologist, orthopedist, audiologist, dermatologist, otolaryngologist, pulmonologist, urologist, cardiologist and podiatrist -- but no psychiatrist or psychologist, at least one that was publicly disclosed.

That doesn't mean there hasn't been concerns over a US president's behavioral health. Abraham Lincoln was described in contemporaneous accounts as suffering from "melancholy," which modern experts have said was likely clinical depression. John F. Kennedy and Richard Nixon both took medication used to treat anxiety -- along with a cocktail of other stimulants and sedatives.

Ronald Reagan

Like with Trump, some of President Ronald Reagan's aides privately worried their boss lacked the mental fitness to carry out his job. Some considered invoking the 25th Amendment that would relieve him of power. Reagan was 73 when he was re-elected.

Unlike Trump, Reagan vowed when he was candidate to undergo mental fitness testing, and told reporters that he would resign if any evidence of senility or deterioration emerged.

Reagan's doctors said after he left office that they did perform some cognitive exams during his yearly physicals, including subtracting seven continually starting at 100. The results of those tests were normal, the physicians said.

Reagan, who like Trump faced questions during his presidency about forgetfulness and mental slips, disclosed in 1994 that he had Alzheimer's. He and his doctors maintained he hadn't shown signs of the disease until after he left office.

In defending himself against accusations of mental instability this weekend, Trump referred to his Republican forebear.

"The Democrats and their lapdogs, the Fake News Mainstream Media, are taking out the old Ronald Reagan playbook," he wrote on Saturday.

On Sunday, he went on: "Ronald Reagan had the same problem and handled it well. So will I!"