Former President Donald Trump on Monday released a letter from his doctor that proclaimed him to be in "excellent" physical and mental health, according to Fox News.

That letter, released on President Joe Biden's 81st birthday, provided a stark contrast with numerous polls in recent months that showed most voters harbor serious concerns about the incumbent president's physical and mental health and capabilities.

Trump's overall health rated as "excellent"

On Monday, former President Trump posted to social media a letter he had received from Dr. Bruce Aronwald, who has been Trump's personal physician since he left the White House in 2021.

"I am pleased to report that President Trump's overall health is excellent," Aronwald wrote. "His physical exams were well within the normal range and his cognitive exams were exceptional."

"In addition, his most recent extensive laboratory analysis remains well within normal limits and was even more favorable than prior testing in some of the most significant parameters, most likely secondary to weight reduction," he continued.

"Cardiovascular studies are all normal and cancer screening tests are all negative," the doctor noted. "President Trump has reduced his weight through an improved diet and continued daily physical activity, while maintaining a rigorous schedule."

Aronwald added, "It is my opinion that President Trump is currently in excellent health, and with his continued interest in preventative health monitoring and maintenance, he will continue to enjoy a healthy active lifestyle for years to come."

Biden's age is a problem for many voters

As noted, the positive letter from former President Trump's doctor was released on President Biden's 81st birthday, which also coincided with the release of a new ABC News poll which found that Biden's advanced age -- he would be 82 if re-elected to a second term and 86 when that term concluded -- is a big concern for roughly three-quarters of the American people.

The pollsters discovered that 74% of voters said Biden was "too old" to run for and serve a second term, a 6% increase from when Biden first launched his re-election campaign in May.

Notably, even though Trump is only about three to four years younger than Biden, only around 50% of voters believed that he was also too old to serve another term as president.

Biden's physical and mental health a significant concern for most voters

However, the age of Presidents Biden and Trump is far less of an issue than the perception among voters of how their advanced age has impacted their physical and mental health, and other polls have shown that Trump enjoys a decided advantage over Biden in that regard.

In mid-September, a CBS News/YouGov poll found that only 28% of voters believed that Biden was "physically healthy enough" to serve as president, and just 33% believed that he had sufficient "mental and cognitive health" to fulfill his duties as the nation's chief executive. By comparison, 55% said Trump was physically healthy enough and 51% said his mental and cognitive capabilities were good enough to be president.

Later that same month, an NBC News poll revealed that a combined 74% of registered voters had concerns about Biden's physical and mental health, including 59% with "major" concerns and 15% with "moderate" worries. Another 12% had "minor" concerns about Biden's health and only 14% had no concerns whatsoever.

Compare that to the NBC News pollsters' findings on voters' views of Trump's physical and mental health status, in which 34% had "major" concerns, 13% had "moderate" concerns, another 13% had "minor" concerns, and 39% had no worries at all about Trump's physical and mental capabilities to serve another term as president.