Josh Hafner

USA TODAY

The 74-year-old Bernie Sanders is in "very good health," his doctor said in a letter issued by Sanders' campaign Thursday.

The letter comes days before Iowa's caucuses and in the wake of a plan by one of Hillary Clinton's allies to call for the Vermont senator's health records to be released.

Sanders, who would be 75 by Election Day, would be the oldest person ever elected president.

"You are in overall very good health and active in your professional work, and recreational lifestyle without limitation," writes Brian P. Monahan, stated as Sanders' doctor of 26 years in the letter.

The letter is dated January 20, days after reports that the founder of a pro-Hillary Clinton PAC, David Brock, had planned to publicly call for Sanders' records ahead of the Iowa caucuses.

Sanders is neck-and-neck with Clinton in Iowa.

Shortly after, Sanders' campaign called Brock's plan a "desperate and vile" attack, Bloomberg Politics notes, and Clinton's own campaign chairman tweeted that Brock should "chill out."

The letter released Thursday details that Sanders' last physical took place Nov. 18, 2015, and the results of the examination were normal. He weighed in at 179 pounds and stood six feet tall.

In the past, Sanders has been treated for various conditions, including gout, hypothyroidism and the removal of superficial skin tumors, the report states.

Sanders' past surgeries include the removal of a vocal cord cyst and the repair of the "left and right side inguinal hernias."

The candidate has no history of cardiovascular disease, a leading cause of death.

Clinton released her records last July. Republican front-runner Donald Trump's physician last month stated he would be "the healthiest individual ever elected to the presidency."

Read the entire letter from Sanders' doctor here.

Doctor says Trump would be 'healthiest individual ever elected to the presidency'