Sen. Bernie Sanders (I-Vt.) once said that he was going to release his medical records before the Democratic primaries started, but that was before he had a heart attack a few months ago. Now he's backtracking on that pledge.

While appearing on NBC's "Meet the Press" Sunday, host Chuck Todd brought up the pledge and how his heart attack a few months ago has affected his follow through.

"In September of 2019, before your heart incident, you had said the following about your medical records," Todd stated before playing a tape of Sanders pledging to release them.

"The American people have the right know whether the person they're going to be voting for for president is healthy, and we will certainly release our medical records before the primaries," Sanders said on the tape. "It will certainly be before the first votes are cast."

After the clip played, Todd asked Sanders, "The first votes have already been cast, you did not release your medical records. You released a few letters. Nobody interviewed your doctors. You did have a heart attack, apparently. Shouldn't voters see your medical records before Super Tuesday?"

Sanders responded that his campaign had "released as much documentation, I think, as any other candidate."

To that, Todd countered that "no other candidate has had a heart attack."

After the two went back and forth about Sanders' activities on the campaign trail, Todd pointed out that some voters have been concerned about the 78-year-old candidate's age.

"I mean, you can start releasing medical records and it never ends," Sanders replied. "We have released a substantive part, all of our background. We have doctors who have, cardiologists who are confirming that I am in good health. I am in good health."

Sanders was already fielding concerns about his age before he had the heart attack in October, after which his campaign was accused of an "inexcusable three days of silence" for staying keeping people in the dark on what had happened. As he was recovering, the candidate said that he would "change the nature of the campaign a bit," adding that he planned to cut down on rally attendance. In December, he released letters from three doctors, saying that he was fit to serve in office.



When Todd asked what changes he's made since the medical episode, Sanders answered that he's trying to trying to walk a little bit more, but "the schedule doesn't allow me" and "I'm trying to sleep a little bit better, sometimes that's hard. But I'm feeling great."

Now, as his polling numbers in the 2020 Democratic field have started to move him toward the head of the pack, it remains to be seen whether or not his primary opponents will use the backtrack to stymie the senator's momentum.