Mike Bloomberg and Bernie Sanders. Photos: Joe Raedle/Getty Images; Brian Blanco/Getty Images

Mike Bloomberg released new information on his heart health Thursday and called on his rival Bernie Sanders to do so as well.

Why it matters: The development, first reported by CNN, continues a public feud between the two candidates, both of whom are 78 years old. The move appears to be an attempt by Bloomberg to make Sanders' health a central issue in the Democratic contest.

Flashback: The senator from Vermont underwent a medical procedure after suffering a heart attack last year.

Details: The former New York City mayor's annual health exam last July included cardiac stress testing and a stress echocardiogram, per a letter from Johns Hopkins University physician Stephen Sisson.

  • The results showed Bloomberg's left ventricular ejection fraction at 60–65%, his left ventricular cavity size and left ventricular function were described as "normal," and his exercise capacity was "excellent," according to Sisson.
  • Between the lines: Ejection fractions measure "how much blood the left ventricle pumps out with each contraction," per the American Heart Association. A normal ejection fraction is between 50 and 70.

What they're saying: "Releasing this single scientific number about heart health could start to put to rest any concerns about Senator Sanders' secrecy about his recent heart attack," Bloomberg campaign spokesperson Stu Loeser told Axios. "Mike Bloomberg's doctor shared Mike's number. Will Senator Sanders ask his doctor to do the same?"

  • A spokesperson for Sanders told CNN the campaign already released documents related to the candidate's overall health. Sanders publicly shared letters from his primary physician and two cardiologists last December.

Go deeper: Bernie Sanders and Democrats' age problem

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Trump campaign removes ad that violated NASA guidelines by showing astronauts

The Falcon 9 rocket carrying the company's Crew Dragon spacecraft launches with NASA astronauts Robert Behnken and Douglas Hurley. Photo: SpaceX via Getty Images

The Trump campaign removed an ad this week that violated NASA guidelines by featuring images of astronauts Bob Behnken and Doug Hurley, who launched to the International Space Station last week, Bloomberg reports.

The state of play: NASA doesn't allow the likenesses of its astronauts to be used in advertisements, and an agency spokesperson told Bloomberg it was unaware of the video until it had been posted.

Energy use declines in Permian Basin offer another glimpse at shale downturn

Reproduced from Energy Policy Institute at the University of Chicago; Chart: Axios Visuals

The downturn in the Permian Basin, the heart of the U.S. oil patch, was large enough to cause a big drop in electricity use there, analysis from a University of Chicago energy think tank shows.

What they did: Their analysis looks at daily declines and fluctuation compared to a pre-COVID baseline (captured above), as well as the average drop-off since mid-March, which is 24%.

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Photo: Barcroft Media / Getty Images

Energy trade associations are denouncing systemic racism that perpetuated the killing of George Floyd by white police officers and other similar acts of racial discrimination in recent years.

Why it matters: The comments show how transcendent this topic is becoming as protestors take to the streets around the country calling for an end to police violence which has disproportionately impacted black people.