This article is more than 11 months old

This article is more than 11 months old

The blue signs, “Bernie” shirts and chants of “We will win!” were back on Saturday afternoon as Bernie Sanders held his first rally since pausing his campaign for the Democratic presidential nomination due to problems with his health.

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The Vermont senator stopped campaigning at the beginning of October after experiencing chest pains. It was found that he had had a heart attack and was treated for an artery blockage, his campaign said when he was released from hospital.

At 78, Sanders is the oldest major presidential candidate. If elected, he will be the oldest president inaugurated. Asked in Tuesday’s debate how he would “reassure Democratic voters that you’re up to the stress of the presidency”, he plugged the New York event.

“We are going to be mounting a vigorous campaign all over this country,” he said. “That is how I think I can reassure the American people.”

On Saturday, Sanders strolled on stage to Back in Black by AC/DC.

“Let me take this opportunity,” he said, “to thank the many people across this nation who in my time of illness sent me and my family their prayers, their well-wishes and their love. It has meant the world to [my wife Jane] and me, and I thank all of you so very much.”

There is no question that I and my family have faced adversity over these last few weeks, Bernie Sanders

He was, he said, happy to report that he is “more than ever ready to carry out with you the epic struggle that we face today”.

“There is no question that I and my family have faced adversity over these last few weeks,” Sanders said. “The untold story is that people everywhere in this country, in the wealthiest nation in the history of the world, are facing their own adversities.”

Sanders then launched into policy proposals on education, climate change and healthcare. His speech lasted almost an hour.

Though Sanders trails the former vice-president Joe Biden and Senator Elizabeth Warren in most polls, he is beating them in fundraising. From July to September, Sanders raised $25.3m, edging out Warren’s $24.6m and Biden’s $15.2m.

There was no shortage of support in Queensbridge Park. Sanders said the campaign got a permit for 20,000 and had to turn people away. The security company handling the event reportedly said more than 25,000 were there.

One supporter stood out.

“Holy cow!” said Alexandria Ocasio-Cortez. “What’s up, New York City?”

The 30-year-old congresswoman and progressive star gave Sanders a surprise endorsement this week. Her district is less than a mile from Long Island City, where Sanders set his stage. They were joined by New York politicians, the director and writer Michael Moore, and Carmen Yulín Cruz, the mayor of San Juan.

Before she became a celebrity in her own right, Ocasio-Cortez was an organizer for Sanders. Some founders of Justice Democrats, the political action committee that helped organize her campaign, are former Sanders staffers.

“I’m proud to say that the only reason I had any hope in launching a long-shot campaign for Congress is because Bernie Sanders proved that you can run a grassroots campaign in an America where we almost thought it wasn’t possible,” she said.

When I was a baby, my family relied on Planned Parenthood for pre-natal care. Then, Bernie Sanders fought for me Alexandria Ocasio-Cortez

Ocasio-Cortez spoke about her upbringing in a working-class family, her mother born in Puerto Rico and her father in the South Bronx. When she was born, she said, her parents had a one-bedroom apartment with a mattress on the floor and a crib on the closet.

“That’s how we started our American dream,” she said.

Ocasio-Cortez said Sanders’ support for access to healthcare and housing directly benefited her family.

“When you rewind on that story, when I was a baby, my family relied on Planned Parenthood for pre-natal care. Then, Bernie Sanders fought for me. When the federal government decided to discriminate and abandon my queer family and friends, Bernie Sanders was putting his career on the line for us.”

Ocasio-Cortez reflected on her first nine months in Congress.

“Every trick in the book, psychological and otherwise, is used to get us to abandon the working class,” she said. “It has been in that experience … that I have grown to appreciate the enormous consistent, non-stop advocacy of Senator Bernie Sanders.”

Sanders thanked Ocasio-Cortez and said: “It is hard to believe the degree to which she has transformed politics in America.

“I am so delighted that Alexandria is part of our campaign, and I look forward to traveling with her all over this country,” he added.

Facebook Twitter Pinterest Sanders speaks to supporters. Photograph: Johannes Eisele/AFP via Getty Images

Among the fans, Ron Widelec, 38, a teacher from Westchester county, proudly sported a hoodie from 2016.

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“He looked great at the debate, so any concerns I had are gone,” he said. “I invite any of the candidates to try to keep up with him.”

Julia Camacchio, 21, a student based in Middlebury, Vermont, said she was initially on the fence between Sanders and Warren but was persuaded when Ocasio-Cortez and Ilhan Omar, another member of the progressive “Squad”, endorsed Sanders.

“To see that added extra support for me really solidified my vote,” she said.

Multiple supporters suggested Sanders’ health problems, while concerning, were hyped by the media.

“Every time he’s mentioned now, [the media has] to mention the word ‘heart attack’ with his name,” Widelec said. “I think that is a deliberative effort to minimize him.”

Al Merenda, 60, from Newburgh, New York, who was accompanied by his 10-year-old son, said that he had two stents inserted in his heart about 10 years ago: “It doesn’t mean anything, and you’re good to go for another 20 years.

“He’s fine. He’s more than fine. Even if he wasn’t, it’s still a better pick. Even if something happens, you still want him in office.”

• This article was amended on 21 October 2019 to clarify the details of Sanders’ health issues.