As the leaders of China and Russia walked to the viewing platform at a military parade in Beijing on Wednesday, they made small talk about living forever.

周三，在北京阅兵式上，中俄两国领导人在走向观礼台时，聊起了长生不老。

Xi Jinping, China’s leader, mused that people might soon live to 150. President Vladimir V. Putin of Russia, speaking through a translator, said that organ transplants could allow humans to achieve “immortality.”

中国国家主席习近平感慨人类寿命或将突破150岁。俄罗斯总统普京通过翻译表示，器官移植可以让人类实现“永生”。

The fragments of banter were captured by a microphone and broadcast live by Chinese state news media from the parade celebrating the 80th anniversary of the end of World War II. It was a hot mic moment that shed light on how medical advances are intersecting with geopolitics, given that both Mr. Putin and Mr. Xi, who are both 72, have suggested they may want to stay in power for years to come.

这段闲谈被麦克风捕捉下来，并通过中国官方媒体庆祝“二战”结束80周年阅兵式直播播放了出去。鉴于现年72岁的普京和习近平都曾表示可能希望在未来几年继续掌权，这个无意被捕捉的时刻凸显了医学进步与地缘政治的交集。

Asked about the comments in a news conference later on Wednesday, Mr. Putin confirmed that the conversation had taken place.

在周三晚些时候的新闻发布会上，当被问及上述言论时，普京证实了这番对话的发生。

“Modern health methods,” Mr. Putin told a reporter, “allow humanity to hope” that “life expectancy will grow significantly.” Among those advances, he said, were “medical means, even surgical ones, related to organ transplants.”

普京对记者说，“现代医疗方法让人类有理由期待预期寿命将显著延长。”他说，这些进步包括“与器官移植有关的医疗手段，甚至是外科手术手段”。

Mr. Putin has long been reported to take a personal interest in longevity, and he has tasked his health ministry with increasing life expectancy as a “key priority.” The nuclear energy conglomerate Rosatom, one of Russia’s most important state companies, said last year that it was developing technology to “print” human organs.

一直有报道称普京个人对长寿的问题很感兴趣，他责成卫生部将延长预期寿命作为“首要任务”。俄罗斯最重要的国有企业之一、核能集团俄罗斯国家原子能公司去年表示，该公司正在开发“打印”人体器官的技术。

There is no evidence that replacing people’s organs one by one can extend their life, nor is there any substitute for the human brain, which also undergoes the changes of aging. But Mr. Putin apparently referred to organ transplants as a key to longevity as he chatted with Mr. Xi ahead of Wednesday’s parade.

目前没有证据表明一个个地更换人体器官可以延长人的寿命，人类大脑同样会经历衰老变化，且无法被替代。但在周三阅兵前与习近平交谈时，普京显然将器官移植视为长寿的关键。

The live footage picked up the voices of a translator and of Mr. Xi as the world leaders walked to the viewing platform on Tiananmen, or the Gate of Heavenly Peace, which marks the entrance to the former palace of China’s emperors.

当各国领导人步入天安门观礼台时，直播画面捕捉到翻译人员与习近平的声音。天安门是中国昔日帝王宫殿的入口。

Kim Jong-un, the North Korean ruler, accompanied the pair and appeared to be listening in through another translator.

朝鲜领导人金正恩和两人一同前行，似乎正通过另一名翻译聆听对话。

“People rarely lived to be over 70, but these days, at 70, you are still a child,” a man apparently translating Mr. Xi’s comments for Mr. Putin could be heard saying in Russian.

“过去人们活不过70岁，现在70岁还算孩子，”一名男子用俄语转述习近平的话给普京听。

“Biotechnology is making advances,” Mr. Putin responded, according to the translator, now speaking in Mandarin for Mr. Xi. “There’ll be constant transplants of human organs, and maybe even people will grow younger as they age — even achieving immortality.”

“随着生物技术取得进展，”这名翻译用普通话把普京的回答转述给习近平，“人类器官会不断移植，甚至越活越年轻，甚至会长生不老。”

“It could be that in this century humans might be able to live to 150 years old,” Mr. Xi can then be heard saying.

“有预测呢，本世纪呢，可能可以活到150岁，”随后可听到习近平说。

While Mr. Xi has until now shown none of Mr. Putin’s enthusiasm for publicly discussing any hopes for longevity, he has suggested that he wants to stay in power, and therefore alive, for some time yet, avoiding any hint that he has chosen a successor.

尽管习近平迄今未曾像普京那样热衷于公开讨论长寿愿景，但他暗示希望继续掌权，因此仍需活得更久，而且他尚未透露任何指定接班人的迹象。

“It’s our shared hope that the elderly can be well cared for, happy, and live to a ripe age in good health,” he has said.

“让老年人老有所养、生活幸福、健康长寿是我们的共同愿望，”他曾说。

But during Wednesday’s military parade, Mr. Xi did not entirely hide his age. There was gray visible in his hair — not always the case for Chinese leaders, who sometimes dye their hair luxuriantly black, even in advanced age.

但在周三的阅兵式上，习近平并未完全掩饰自己的年龄。他头发中可见白发——这在中国领导人中并不常见，他们有时会将头发染得乌黑，即便年事已高。

With round-the-clock medical care, Chinese leaders can live for a long time. Deng Xiaoping died at 92, and his successor, Jiang Zemin, died at 96.

得益于全天候的医疗保障，中国领导人普遍长寿。邓小平享年92岁，其继任者江泽民则活到96岁。

Mr. Putin, for his part, engineered a change of Russia’s Constitution in 2020 that would allow him to rule until 2036, when he would be 83. He is fixated on his health, people who know him say, and required those he met face to face during the Covid-19 pandemic to quarantine for as long as two weeks to see him.

普京在2020年修改了俄罗斯宪法，令他可以执政到2036年，届时他将年满83岁。认识他的人说，他非常关注自己的健康，新冠疫情期间，他要求所有面见者必须接受长达两周的隔离观察。