Russian President Vladimir Putin and Chinese President Xi Jinping have been recorded on a hot mic discussing how organ transplants and other medical advances could let humans live past 150 years — or even become immortal.

But are these comments by the Russian and Chinese leaders, which were picked up during a Beijing summit on Wednesday, backed by scientific evidence?

Experts in human aging said that some of these ideas remain far-fetched, but serious research is also increasingly revealing more about why we age — and how we could try to stop it.