Life expectancy at birth of both humans and Neanderthals pre-agriculture (Upper Paleolithic), is also just over 30 years. That works out to be almost exactly 1

Life expectancy at birth of both humans and Neanderthals pre-agriculture (Upper Paleolithic), is also just over 30 years. That works out to be almost exactly 1 billion heartbeats and correlates well with the regressions, according to those charts. Given the above, it is kind of amazing how long humans remain fertile, even without modern medicine [worrying sigh - parents just don't tell you these things].