Not sure about Paleolithic, but this source claims average lifespan for hunter gatherers at 70 years.  Not bad considering one gets to hang with their friends and family, have low stress, work less.<p><a href="http:&#x2F;&#x2F;www.anth.ucsb.edu&#x2F;faculty&#x2F;gurven&#x2F;papers&#x2F;GurvenKaplan2007pdr.pdf" rel="nofollow">http:&#x2F;&#x2F;www.anth.ucsb.edu&#x2F;faculty&#x2F;gurven&#x2F;papers&#x2F;GurvenKaplan2...</a>