(As a reference, the average life expectancy in that period was lower than today, not because the people then died at an earlier age but because of the high infant mortality rate; the average life of an adult male was not significantly shorter than that of today.
(ちなみに、近世以前の平均寿命の短さは乳幼児死亡率の高さが主な原因であり、成人男子の平均余命だけを考えれば現代人より著しく短い訳ではない。