Charlton Heston was 46 in The Omega Man when he played the character 'Robert Neville'.
That was over 53 years ago in 1971.
In 2008 he died aged 84, starring in 155 films in his career, 107 of those after The Omega Man was first released. If he were alive today he would be 100.
In The Omega Man, I think Charlton Heston looks: