I want to preface this post by stating that I'm 46 years old, 265 pounds and been riding regularly for about a year.
I have been trying to improve how fast I can go in an hour. I have been working on 2 X 20's and I did 18.10 miles in one hour on a flat course on a windless day. For me, that is a big improvement of 15.50 when I first started measuring. I am fairly certain that my LT has improved too. I kept my heart rate at an average of 150 for that hour. I used to only average 130.
I realize I will never be the cycling god I dream of. However, I have found a poster that I have taken as my motto: