Dead Legs

We ran a local 10k Road Race last night, a real toughie with a big hill between the 1 and 2 mile mark then 3 shorter but steeper climbs in the last 3 miles. Raced quite well and just ducked under 40 minutes which was a massive relief as I've been racing like a donkey recently!
Today my legs are dead - they just don't want to know!! - I'm sure it's my age - you just don't recover as well the older you get. Well, that's my excuse, and I'm sticking to it!!