Excellent podcast episode with @Coach.Neal.H and @Coach.Mac.C explaining what happens physiologically as we get older and how we should consider training for endurance sports as we age. See Episode 44:
Spoiler: Recommendations are to do more intense workouts, strength work all year round, and recover more. All of this is consistent with this training article: Faster Masters/ How to Get & Stay Fast Over 40 from The Sufferfest.