I would like to work on building my aerobic base by doing some long (40, 50, 60) endurance rides at a slower pace -- MY pace, not trying to keep up (or catch up) with our group. I'll call it my Endurance Aerobic Base-Building Ride, and I'll invite other group members to join me if they wish.
I ride primarily with our group because I enjoy the camaraderie and I don't enjoy long solo rides . However, many of them are stronger with a solid aerobic base and many more miles in the saddle. I'm still playing catch-up since I was off the bike all last year waiting for bi-lateral tennis elbow to heal. I've ridden 1000+ miles so far since late January and completed three (unorganized) 60+ miles and a half-century last weekend. I do OK but the second half of the ride is a struggle for me to keep up and my HR stays in the higher zones. After those rides, my slow resting HR doesn't recover until during the night, but I'm usually like new the next morning. After a tough climb, my HR drops quickly; recently I've seen it drop 30 beats in 20-30 seconds. My fitness is improving but I fear I'm taking things too quickly and putting the cart before the horse.
So, I want to do some long slow flat rides to work on my aerobic endurance, and increase the pace over the coming weeks. An article on aerobic base training at Active.com mentions keeping the HR between 61-80% of max HR.
Does anyone have any suggestions, or anything to share from experience or the current thinking on the HR zones for aerobic base training, esp. in the 50+ group? I am aiming for two events later this year (72 flat miles, and a hilly metric) and want to do well and finish strong. I don't race but I like going fast and doing hills; keeping my pace down will be a challenge.