Not sure you have granted public permission to view your training on Garmin Connect. All I got was You do not have sufficient privileges to view the activity with id 220840929
I have a similar problem at age 54, I was hitting my max HR too often, and finally realized that whenever my legs got tired I would shift into an easier gear and spin at a higher cadence which immediately raised my pulse. In other words I shifted the load from my legs to my heart. Well this was fine back when my max pulse was 225, but today I just can't do it anymore. So this last year I have concentrated on increasing leg strength and reducing my cadence.This meant lots of training and intervals gradually reducing cadence and increase speed by using a larger gears. So after one year I have increased my average speed by a couple of mph while still running around 155 avg pulse when pushing hard on 100km or so, and now doing about 22-24mph with an average cadence of 72 (down from 76 last year).