I’m currently going through a “base-ish” block and wondering how to best spend my long rides on Saturdays. During the week I try to hit a lot of sweet spot and sometimes a little VO2 when I feel good. On Saturdays, I have 2-3 hours to ride and am pretty comfortable on the trainer for that duration. As far as goals, my target events are currently 6 hour and double century road events, hopefully one day building up to 300-500 mile events. I’m currently 27 and have the first kid on the way in November, so I’m especially looking right now to build a huge base and raise my fitness floor for when I get back on the bike after family life settles in (i.e. gain the longer term adaptations, such as mitochondrial density, if I understand the biology relating to such things correctly).
For Saturdays, I’ve been hitting stuff like 4-5x12 SST into 30-60 minutes of Z2. I’m wondering as I try to increase my ride lengths, should I be going for 100% Z2, or more like 60m Z2/60m of SST intervals/30m Z2? In other words, for the same given duration, for base building is it better to ride all Z2, or do some intensity and then end with Z2? Or put another way, do I lose any of the adaptations gained from long Z2 rides by spending some of that time at higher intensities?