On Tuesday, I did a hard 90-minute ride in class in new zones. At first, I was conservative with zone 4 work, but I did the last set of three zone 4 intervals increasing resistance for each subsequent interval, ending up in the mid-zone 4. It was hard, but felt pretty good.
Today, I was too damn tired from Tuesday and needed a recovery day, so I did easy 30 minutes in zone 1, then climbed off and did core work.
That's 90 for those keeping score at home. I think I'll have a commemorative rode for the 100th day.