Originally Posted by guadzilla

It isnt hard in the sense that your legs start burning or your HR goes through the roof. But it requires a lot of mental focus. When you do a normal Z2/endurance ride, you often take short micro-breaks and coast for a second or two, or let your power drop a little. When you are riding without any of these pauses, your legs definitely notice it, and you need concentration to avoid lapsing into this.

My earlier approach to Z2 rides was just got out and ride and as long as my average W for the ride were in the zone, it was good. But this would result in a lot of time in Z1. Now, my Z2 ride is almost entirely in Z2, and the benefit of that has been really obvious.