Originally Posted by Sierra_rider

That doesn't surprise me...as it seems, to a highly uneducated person such as myself, like an adaptation to keep the brain oxygenated during hard efforts. Although I'm talking out my rear on that one.

As a rider that is blessed with strong anaerobic capacity, but only a so-so aerobic engine, the zone 2 has been a game changer for my fitness. Between that and actually paying attention to nutrition, my ability to do longer rides and recover well, is the best it's ever been.