Zone 2 training
Zone 2 training is steady, low-intensity aerobic exercise — easy enough to hold a conversation, usually just below your first lactate threshold. It builds the aerobic base that endurance performance is built on, with little fatigue.
How to find your zone 2
On the bike, zone 2 is roughly 56–75% of FTP. In heart rate terms it is often around 60–70% of maximum heart rate, though the exact band depends on the zone model you use. The talk test is a good check: you should be able to speak in full sentences.
Why it works
Easy aerobic volume drives adaptations — more mitochondria, more capillaries, better fat use — that let you go faster at the same effort. Because it is easy to recover from, you can do a lot of it. Many endurance athletes spend most of their training time at this intensity, saving hard efforts for a few key sessions a week.