ZONE 2 TRAINING

Zone 2 is steady aerobic riding: roughly 56-75% of FTP, or 60-70% of maximum heart rate. It sits below the first lactate turn point, which means you can hold it for hours, clear lactate as fast as you produce it, and burn a high proportion of fat for fuel.

It is the least glamorous training there is and the most reliable. Almost every elite endurance programme in the world is built on a large base of exactly this intensity.

• More mitochondria. The cellular engines that turn fat and carbohydrate into usable energy multiply in response to long submaximal work.
• Better fat oxidation. You spare glycogen for when the road tips up, and you bonk far less often.
• Denser capillary beds. More oxygen delivered to and waste cleared from the working muscle.
• A bigger stroke volume. More blood per beat, which lowers heart rate at every intensity.
• Durability. The ability to still produce good power in hour four — the quality that separates riders with identical FTPs.

The classic error is letting zone 2 drift into zone 3 because it feels more virtuous. It is not: you accumulate fatigue that steals from your hard days while getting less of the specific aerobic stimulus you came for.

Ideally 90 minutes to four hours

The adaptations are driven by accumulated time, and the deepest fat-oxidation signalling happens once glycogen starts to run down. That means longer is genuinely better.

Realistically, 60-90 minutes indoors

A 75-minute steady turbo session two or three times a week absolutely builds an aerobic base. Something at this intensity, done consistently, beats a perfect four-hour ride you never actually do.

• Break the time into blocks with a marker every 15 minutes so there is always something close to aim at.
• Add short cadence variations — 10 minutes at 95rpm, 10 at 75rpm — without touching the wattage.
• Put a fan on. Overheating is what makes indoor endurance rides unbearable, not the intensity.
• Drop in 3 x 20-second seated accelerations near the end for a bit of neuromuscular work at almost no fatigue cost.
• Music, a podcast, a very rude coach — whatever gets the hour done.