In part two of our brilliant blog series, Team GB Master’s Cyclist and British Cycling Coach Togo Keynes dives into the fundamental importance of Zone 2 training for endurance athletes.
The lead coach and co-founder of Njinga Cycling (pictured, right) cites a recent example of gains that one time-poor client enjoyed after hitting a plateau in his training.
Togo writes:
You’re not building endurance if you’re skipping this.
Many endurance athletes believe they’re training effectively, but without structured Zone 2 sessions (essentially steady-state endurance exercise where you can train and still have a conversation. Think of it as an all-day pace where you could ride for hours without getting exhausted), they often experience:
· Poor recovery
· Fitness plateaus
· Inconsistent form
The secret to long-term improvement lies in a steady, controlled training zone below threshold and tempo (Zone 3 and 4). Zone 2 is where the foundation of the aerobic engine is truly built. Get this wrong or skip this training and you’ll pay the price later. Just like building a house, you need a solid foundation to start or you’ll have structural issues later.
The Common Error: Grey-Zone Training
David Brailsford (British Cycling Performance Director) emphasised always doing the right training at the right intensity, yet many athletes still ride ‘sort of hard’.
That ‘grey-zone’ leads to fatigue, not adaptation. In many instances when coaching amateur cyclists or triathletes, I view this as junk miles.
Many endurance cyclists I train have followed polarised training plans where they train 70%-to-80% of their weekly volume at low intensity like Zone 2 and have seen incredible results.
Dr Iñigo San Millán (Performance Physiologist to elite cyclists), has quietly been doing this since 2018 with pro cyclist Tadej Pogačar, the current world champion in road cycling and defending Tour de France winner. This large foundational volume of consistent training at Zone 2 has had a dramatic impact on Pogi’s performance and been a big contributor to him winning the Tour de France and becoming a stronger, more efficient rider.
Why Zone 2 Works: the Science Explained
Training consistently in Zone 2 delivers:
· Increased mitochondrial density and function: In layman’s terms, mitochondria are the powerhouses of the cell, they produce the energy (ATP) your muscles need to keep going. I like to think of them as the firefighters in a barbecue: The more you have, the faster the charcoal lights and the longer the fire burns. In training terms, more mitochondria equals better endurance, faster recovery, and more efficient energy use, especially in Zone 2.
· Better capillarisation, improving oxygen delivery: Essentially means your body is building more tiny vessels (capillaries) that carry oxygen-rich blood straight to the working muscles. I like to think of it like building more roads to deliver fuel - the more capillaries you have, the better and faster you can get oxygen to where it’s needed. That means more endurance, less fatigue, and faster recovery.
· Enhanced fat oxidisation, conserving glycogen: meaning your body gets better at using fat for fuel, saving your limited stores of carbs (glycogen) for when you really need them, like on a climb or final push to the finish. I like to explain it like this: Your fat stores are the slow-burning logs, and your glycogen is the quick-burning firelighter. Zone 2 training teaches your body to burn logs first, so you don’t run out of fire too early.
· Lower lactate accumulation, which supports sustained efforts: Meaning you can ride harder for longer before that heavy-legged burn kicks in. Essentially, it’s like raising the ceiling on your effort, you can push more power, for longer before your muscles start to complain. Zone 2 training helps your body clear lactate more efficiently, so you’re not drowning in it as soon as the road kicks up or the pace ramps up.
Dr San Millán describes Zone 2 as ‘ the cornerstone of endurance performance, even for world-class athletes.’ Data shows elite endurance athletes spend roughly 60% to 80% of their time in Zone 2
How Zone 2 Training Gave Luke His Real Breakthrough
I want to share a real-life example of a client I’ve worked with over the last two years, who was carrying a little too much timber, had hit a plateau with his training, and was struggling to improve.
Luke (pictured right, with Togo and also below – picture courtesy of Njinga Cycling) is a successful entrepreneur, CEO and father who balanced work and family while following Njinga’s 1-1 coaching programme personalised to his weekly time commitments and busy lifestyle.
Zone 2 training was a central focus in his training plan and contributed between 60% and 100% of his weekly training, depending on what training phase he was in. We started by building a solid foundation first doing 100% zone 2 intensity only, then slowly added volume. We then lowered his zone 2 training while introducing higher-intensity structured and progressive blocks, coupled with different Zone 2 efforts and recovery blocks.
The results after two years of coaching were staggering for someone who had limited hours to train, but once he started seeing regular improvements and his body shape changed, he began to change as a person and not just as an athlete. He became stronger, more productive, and mentally more resilient. Then he started finding more time to train in Zone 2 by getting up an hour earlier before work for several mornings a week and the smart training paid off.
Below, right are Luke’s stats from his performance at this year’s ‘We Ride Flanders’ sportive, versus 2024 (left):
2025 Flanders Sportive 2024 Flanders Sportive
· 51 minutes faster than last year, finishing 135th out of 12,500 cyclists
· +37w average power, 164 to 201 watts
· +20w normalise power, 221 to 241 watts
· +2.3 kmph average speed, 24 to 26.3 kmph
· +1,043 metres more climbing this year
· 50% faster recovery
· +0.6 in race efficiency factor (EF), 1.59 to 1.65
· +0.38 w/kg in power to weight ratio
Things that are hidden in the data and harder to comprehend:
· Better Mobility: improved muscle range of motion, flexibility, and responsiveness
· Pedalling Technique: superior pedalling motion and balance of power
· Stability: stronger core resulting in better left to right leg power distribution
The only difference between this year and last year was this year was 7 km shorter due to the removal of a section of the course.
Luke says: "Zone 2 changed everything. I climbed better recovered faster and I’m finally enjoying my cycling again".
How to Kickstart your Zone 2 Training (The Smart Way)
Zone 2 training is the only effective if you do it right. Below a simple way to get started and see real progress.
Step 1: Get Your Zones Right
No need for expensive lab testing, just complete a 20-minute Functional Threshold Power (FTP) test or RAMP test using apps like Zwift. Pair it with your heart rate monitor so you’ve got both power and heart rate data.
Step 2: Calculate Your Zones
Use an online training zone calculator to work out your zones for both power and heart rate. Don’t guess as accuracy here is everything.
Step 3: Follow a Simple 8-Week Plan
Train every day for a minimum of 45 minutes in Zone 2. If you really can’t maintain 45 minutes daily, then drop to 30 minutes occasionally, but keep it consistent.
Weeks 1-4: Ride at no more than 65% FTP and try to keep your heart rate Zone 2. Small fluctuations are normal (especially during longer efforts) but the key is to stay within a reasonable range.
Focus on a steady cadence (85 to 95 RPM) and controlled breathing.
Weeks 5-8: You have two options to build progression.
· Option 1: increase duration to 50 to 60 minutes a day
· Option 2: increase intensity slightly e.g. 65% to 68% FTP
Only progress if your heart rate (HR) stays stable throughout the session.
Coach Tips:
· HR drift should ideally stay under 5bpm.
· If your HR keeps climbing into Zone 3 then 4 at Zone 2 power, ease off. You’re going too hard.
· Minimise HR drift by staying hydrated, using a fan if indoors and controlling your breathing.
· Stress, poor sleep, low carbs, and heat will all affect HR so keep an eye on this.
Note: Discipline and consistency win. Ride smarter, not harder and you build a solid aerobic engine.
Avoid These Common Mistakes When Doing Zone 2 Training
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Misunderstanding what Zone 2 actually feels like:
Just cycling easy isn’t enough - most athletes overestimate what Zone 2 would feel like and end up cycling too hard. You need to be precise so use accurate Zone 2 power and heart rate (see step 1 and 2 above). -
Over-focusing on Zone 2 and neglecting the bigger picture:
Zone 2 is crucial, but it’s not the only piece of the puzzle. A complete performance plan includes strength work, structured fuelling recovery mobility, and eventually higher intensity intervals. Don’t use Zone 2 as an excuse to avoid what you’re less confident with. -
Mixing Zone 2 with threshold or harder intervals:
If you’re spiking your power or heart rate during what’s meant to be a Zone 2 ride by powering up the hills or vice versa on the flats, you’re no longer targeting your aerobic system. You’re just adding junk stress. Keep endurance Zone 2 sessions focused, ideally indoors for greater quality, and for longer outdoor rides then choose a flat route on quiet roads. -
Not using accurate training zones:
Your Zone 2 training is only as good as the zones you’re working with. If your FTP is outdated, guessed, or not tested correctly, which I see often - then everything built on it will be flawed. Regular, accurate testing is a non-negotiable if you want to train smarter. -
Lack of consistency:
Doing one or two Zone 2 rides here and there won’t move the needle. It takes repeated, consistent effort over weeks to build aerobic efficiency. Random training delivers random results so showing up regularly is where the real gains are made.
What’s next?
You’ve built the engine, now it’s time to strengthen the chassis.
In my next blog, I’ll explain how off-bike strength and conditioning helped Njinga cyclists become stronger climbers, faster on the flats, and more resilient on race day.
Coming soon: stronger off the bike = faster on it.
Togo Keynes
Co-founder & Head Performance Coach
Njinga Cycling
www.njingacycling.com
https://www.instagram.com/njingacycling/
Images courtesy of Nginga Cycling