ZONE 2 ISN'T EASY: WHY LOW- INTENSITY BUILD HIGH-PERFORMANCE CYCLISTS

If you’ve ever looked at a pro cyclist’s training file, one thing stands out immediately: a huge percentage of their time is spent in Zone 2.

Even at the highest levels of the sport, where athletes can push 6–7 W/kg on climbs, roughly 70–80% of training is low-intensity.

But if Zone 2 feels “easy,” why do the best riders in the world rely on it so heavily? Because Zone 2 isn’t just easy spinning. It’s the metabolic engine room where endurance, efficiency, and long-term performance are built.

In this post, we break down the science of mitochondrial adaptation, fat oxidation, FatMax, and the reason Zone 2 is the foundation of elite cycling.

What Actually Happens in Zone 2?

Zone 2 is the intensity where you can breathe through your nose, talk full sentences, and still feel like you're cruising. But under the surface, your body is doing highly valuable work:

1. You’re exercising below your aerobic threshold.
2. Your heart rate stays stable and controlled.
3. Your muscles rely heavily on fat oxidation.
4. Lactate remains low and steady (typically under 2 mmol/L).

​It’s sustainable, repeatable, and metabolically powerful.

Why Zone 2 Builds a Stronger Cyclist ​

• 1. Mitochondrial Adaptation: The Real “Fitness” You Want
• Mitochondria are your muscle cells' power plants. More mitochondria - and better-functioning ones - translate to:
  - higher aerobic power
  - more efficient energy production
  - faster recovery
• - the ability to sustain higher intensities without fatigue
• 
  
• Zone 2 training activates the PGC-1α pathway, triggering:
• ✔️ new mitochondrial growth
• ✔️ increased density
• ✔️ improved ATP production
• 
  
• This is the deep, long-term endurance that makes you strong all season; not just for a few weeks.
• 
  
• 2. Fat Oxidation and “FatMax”: Becoming a More Efficient Engine
• A key benefit of Zone 2 is improved fat metabolism.
• As your aerobic system adapts, your body learns to burn more fat at higher power outputs.
• This is where FatMax comes in.
• FatMax is the intensity where you burn the highest amount of fat per minute.
• - For untrained riders, FatMax is often very low; sometimes easy recovery effort.
• - For trained cyclists, FatMax shifts upward, meaning you can burn a high amount of fat at much higher powers.
• 
  
• The more efficient you become:
• - the less carbohydrate you burn
• - the longer your glycogen stores last
• - the stronger you remain deep into long rides, climbs, and races
• 
  
• This is why pros seem to float through long endurance days; they’re operating at very high FatMax levels developed through years of consistent Z2 work.

3. Builds Aerobic Capacity Without Unnecessary Fatigue

Zone 2 allows you to:

✔️ accumulate big volume

✔️ ride frequently

✔️ recover quickly

✔️ support higher-intensity sessions (VO2, threshold, sprints)

High return, low stress - the most sustainable way to build endurance.

4. Supports Stronger Metabolic and Hormonal Health Consistent

Zone 2 improves:

✔️ insulin sensitivity

✔️ capillary density

✔️ blood flow

✔️ cardiac output

✔️ metabolic flexibility

This makes your entire physiology more robust - not just your legs.

Why Zone 2 Feels Hard for Many Riders

Now enough science... Many amateur cyclists struggle to stay in Zone 2 simply because:

- they ride too fast on easy days

- they chase speed or Strava segments

- group rides push them into mid-Zones

- “easy” doesn’t feel like training

But pros don’t think this way. They focus on the long game. Zone 2 requires discipline - not ego.

How Much Zone 2 Should You Do?

Here is the general outline, but remember it depends on your level, goals, experience, and available training time.

A time-crunched rider will use Z2 differently than someone training 15+ hours per week.

Important note:

Zone 2 alone isn’t the fastest way to improve when you have limited time. Why? Because Z2 adaptations rely heavily on volume. If you can’t accumulate enough hours, the training stimulus is smaller. So for athletes with limited time, the focus should be on a smart mix of Z2 for durability and high-intensity efforts for maximal stimulus.

A guideline for Z2 distribution:

3–5 hours/week → 1–2 hours of Z2

Enough to maintain aerobic base without overwhelming limited time.

5–8 hours/week → 2–4 hours of Z2

Great for balancing quality + base building.

8–12 hours/week → 50–70% Z2

Ideal for steady endurance development.

12+ hours/week → majority of riding is Z2

This is the classic “pro” distribution: high volume, mostly low intensity, with structured intensity sprinkled in.

Intensity guidelines:

- Power: 55–75% of FTP

- Heart rate: 65–75% of max HR or below aerobic threshold (LT1)

Consistency and smart volume management are the keys to Z2 success.

Final Thoughts: Zone 2 Is the Training That Makes Everything Else Work

High intensity raises your ceiling.

Zone 2 raises your floor; the part of fitness you rely on all day long.

Building a huge aerobic base means:

✔️ better endurance

✔️ better fat utilization

✔️ more stable energy

✔️ stronger climbing =

✔️ faster recovery

✔️ higher power at every zone

Zone 2 isn’t easy. Zone 2 is essential; and one of the most powerful tools in cycling performance..

Matteo Cigala
Founder & Head Coach