The Best Guide to Zone 1 & 2 Training in the Base Phase

How to Build a Strong Aerobic Foundation for Endurance Performance

The days are short, the temperature is cold and wet—it must be the Base Phase. All of the Alpha State Athletes are deep into their General Base Phase of training. Funny enough, we all look forward to this phase once we’ve recovered from our summer season of racing. But eventually, the long, slow miles begin to test even the most dedicated athletes. Only the toughest competitors layer up in their warmest winter gear and get out there. After all, as the saying goes: "There is no such thing as bad weather, only bad clothing choices."

The fact is, logging those long, steady miles in winter is essential for endurance performance. In this blog, we’ll break down why Zone 1 & 2 training is crucial in the base phase, share an easy checklist for success, and provide simple tips to stay on track.

What is Zone 1 & 2 Training?

Zone 1 (Recovery Zone):

• Your easiest effort—conversational pace.
• Typically below 81% of your threshold heart rate.
• Perfect for recovery rides and low-intensity workouts.

Zone 2 (Aerobic Endurance Zone):

• Slightly more intense but still comfortable.
• Falls between 82-89% of your threshold heart rate.
• You can still hold a conversation without gasping for air.
• Ideal for long training sessions that build endurance.

Why Is Zone 1 & 2 Training Important?

A strong base is the foundation of endurance sports like triathlon, cycling, and running. The bigger your base, the higher your performance potential. Here’s why these zones are essential:

1. Build Aerobic Capacity

• Improves fat metabolism, preserving glycogen for high-intensity efforts.
• Enhances your ability to sustain long-distance efforts efficiently.

2. Strengthen the Heart

• Increases stroke volume, meaning your heart pumps more blood per beat.
• Leads to better cardiovascular endurance and reduced fatigue.

3. Boost Endurance & Efficiency

• Increases mitochondrial density (your muscles' powerhouses).
• Improves capillary density and red blood cell count, enhancing oxygen delivery.

4. Supports Recovery

• Zone 1 training aids active recovery, improving circulation and muscle repair.
• Helps prevent overtraining, reducing the risk of injury and burnout.

The Fastest Way to Build Endurance in the Base Phase

During the Base Phase, your goal isn’t to push limits but to develop consistency and durability. Prioritising Zone 1 & 2 training helps you:

✅ Train smarter, not harder – accumulate volume without excessive fatigue.


✅ Avoid injuries – lower intensity means less stress on muscles and joints.


✅ Lay the groundwork for race season – build an aerobic engine for high-intensity efforts later.

By sticking to low-intensity, high-volume sessions, you’ll set yourself up for a strong and successful season ahead.

Next Steps: Nutrition & Training Tips for the Base Phase

In our next blog, we’ll cover an in-depth nutrition strategy for maximising your base phase training. Stay tuned for easy fuelling tips, the best hydration strategies, and a simple pre-workout checklist to optimise your endurance.

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