TRAINING ZONES AND TRAINING FOCUS
Why Intensity Distribution Matters
July 19th 2026・by Andrej Mihelič
GENTLER 101
FITNESS
TRAINING
Not all training is equal. The intensity at which you train determines what your body adapts to, how quickly it recovers, and whether you are building fitness or quietly accumulating fatigue. Understanding your training zones is the foundation for making that distinction.
The Three Zones
Heart rate zone models vary. Some use five zones, some three. The Outsiders supports both. For Training Focus, the three zone model is used, as it is built around two clear physiological thresholds and maps directly to how training adaptations work.
Low Aerobic: Sits below your first lactate threshold (the point where blood lactate first rises above resting levels). Your body runs primarily on fat for fuel. This is the zone for long runs, steady rides, and recovery work. It builds your aerobic base and supports fat metabolism.
High Aerobic: Falls between your first and second lactate thresholds, where fat and carbohydrate share the load. Tempo runs, moderate cycling, and steady swims live here. Training in this zone improves cardiovascular efficiency and raises your second lactate threshold.
Anaerobic: Sits above your second lactate threshold. Oxygen can no longer meet demand, so the body switches to carbohydrates for quick energy. Sprinting, intervals, and high intensity efforts push into this zone. It builds power, speed, and muscular endurance.
Training across all three zones builds a complete athlete. Each serves a purpose that the others cannot replace.
Training Focus: How You Distribute the Work
How you split your time across these zones is your training focus. Most structured training follows one of three patterns.
Polarized
Roughly 75 to 85% of training sits at low aerobic intensity, with the remainder at anaerobic intensity. Almost nothing in between. This approach builds a strong aerobic base while developing high end capacity, and it keeps you out of the grey zone where effort is high enough to cause fatigue but not high enough to drive meaningful adaptation. The main risk is that easy sessions can tempt athletes to push harder than intended.
Pyramidal
Most volume sits at low intensity (70 to 80%), with a smaller share at high aerobic intensity (15 to 20%) and the least at anaerobic intensity (5 to 10%). It is common among endurance athletes and maps well to the demands of events like 10Ks, half marathons, and triathlons. The risk is accumulating too much high aerobic work, which can cause excessive fatigue without the clear adaptation benefits of true high intensity efforts.
Threshold
A large share of training concentrates at or near the second lactate threshold, the hardest pace or power you can sustain for roughly one hour, with roughly 40 to 50% in the high aerobic zone, 30 to 40% in the low aerobic zone, and 15 to 25% anaerobic. It is time efficient and delivers relatively quick fitness gains, which makes it popular among athletes with limited training hours. The downside is cumulative fatigue. Without adequate recovery, threshold heavy training leads to a plateau and limits both top end development and recovery quality. It is also the approach most associated with the grey zone trap: working hard enough to be tired, but not hard enough to maximise adaptation.
Which Approach Is Right for You
There is no single correct answer. Your training happens across three zones, Low Aerobic, High Aerobic, and Anaerobic, each tied to your lactate thresholds and each driving a different adaptation. How you distribute your time across them, Polarized, Pyramidal, or Threshold, is your training focus, and the right one depends on your goals, your event demands, and how much volume you can absorb.
What matters most is that the distribution is intentional. Training hard across all sessions without a clear pattern is the most reliable way to accumulate fatigue without the adaptation to show for it.
In The Outsiders app you can also track your heart rate and cycling power zone distribution over time, beside Training Focus.
Frequently Asked Questions
What is training intensity distribution?
Training intensity distribution is how you split your training time across the three intensity zones, Low Aerobic, High Aerobic, and Anaerobic. In The Outsiders app, this distribution pattern is called your Training Focus.
What is polarized training?
Polarized training splits roughly 75 to 85% of training at low aerobic intensity and the remainder at anaerobic intensity, with almost nothing in between. It builds a strong aerobic base while developing high end capacity and avoids the grey zone.
What is pyramidal training?
Pyramidal training puts most volume at low intensity (70 to 80%), a smaller share at high aerobic intensity (15 to 20%), and the least at anaerobic intensity (5 to 10%). It is common among endurance athletes training for events like 10Ks, half marathons, and triathlons.
What is threshold training?
Threshold training concentrates a large share of work at or near the second lactate threshold, with roughly 40 to 50% in the high aerobic zone, 30 to 40% in the low aerobic zone, and 15 to 25% anaerobic. It is time efficient but carries a higher risk of cumulative fatigue.
Which training focus is right for me?
There is no single correct answer. The right training focus depends on your goals, your event demands, and how much volume you can absorb. What matters is that the distribution is intentional rather than random.
About the author
Andrej Mihelič
A co-founder, product owner and designer at Gentler Stories LLC. With 15+ years in mobile app development, he's a seasoned athlete passionate about sustainable training. Prioritises quality over quantity and intentional design without clutter, living and breathing Gentler Streak and The Outsiders.