TRAINING ZONES AND TRAINING FOCUS
Why intensity distribution matters
July 20th 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 lactate clearance and raises your second lactate threshold.
Anaerobic: Sits above your second lactate threshold. Lactate production outpaces clearance, and the body relies increasingly on carbohydrate 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 15 to 20% at anaerobic intensity and less than 5% at high aerobic. This approach builds a strong aerobic base while developing high end capacity, and its consistency makes it sustainable over longer training cycles. It also minimises what some call grey zone, high aerobic effort that accumulates fatigue faster than it drives adaptation. The trade-off is specificity: it can feel less race specific if your event relies on threshold efforts, and the biggest practical risk is that easy sessions can feel too easy, tempting athletes to push harder than intended.
Pyramidal
Most volume sits at low aerobic intensity (70 to 80%), with a smaller share at high aerobic (15 to 20%) and the least anaerobic (5 to 10%). This maintains your aerobic base while adding some top end sharpening, and it matches race demands more closely for most endurance events, which is why it is common among athletes training for 10Ks, half marathons, and triathlons. The trade-off is balance: too much high aerobic work can cause excessive fatigue without the clear benefits of true anaerobic efforts, and the pattern may not include enough hard work for peak performance in shorter events.
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. This makes it specific to time trial and tempo-based races, and it is time efficient, delivering relatively fast fitness gains that make it popular among athletes with limited training hours. Unlike Polarized and Pyramidal, which minimise what some call grey zone, Threshold deliberately lives there, working hard enough to tire you out, but not always hard enough to maximise adaptation. The trade-off shows up over time: without variation in intensity, cumulative fatigue builds, progress plateaus, and both recovery and top end development suffer.
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.
How I Use it
My Training Focus changes with the seasons. In winter, I move on an indoor bike, with two interval sessions of one to one and a half hours a week, alongside strength work and running. It's my Pyramidal phase: indoor bike intervals target the anaerobic and high aerobic zones, while running keeps some low aerobic endurance.
The other eight months look different. I barely run, still lift twice a week, but spend far more time on the bike. Between family and work, my time is limited, so Threshold training builds fitness fastest for me. It's a fine line though, that much time in the anaerobic and high aerobic zones carries real risk, which is why my weekly gravel ride with my partner is the recovery I need.
Let me be honest: it's impossible for me to follow any of these three patterns perfectly, but staying close to the one I've chosen is good enough.
Andrej Mihelič, co-founder at Gentler Stories LLC
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, 15 to 20% anaerobic, and under 5% high aerobic. It builds aerobic base and high end capacity sustainably, though it can feel less race specific for threshold-based events.
What is pyramidal training?
Pyramidal training puts most volume at low aerobic intensity (70 to 80%), less at high aerobic (15 to 20%), and least anaerobic (5 to 10%). It matches race demands for events like 10Ks and half marathons, though too much high aerobic work can cause fatigue and limit peak performance in shorter events.
What is threshold training?
Threshold training concentrates on the second lactate threshold, with roughly 40 to 50% high aerobic, 30 to 40% low aerobic, and 15 to 25% anaerobic. It is time efficient and specific to time trial and tempo races, but carries a higher risk of cumulative fatigue and plateau.
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.
