Fatmax Training - The Endurance Enhancer

Want to train smarter and go for longer? Fatmax could be the key. It helps endurance athletes (especially runners and cyclists) tap into their fat metabolism, so they can keep going without burning out. In this article, we’ll break down what Fatmax really means, how it works inside your body, and how it stacks up next to FTP (that’s Functional Threshold Power — the highest power output or effort you can sustain).

We’ll show you how to bring Fatmax training into your weekly routine, along with the right gear that’s made to keep you comfortable, focused, and moving, no matter how long the road ahead.

Key takeaways at a glance:

• Fatmax training helps endurance athletes (runners, cyclists) burn a higher percentage of fat for fuel, delaying fatigue.

• Understanding and training at your Fatmax intensity can improve performance.

• Fatmax is distinct from FTP (Functional Threshold Power). But training with both Fatmax and FTP in mind can make you stronger, faster, and more resilient.

What is Fatmax?

Fatmax is the exercise intensity where your body burns the highest amount of fat (relative to carbs) for fuel. It’s not your max effort. It’s a steady, moderate zone.

• At low to moderate intensities (about 40–65% of ‘VO2 max’ aka the maximum intensity of exercise you can do), your body uses a mix of fat and carbs for energy.

• As you go beyond 70% of VO2 max, your body relies more heavily on carbs as they are quicker to break down for energy at higher intensities.

This is how the Fatmax zone looks on a graph:

Source: CyclingApps

To clarify, ‘fat oxidation’ here means something very similar to ‘burning fat’:

• Oxidation is the process of breaking down nutrients (like fat or carbs) with oxygen to produce energy.

• When we say fat oxidation, we mean the body is using fat as a fuel source, combining it with oxygen to make energy for movement.

• It’s similar to ‘burning fat’, but scientifically, it’s more about creating energy than weight loss.

Why Fatmax Matters for Endurance: Avoid the Bonk

Your body only has so much glycogen (stored carbs) on tap. Push too hard for too long, and those reserves run out — fast. That’s when fatigue hits hard. Runners call it the bonk, and cyclists know it as hitting the wall. Either way, it’s where performance flails and finishing strong becomes a battle.

Training your body to burn fat more efficiently, especially at moderate intensities, means you’re not tapping into your limited glycogen stores as quickly. Instead, you’re leaning on a more abundant, slow-burning fuel: fat. The result?

• Glycogen lasts longer

• Fatigue sets in later

• You stay stronger deeper into the session or race

This is the power of Fatmax training: it teaches your body to become more metabolically flexible, pulling from the right fuel source at the right time, so you can push the limits without crashing.

How to Work Out Your Fatmax

Here’s how to start using Fatmax in your training, starting with how it’s calculated.

Lab Testing: The Gold Standard

The best way to pinpoint your Fatmax is through lab testing. ‘Indirect calorimetry’ is a lab test where you run or ride while connected to a device that measures how much oxygen you consume and the amount of CO₂ you produce. From this data, experts can calculate when your fat oxidation peaks, and match it to your heart rate, pace, or power output. It's precise but not always accessible to all.

Field-Based Estimations

For most runners and cyclists, lab testing isn’t doable. Fortunately, there are solid ways to train in or around your Fatmax zone:

• Perceived Exertion: Aim for a pace that feels like a 6 out of 10 — steady, sustainable, but not easy

• Talk Test: You should be able to hold a conversation, but with slightly deeper breathing

• Heart Rate Zones: Fatmax typically falls around 60–75% of your max heart rate (MHR). To estimate MHR, subtract your age from 220

Fatmax vs. Functional Threshold Power (FTP)

What is FTP? 

Functional Threshold Power (FTP) is casually known as the level of intensity a cyclist can sustain for about an hour. Being familiar with your FTP helps you push yourself, while managing lactate buildup. It's a key metric for pacing and performance in races or training sessions.

How does FTP relate to Fatmax? 

Fatmax is reached much earlier than FTP in the intensity curve. Fatmax is typically around 60–75% of your FTP. It’s the sweet spot where fat oxidation peaks, and your body becomes more efficient at using fat for fuel. 

Top athletes harness both Fatmax sessions and FTP intervals:

• Working out at Fatmax helps build a strong aerobic foundation, enhances fat metabolism, and improves endurance over time

• Training at or above FTP pushes your limits, by boosting your lactate threshold, VO2 max, and top-end speed

Incorporating Fatmax into Your Training

Here’s how to start incorporating Fatmax training in your weekly routine.

Long, Slow Distance (LSD) Runs & Rides

The classic LSD session — long, steady, and low-intensity — is often right in the Fatmax zone. These efforts build your aerobic base, improve fat metabolism, and teach your body to stay efficient over time. Think 60–90 minutes (or more), at a pace where you can comfortably hold a conversation.

Targeted Fatmax Workouts

Want more structure? Try this example:

• Warm-up: 10–15 mins ‘easy’

• Main set: 45–60 mins at 60–75% of your max heart rate

• Cool-down: 10 mins ‘easy’

Runners: keep breathing relaxed and rhythmic. 

Cyclists: aim for a steady effort below threshold but above cruising.

When is Fatmax Training Most Effective?

Depending on what you’re aiming for, here’s how Fatmax makes a difference. 

Remember: it’s not just for beginners. It’s part of the toolbox for elite endurance athletes, too.

Fatmax is low-stress, high-return, and works best when combined with higher-intensity sessions and smart fueling.

Nutrition & Fat Adaptation

Some athletes experiment with fasted sessions or low-carb strategies to encourage the body to use fat to fuel their work outs. But this isn’t for everyone! Be sure to give your body enough energy and nutrients to keep going and repair and recover.

What to Wear When Fatmax Training?

Your gear shouldn’t hold you back during Fatmax training and other work outs. Long stretches of exercise at moderate intensity can cause sweating and possibly overheating. Especially if wearing the wrong gear.

That’s where GOREWEAR steps in:

• Breathable base layers that wick sweat fast, so you stay dry and comfortable over hours

• Lightweight shirts that regulate temperature during those long, steady efforts

• Designed to move naturally with your body, eliminating chafing and distractions

• Gear that stands up to the miles, whether you’re hitting the trails or roads

FAQs: Fatmax Training

Still got questions on Fatmax training and how it could help you? Discover frequently asked questions….

• What is considered a good FTP in cycling? A good FTP varies by fitness level, but a general benchmark is: untrained rider: ~2.0–2.5 watts/kg , recreational: ~2.5–3.5 watts/kg, competitive amateur: ~3.5–4.5 watts/kg, elite: 5.0+ watts/kg, for amateur cyclists, 3.0–4.0 watts/kg is considered decent.

• What is the difference between Zone 2 and FatMax? While similar, and both refer to moderate intensity training, Zone 2 means going at 60% - 70% of your max heart rate so your body uses fat as fuel. Fatmax takes this a step further and aims to put you at peak fat burn. It is often the upper end of Zone 2.

• Do you sweat in Fatmax? Although not the main indicator you’re in Fatmax, sweating is likely due to the moderate intensity and your body expelling moisture to cool you down. Opt for high quality, breathable running and cycling clothing, so you stay feeling comfortable.