December 16, 2025
This guide breaks down what MAF training is, how to calculate your heart-rate cap, how to structure workouts, and when to use (or not use) this method for running, cycling, and general endurance.
MAF training focuses on training at or below a personalized heart-rate cap to maximize aerobic development and reduce injury risk.
You can estimate your MAF heart rate with the 180-Formula, then refine it using performance trends and real-world feedback.
Best results come from consistent low-intensity volume, tracking progress with MAF tests, and adding intensity only when you’ve built a strong aerobic base.
This article explains MAF (Maximum Aerobic Function) training step by step: the science and principles behind it, how to calculate and apply the MAF heart rate, how to structure week-to-week training, how to track progress, and who benefits most. The explanations integrate exercise physiology basics, Phil Maffetone’s original framework, and modern coaching practice so you can use the method safely and effectively.
Many runners and endurance athletes train too hard on easy days, plateau, get injured, or feel constantly fatigued. MAF training offers a clear, measurable way to slow down, build a bigger aerobic engine, and improve pace at low heart rate. Understanding how to apply it helps you avoid common mistakes like running too fast, adding intensity too soon, or judging progress too quickly.
MAF stands for Maximum Aerobic Function, a method developed by Dr. Phil Maffetone. The central idea is to do most of your training at or below a specific heart rate that corresponds roughly to your aerobic threshold. At this intensity, your body primarily uses fat as fuel, produces less lactate, and recovers more easily. Over time, you aim to run, bike, or move faster at the same low heart rate. MAF is not just “running slowly”; it is a structured, heart-rate-based system for long-term aerobic development and health.
Great for
The 180-Formula is a practical way to estimate your MAF training cap: 180 minus your age, then adjusted based on health and training history. Example: a healthy 40-year-old starts at 140 bpm (180 − 40). Subtract 10 if you’re recovering from a major illness or are frequently injured or overtrained. Subtract 5 if you have minor health issues or inconsistent training. Add 5 if you’ve been training well for over two years without problems and are progressing consistently. For many people, the effective training range is MAF HR minus 10 beats (e.g., 130–140 bpm).
Great for
Once you’ve calculated your MAF heart rate using the 180-Formula, set a range from about 10 beats below that number up to the MAF cap. For example, if your MAF HR is 140 bpm, you’ll aim to keep most sessions between 130–140 bpm, never exceeding 140. Expect to slow down on hills, heat, or wind to stay under the cap. Walking during runs is normal at first. Over time, as your fitness improves, your pace at this same heart rate should increase even though the perceived effort stays low.
Great for
MAF training works best with consistent frequency and moderate volume. A common structure is 3–6 MAF sessions per week, most between 30–90 minutes, depending on your current level. Beginners might start with 20–40 minutes of MAF walking/jogging several times per week. More advanced athletes may build to multiple 60–90-minute sessions and a longer MAF session on the weekend. The goal: more total time at or below the MAF heart rate, not occasional heroic long sessions that are hard to recover from.
Great for
A MAF test is a simple field assessment you repeat regularly to track aerobic progress. Choose a standard route or treadmill: for example, 3–5 miles or 30–60 minutes. Warm up thoroughly at low intensity, then maintain your MAF heart rate throughout the test, recording your pace or distance each mile or each fixed time block. Over weeks and months, you’re looking for your pace at the same heart rate to improve. Using the same route, similar conditions, and the same warm-up is crucial for meaningful comparisons.
Great for
Most athletes benefit from repeating a MAF test every 3–4 weeks. Testing more often can introduce noise because day-to-day variables like sleep, stress, and temperature affect performance. Testing less often can make it harder to catch trends early. Log your results: date, average pace at MAF HR, splits if applicable, and subjective effort. If your times steadily improve or remain stable while volume increases, your aerobic base is likely developing well. If they slow significantly, look at sleep, stress, nutrition, and whether you’re sneaking in too much intensity.
Great for
MAF is especially helpful for people who habitually train too hard, are coming back from injury or burnout, or are new to structured endurance training. Recreational runners who always run at the same moderately hard pace often see big gains when they slow down and accumulate more low-intensity work. Masters athletes and those with higher life stress also benefit from the gentler systemic load. It’s effective across sports: running, cycling, triathlon, hiking, and even team sports players in their off-season base phase.
Great for
The biggest psychological hurdle is how slow you may need to go at first. Many people must walk hills or even large portions of their runs to stay under MAF. This can feel like “not real training,” especially if you’re used to pace-based goals or group runs that drift too fast. Progress can be slow and non-linear. Weather and terrain can make you feel like you’re going backward. Accepting that MAF is a long-term investment and focusing on trends over months, not days, is critical.
Great for
MAF works by shifting the training emphasis from pace and distance toward physiological response and recovery, which often reveals how chronically hard many athletes have been training.
The combination of a strict aerobic cap, consistent weekly volume, and regular MAF testing creates a simple feedback loop: if you respect the cap and recover well, your pace at that heart rate tends to improve steadily over time.
MAF is most powerful when integrated into a broader plan that also considers strength, mobility, lifestyle stress, and eventually a controlled amount of higher-intensity work tailored to your goals.
Frequently Asked Questions
Many people notice small improvements in 4–6 weeks, but meaningful gains in pace at the same heart rate usually show up over 2–6 months of consistent training. If your lifestyle stress is high or your base is very low, it can take longer. Focus on the trend across several MAF tests rather than expecting weekly breakthroughs.
Yes, but the method prioritizes building your aerobic base first. Once your MAF test results plateau for a month or two, you can add limited faster work such as strides, short hill sprints, or tempo intervals 1–2 times per week while keeping most of your training at or below MAF. The goal is to layer speed on top of a strong aerobic foundation.
If your calculated MAF HR feels extremely easy yet your MAF test pace is improving, it is likely appropriate. If it feels unsustainably hard or your test performance worsens over time, your MAF HR might be set too high, or life stress and recovery may be limiting you. In that case, experiment with dropping the cap by 5 beats and monitor results, and consider speaking with a coach or healthcare provider if issues persist.
Yes. The same principles apply to walking, hiking, cycling, and other steady-state endurance activities. Calculate your MAF heart rate, warm up, and then stay under your cap during your sessions. Note that heart-rate responses differ by modality: cycling HR at a given effort may be slightly lower than running, so rely on your MAF cap as a ceiling rather than trying to force your HR up to it.
A chest-strap monitor is usually more accurate and responsive, especially during running and intervals. Wrist-based optical sensors have improved, but they can lag or spike with movement. For strict MAF training, a chest strap is ideal. If you only have a wrist watch, ensure it fits snugly, use average heart rate over several seconds, and focus on staying clearly under your cap rather than chasing a precise single number.
MAF training gives you a clear, low-stress framework to build a powerful aerobic engine: calculate your heart-rate cap, keep most training under it, and track progress with regular MAF tests. If you stay patient, adjust for life stress, and only add intensity once your base is solid, you’ll often find you can go faster for less effort and with fewer injuries. Use MAF as a long-term tool, not a quick fix, and adapt it to your goals, preferences, and real-world constraints.
Track meals via photos, get adaptive workouts, and act on smart nudges personalised for your goals.
AI meal logging with photo and voice
Adaptive workouts that respond to your progress
Insights, nudges, and weekly reviews on autopilot
Your aerobic system underpins almost all endurance performance. It is responsible for using oxygen to burn fat and carbohydrates efficiently, clearing lactate, and sustaining long efforts with minimal fatigue. MAF training deliberately targets this system, avoiding the gray zone where you’re too hard to recover well but too easy to get real speed gains. By spending many weeks or months at low heart rate, you increase mitochondrial density, capillary networks, and fat-oxidation capacity, which later allows you to handle higher-intensity work with less stress and better performance.
Great for
MAF often overlaps with what many call Zone 2, but it is not identical. Zone 2 is typically defined as 60–70% of maximal heart rate or slightly below the aerobic threshold. MAF, using the 180-Formula, is a heuristic to approximate an individualized aerobic cap that accounts for age and health history rather than just percentages of max HR. Some athletes may find their MAF heart rate sits toward the upper end of Zone 2, others toward the lower end or slightly below. The key with MAF is consistency and staying under the cap, not hitting a precise physiological threshold every second.
Great for
You can include strength training, mobility, and low-impact cross-training alongside MAF. For non-endurance sessions (e.g., lifting), heart rate will naturally spike above MAF and that’s acceptable as long as overall fatigue and health are well managed. Strength 2–3 times per week works for most people: focus on compound movements, moderate loads, and good technique. On these days, you can still do short MAF sessions before or after lifting if energy allows, but don’t force it if you feel overly tired.
Great for
The MAF method recommends focusing primarily on low-intensity training until your aerobic pace plateaus (often several months). Once you see little to no improvement in your MAF test results over 1–2 months, you can add limited higher-intensity work: for example, 1–2 sessions per week of short strides, hill sprints, or tempo intervals, while keeping the bulk of your volume at or below MAF. Any intensity should be progressive, not maximal, and you should monitor that your easy-day HR and MAF test pace don’t deteriorate.
Great for
Improvement usually shows up as faster pace at the same heart rate, or maintaining pace with less perceived effort. A small slowdown in a single test isn’t automatically a red flag; check for heat, terrain, fatigue, or illness. Consistent regression across 2–3 tests, however, suggests something is off: too much stress, insufficient recovery, poor nutrition, training above MAF, or health issues. Use these data points to adjust: reduce non-essential intensity, add sleep, de-load volume slightly, or consult a professional if you suspect health problems.
Great for
MAF is not the best stand-alone approach if you have a short time frame to peak for a high-intensity event, if you’re already aerobically well-developed and need more race-specific speed, or if you simply dislike heart-rate-based training. It can be less accurate for people with very unusual heart-rate responses (e.g., certain medications, cardiac conditions) where HR doesn’t reflect effort well. In those cases, working with a coach and using perceived exertion, power, or lab testing may be better than strictly following the 180-Formula.
Great for
