When it comes to getting the most out of your workouts, knowing the quality and impact of each training session is invaluable. Garmin’s Training Effect feature provides this insight by measuring the physiological impact of your exercise in real-time, allowing you to make immediate adjustments to your effort level based on your training goals.

What is Training Effect?

Training Effect builds over the course of your workout and is updated in real time. This means you can use it as an on-the-go resource to tailor your workout to your needs. You can push yourself harder when you are striving to improve and slow down before you wander into the overreaching range, where the results may not be what you wanted.

Garmin’s Training Effect is divided into two distinct types—Aerobic and Anaerobic—each measuring different aspects of your fitness development.

Aerobic Training Effect Explained

Aerobic Training:

  • Develops aerobic energy production
  • Utilizes fat for energy
  • Provides endurance and stamina
  • Offers prolonged performance capacity

Available on select Garmin watches, this measures the aerobic benefit of exercise, which should correlate with the fitness improvement you expect to get from it. When you crush a difficult run, you’ve likely given yourself a bigger dose of aerobic exercise and, therefore, a bigger training effect. What good is this information for you? Well, Training Effect uses your heart rate to measure the accumulated intensity of exercise on your aerobic fitness and gives you a good indication of whether you’re maintaining your current fitness level or improving it.

Aerobic Training Effect is the same as the original Training Effect feature offered on many earlier Garmin watches, except the scale has been modified slightly to account for — let’s face it — those really short or really easy activities that have no meaningful training effect. In other words, Garmin added a “0” at the bottom of the scale.

The Science Behind Aerobic Training Effect

Technically speaking, Aerobic Training Effect is the excess post-exercise oxygen consumption (EPOC) accumulated during exercise, mapped onto a 0 to 5 scale that accounts for your fitness level and training habits. Typically, as you get fitter, you need larger “doses” of exercise to continue seeing improvement.

So, while an exercise session generating an EPOC of 60 ml-O2/kg might have given you a great training benefit when you were out of shape, it might not do very much for you once you have whipped yourself into wickedly good shape. Training Effect reflects this reality by giving a higher number in the first case than in the second case.

Anaerobic Training Effect Explained

Anaerobic Training:

  • Develops anaerobic energy production
  • Includes sprinting abilities
  • Provides fatigue resistance
  • Offers maximal performance capacity

While there isn’t a specific metric tied to it, the aspect of performance most easily associated with Anaerobic Training Effect is your ability to perform and repeat sprints. The flow of a soccer game is a good point of reference here, where the activity of the game is punctuated with sudden flurries of high-intensity activity.

Your body’s most efficient method of transforming fuel into energy requires oxygen, but sometimes your demand for energy exceeds the rate at which enough oxygen is immediately available. Luckily, your body has a backup process ready and waiting. While not nearly as efficient, the anaerobic energy process can jump into action and keep you going. The downside is that it becomes depleted quickly.

The Science Behind Anaerobic Training Effect

Whereas Aerobic Training Effect ties nicely with increasing your aerobic fitness level — expressed in terms of VO2 max — things are a little more complicated with accounting for improvements on the anaerobic side of things.

By analyzing both heart rate and speed (or power, in the case of cycling), the Anaerobic Training Effect feature quantifies the anaerobic contribution to EPOC made during these periods of exertion. The higher the Anaerobic Training Effect, the greater expected benefit to your anaerobic athletic capability.

High-intensity intervals, for example, have been shown to improve several components related to your ability to perform, and Anaerobic Training Effect quantifies this for you. However, the feature goes one step further. By analyzing the type of workout you did, it can tell you more specifically how the workout helped you. For example, if it were detected that you completed several high-speed repeats, you might get an Anaerobic Training Effect of 3.5 saying, “This activity improved your anaerobic capacity and speed due to several high-speed/power repeats.”

Understanding the Training Effect Scale

Both Aerobic and Anaerobic Training Effect use the same 0-5 scale:

Score Impact What It Means
0 None No measurable impact on fitness
1 Minor Slight improvement, better for recovery
2 Maintaining Helps maintain current fitness level
3 Improving Improves fitness when repeated regularly
4 Highly Improving Significantly improves fitness
5 Overreaching Too strenuous, needs adequate recovery

Sample Training Effects by Workout Type

The following table gives you an idea of the typical Aerobic and Anaerobic Training Effects (TE) you can expect from different workout types:

Run Type Typical Aerobic TE Typical Anaerobic TE
Long, slow distance 2.0–3.0
Maintaining aerobic fitness
0
No anaerobic benefit
20-minute threshold 3.5+
Improving lactate threshold
0
No anaerobic benefit
Lactate threshold intervals 3.0+
Improving lactate threshold
0–2.0
Minor anaerobic benefit
Sprint intervals
10 x 50 meters @ 150–200% VO2 max
0–2.0
Minor aerobic benefit
2.0–3.0
Maintaining speed
Speed intervals
10 x 400 meters @ 100–105% VO2 max
2.0–4.0
Improving aerobic fitness
3.0–4.0
Improving economy and anaerobic fitness
Speed intervals
10 x 400 meters @ 110–115% VO2 max
2.0–4.0
Improving VO2 max
4.0+
Highly improving anaerobic fitness
800-meter race 2.0+
Maintaining aerobic fitness
2.5+
Maintaining anaerobic fitness
5K race 3.5+
Improving VO2 max
1.0–2.0
Minor anaerobic benefit
10K race 4.0+
Highly improving VO2 max
0.0–2.0
Minor anaerobic benefit

Note that the above TE values and phrases are illustrative examples. Your experience may differ, depending on your personal training habits. For example, if you incorporate strides or faster fartleks into your distance runs, these can add an Anaerobic Training Effect.

As with many Garmin and Firstbeat features, it may take several training sessions for the watch to learn your fitness parameters and produce the most accurate results. While the device is still learning about you, you may see uncharacteristic TE values.

How to Use Training Effect to Improve Your Fitness

To get the most out of Training Effect, consider these strategies:

  1. Establish your baseline: Track your normal workouts for a few weeks to see what Training Effect scores they generate

  2. Target specific adaptations:

    • For endurance, aim for Aerobic scores of 3-4 regularly
    • For speed development, target Anaerobic scores of 3-4 in key workouts
  3. Balance your training: Look for patterns in your weekly scores to ensure you’re not overemphasizing one energy system

  4. Avoid constant overreaching: While occasional workouts with a score of 5 can be beneficial, consistently hitting this level may lead to overtraining

  5. Recovery monitoring: Use lower Training Effect workouts (1-2) strategically between harder sessions

Compatible Garmin Devices

Training Effect is available on many mid to high-end Garmin devices, including:

  • Forerunner Series (245 and above)
  • Fenix Series (all models)
  • Epix Series
  • MARQ Collection
  • Enduro Series
  • Instinct 2 Series
  • Venu 2 Series (simplified version)

The complete dual Aerobic/Anaerobic Training Effect is generally found on the more advanced models, while some entry-level devices may only track Aerobic Training Effect.

Training Effect vs. Other Metrics

Training Effect works best when used alongside these complementary Garmin metrics:

  • Training Status: Shows if your training is productive, maintaining, or peaking
  • Recovery Time: Suggests how long to wait before your next intense workout
  • Training Load: Tracks your exercise volume over time
  • VO2 Max: Your overall aerobic fitness level

Used together, these metrics provide a comprehensive picture of your fitness and can help prevent overtraining while ensuring continued progress.


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GameraSnap is an innovative camera remote control app designed specifically for Garmin smartwatches.

Control your smartphone camera directly from your Garmin watch—perfect for workout selfies, group shots, or capturing your training achievements. Compatible with both iOS and Android, GameraSnap makes hands-free photography simple and fun.

Want to document your training journey? During those high Training Effect workouts, use GameraSnap to capture your form during intervals or that moment when you reach a new personal best. Set up your phone at key points during your workout, and trigger the camera remotely from your Garmin watch without breaking your stride or losing your focus.

Learn more about GameraSnap and get more from your Garmin watch!


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