The Aerobic Threshold (AeT) is very important to the development of a strong aerobic base. While the gold standard for measuring it would be a laboratory test, the following Aerobic Threshold outdoor test works well most of the time to determine a baseline for aerobic training. If you have access to a treadmill, consider doing an indoor variation of this test: Read the 8-step instructions for determining your AeT on a treadmill.
You’ll want to do this AeT test in a fasted state. This means no food of any kind for at least two hours before the test. Water, black coffee, and tea without milk or sweeteners are fine. Sugary sports drinks and the like will give you inaccurate results.
Aerobic Threshold Outdoor Test
An outdoor uphill hike/run Aerobic Threshold test is not as controlled as a treadmill test, but it can still set a great baseline for your AeT. For this test the most important part is keeping a steady heart rate (HR) for as long as possible. We recommend using a long, gradual hill in the range of 5%–10% grade, but if you only have a flat area you can make this work too.
You will need a heart rate monitor for this five-step outdoor AeT test.
- Make sure your heart rate monitor is working.
- Do a walking or slow running warm-up for 15min or until you break a sweat. Make sure it is low intensity.
- After this warm-up, but without stopping, begin to increase HR gradually—5bpm every 3min—while breathing through the nose only.
- When nose breathing becomes too difficult, back off just enough to a sustainable nose breathing pace for 10–15min. Note HR at this pace! This HR usually only has a 2–4bpm difference from easy breathing to unsustainable nose breathing.
- The typical HR you see in these 15min is your AeT HR and will be the guide to the top end of your aerobic zone (Zone 2) for the next 6–8 weeks.
As your aerobic system becomes more powerful, you will notice that your AeT HR and pace will both increase over time. These increases will be small increments and will continue to accumulate over many months of consistent training. In the long term, this AeT (aerobic capacity) can continue to improve for years and years with proper training. If for some reason you have spent a lot of time at high intensity while nose breathing, you may need to do a more precise lab test to determine your aerobic baseline.
If you live in a town or don’t have access to appropriate terrain, see our Indoor DIY Guide to Determining Your Aerobic Threshold for how to do a self-administered AeT test on a treadmill.