Have you ever gone for a run around your neighborhood and within the first quarter to half mile you already feel like you are breathing harder and your heart rate is getting higher? If this is the case you may want to do more zone 2 cardio to improve your aerobic base. Many people think that in order to run faster and more efficiently you have to just keep pushing yourself and train often, but this might actually be doing more harm than good.
How to Find Your Max Heart Rate
Before we can define what zone 2 is for our own cardiovascular system, we must first determine what our max heart rate is. There are 3 main options for which we can use to determine our max heart rate.
Option 1 – Lab Test
The best way to accurately measure your max heart rate is through a laboratory test, also known as a V02 max test. During the test you are supervised by an exercise physiologist or a cardiologist and will run on a treadmill with increasing intensity levels until you hit a point of complete exhaustion. Having the supervision of a doctor makes this a very safe method in performing the test, and you will get access to some interesting data like max heart rate, aerobic threshold, anaerobic threshold, and lactate threshold. This is the most accurate and safest way to find out your max heart rate.
Option 2 – Field Test
Field tests are generally not recommended except for athletes with a known good aerobic function. Beginners will usually begin to slow down before they reach their full capacity. Basically they test involves warming up by running a few miles, going all out at the very end, and measuring your max heart rate.
- Warm up by running 1-3 miles, this is dependent upon your fitness level.
- Run one mile on a track at reasonable pace, but with 400 meters to go, ramp towards your maximum effort.
- Sprint the last 100 meters as fast as you can
- Look at your heart rate data from the last 400 meters; the highest number recorded will be your maximum heart rate.
Option 3 – Estimate Your Max HR
You can estimate your max heart rate by subtracting your age from 220. Keep in mind that this is only an estimation and your own individual genetics and your current physical shape can have a lot to do in determining your true max heart rate.
Example:
220 – 29 (My Age) = 191 (My Estimated Max HR)
Alternatively, you can use this calculator if you don’t like to do math: https://www.calculatorsoup.com/calculators/health/target-heart-rate-zone-calculator.php
Heart rate Zones Defined
| Heart Rate Zone | % Max Heart Rate | Manageable Training Duration | Benefit |
|---|---|---|---|
| Zone 1 | 50% – 60% | Can be sustained for several hours | Helpful for recovery after intense exercise |
| Zone 2 | 60% – 70% | 45 – 180 Minutes | Good for building your aerobic base, good for fat-burning, can sustain pace for hours |
| Zone 3 | 70% – 80% | 40 – 90 Minutes | Helpful for improving aerobic performance, can also help with performance at higher intensity levels |
| Zone 4 | 80% – 90% | 5 – 25 Minutes | Helps increase your anaerobic threshold, good for athletic performance in short-duration |
| Zone 5 | 90% – 100% | 5 – 20 Minutes | Good for speed training, develops fast-twitch muscle fiber |
Aerobic vs anaerobic training
When you train cardio, there are two systems that your body can use to generate fuel for your muscles, aerobic and anaerobic. Each have their place in training, but if your heart rate is getting higher (zones 4-5) when you are running longer distances you could be over-stressing your body and potentially increasing your risk of injury.
Aerobic
Aerobic exercise is any exercise that uses oxygen to fuel your muscles. To be specific, this means training in heart rate zones 1-3 will use oxygen. When training in this state your body can convert both fat and glycogen (stored carbohydrates) into energy. Zone 2 cardio specifically uses fat more efficiently than any other heart rate zone making it ideal for long runs and long cardio sessions. Training aerobically is especially good for recovery, as there is very little impact done to the body.
Anaerobic
Anaerobic exercise is exercise that does not use oxygen to fuel your muscles. Instead of fat, the body will break down exclusively glycogen into energy. Anaerobic exercise is done very intensely (at zones 4 and 5) and can be very taxing on the body. Training in an anaerobic state frequently can put you at higher risk for injury. One good benefit to training anaerobically is it can help improve your V02 Max, the maximum amount of oxygen someone can use during intense exercise.
The Benefits of Training Zone 2 Cardio
- Fat Burn
- Decreased Risk of Injury
- Improves Your Ability to Run Longer and At Higher Intensities (Zones, 3/4/5)
- Decreases Overall Blood Pressure
- Increases Number of Mitochondria and Mitochondrial Efficiency
- Improves Insulin Resistance
- Improved Longevity
Training zone 2 cardio does not feel intense whatsoever. In-fact, most people who train in zone 2 don’t feel like they even ran at all when they are finished, but this is what aerobic base training should feel like. Training at lower intensities for longer periods of time builds the foundation for your cardiovascular system. At first you will likely feel like you are moving at a walking pace, but if you continue to train this way over a long period of time you will get faster and faster while being able to maintain a lower heart rate. This is an absolute game changer for when you need to access higher intensity levels.
How Often Should I Train Zone 2 Cardio?
A good general rule of thumb to train with is the 80/20 rule. The 80/20 rule dictates that 80% of your runs should be done in zone 2. This is going to be great for recovery, as running in zone 2 leaves very little impact to the body and our cardiovascular system. The other 20% can be done at a “race pace” to test to see how much your anaerobic threshold has improved.
Conclusion
Zone 2 cardio is often overlooked by many athletes due to its lack of training intensity. Many people want to train at higher intensities because they feel that they are getting “a better workout” in. But in reality they are just neglecting to train their aerobic base which weakens their overall cardiovascular foundation. Although it may take a long time to build speed training in zone 2, using the 80/20 rule over a long period of time (months to years) is absolutely key to being able to run faster while maintaining a lower heart rate, and being able to burn fat as fuel instead of carbohydrates. Training frequently in zone 2 will also help you run longer at higher intensities and avoid injuries.
