Most of the Garmin watches come with a wrist based heart rate sensor that can give you additional perspective in your training. In the standard settings, Garmin uses a basic calculation method to determine your heart rate zones. These zones can help you see how hard you are training, but if these zones are incorrect it can also be very confusing. An unproductive training status after a great training session or a three day recovery time when you don’t feel you pushed it that hard. Why is that? I will explain the importance of setting the heart rate zones and how some of Garmin’s advanced features are connected to each other.
So, regardless of whether or not you want to use your Garmin device’s heart rate zones to enhance your training and target specific training zones, you should absolutely take some time to set your zones up. Your device has features that rely on this as it measures how much time you spend in your different heart rate zones and draws conclusions from that.
Which features are impacted by your heart rate zones?
- Training status
- Training load
- Training effect
- Recovery time
- Body battery
- Suggested workouts
Garmin’s heart rate zones
- Percentage of maximum heart rate.
- Percentage of heart rate reserve. You enter (or let Garmin provide) your maximum and resting heart rate and your zones will be calculated based on the difference between both. It is considered to be more accurate as percentage of maximum heart rate for most people.
- Percentage of lactate threshold heart rate. There are many ways to calculate this, though the only real accurate option is to get it measured in a laboratorium. Other options range from making an educated guess to using a chest strap to do a self guided test.
Training status and heart rate zones
Many Garmin owners have seen the dreaded “Unproductive” training status, or worse: detraining and overreaching. Often it shows up at unexpected times, when you feel you’ve just done a great workout, but Garmin appears to disagree. Why is that? How is the training status calculated and how serious should you take it?
Understanding the Garmin training status
- Peaking. Your training load is down and your VO2 Max went up. You are becoming fitter, while you’ve reduced your training load. A training plan is coming to an end with a taper and you are ready for race day. Ideally.
- Productive. Your training load is up or unchanged and VO2 Max increased.
- Maintaining: Your training load is unchanged or slightly down and your VO2 Max is unchanged. You are maintaining your current fitness level, you’ll likely need to increase your training load to see further improvement.
- Recovery. Your training load is down and your VO2 Max is unchanged. Your body is recovering from a higher training load, these recovery periods are an important part of your training. You should increase your training load once your body is ready.
- Unproductive. Your training load is increased, but your VO2 Max has decreased. You might be overtraining and should add some recovery time. Stress, rest and nutrition are a factor here as well.
- Detraining. Your training load has decreased a lot and your VO2 Max has decreased as well. Increase your training load to see improvement.
- Overreaching. Your training load has increased a lot, but your VO2 Max decreased. You are overtraining and are losing fitness because of it. Lower your training load to recover.
- No Status. There is not enough data available to determine your average weekly training load or your VO2 Max.
How is VO2 Max calculated?
In order to understand how your watch calculates your VO2 Max and how you should interpret this, it’s important to understand what VO2 Max is. So, to quote Garmin:
VO2 max is the maximum volume of oxygen (in milliliters) you can consume per minute per kilogram of body weight at your maximum performance. VO2 max is an indication of aerobic fitness and should increase as your level of fitness improves.
It’s not possible to exactly measure this outside a lab, so Garmin uses Firstbeat technology to make an estimation based on your age, gender, pace and heart rate. It tries to determine the most reliable data segments in your workout and excludes segments where it detects traffic lights, steep hills, etc. It also appears to be using your maximum heart rate for the calculations, so ensure that this is setup correct.
You can read the detailed white paper from Firstbeat here to find out more.
In summary, even though your heart rate zones are not used for the calculation of your VO2 Max, you still need to make sure your heart rate settings are correct to get the most accurate VO2 Max calculation.
The training load provided by Garmin watches is a measurement of your training over the last seven days. It takes duration, intensity and quantity into account. This data together comes down to a number, which will fall into a high, optimal or low range and that’s used for the calculation of the training status I mentioned earlier.
The intensity of your workout is rated based on your how much time you spend in each heart rate zone. The more time you spend in a higher heart rate zone, the more intense your workout will be rated.
What does this mean for your training status? If your heart rate zones are set too low, Garmin can determine a run that is actually an easy run for you, is a very intense workout. When your VO2 Max declines at the same time, you can easily get an unproductive or overreaching training status. Your training load increased, while your fitness declines.
Ultimately the variation in your training load is important for the determination of your training status. It compares the training load of the last seven days to the seven days before that. Small variations in your training can however have a large impact in your training load if your heart rate zones are setup incorrect and your watch thinks you are training in zone 4 instead of zone 3.
Training load focus
The most recent line of Garmin watches also divides your training load into 3 categories:
- Anaerobic: any activity done in zone 5. This will be most likely be reached through short sprint intervals.
- High aerobic: any activity done mostly in zone 3 or 4. Moderately high to high intensity activity, like a tempo run.
- Low aerobic: any activity done mostly in zone 1 or 2. These are low intensity workouts, you should still be able to hold a conversation.
The division between low and high aerobic and the anaerobic load focus is important for the suggested workouts, which I’ll explain in a few minutes.
Your watch uses your heart rate zones to determine which training effect is applicable for you workout.
The training effect is also used as part of the calculations for your recovery time and body battery, which I’ll explain next.
and firstbeat’s algorithm. The recovery time can range anywhere from 0 hours to 4 days.
Newer, more advanced running watches also update the recovery time based on your stress level, sleep quality, aditional training intensity and daily activity levels.
Your body battery tells you how much energy you still have a left and can help you to manage your day. It can also be used to analyze what is draining your energy levels.
The calculation is done based on heart rate variability, stress and activities. The higher the training effect of your activity, the more drainage you’ll see in your body battery.
The suggested workouts are a newly added feature on some of the newer, advanced watches. It gives you a suggested training based on your current training load, recovery time, sleep data and your recent workouts. If you are lacking anaerobic training and you are well rested, you’ll be given a workout to increase your anaerobic load.
Conclusion: If your heart rate zones are not setup correctly, your device can’t determine your training load focus and it won’t be able to give you the suggested workouts you actually need at a specific time.
If you want to get the most out of your Garmin watch, it is recommended that you take some time to research and setup the proper settings for your heart rate zones. This can affect all of the above mentioned features and cause confusion and even improper training.
Using a chest strap on all your runs will most likely give you more accurate results. Wrist based heart rate sensors can have more trouble identifiying sudden changes in your heart rate, for example during an interval training.