Garmin Body Battery is a feature on Garmin devices that aims to offer insight into your energy and readiness for training. The feature is available on a number of watches from the company. But is it really a useful feature? How does it work? Allow us to explain.
How Garmin Body Battery works
According to Garmin’s website, Body Battery combines heart rate variability (HRV), stress, and activity data to calculate the user’s likely energy reserves. It uses this information to generate a number between 1-100.
Garmin Body Battery levels:
- 0-25: Low reserve energy
- 26-50: Medium reserve energy
- 51-75: High reserve energy
- 76-100: Very high reserve energy
HRV is a useful measurement of sympathetic nervous system dominance. The sympathetic nervous system is responsible for the “fight or flight” response and is associated with increased heart rate, suppressed immunity, digestion, and anxiety, among other things. Normally, when we exhale, we become slightly more parasympathetic, meaning our body slightly relaxes. This is indicated by a slight decrease in heart rate, providing us with “variability.”
If the heart rate does not change as much during exhalation — if variability is low — it suggests the body is too stressed to calm itself down. This tends to correlate with physiological arousal, illness, toxicity, psychological stress, hunger, or incomplete recovery.
Sleep data also factors into your Body Battery score. Garmin suggests the best way to recharge your battery is to get a good night’s sleep while wearing the device.
Crucially, Garmin Body Battery relies on cumulative data. If you have a very restful day, this will be viewed in light of your prior activity. This is important: one night of poor sleep does not immediately equate to low energy. However, five nights of missed sleep start to rack up.
With the Garmin Venu 2 series, the company rolled out improvements to its Body Battery algorithms based on user feedback. It’s now far more difficult to achieve a Body Battery score of 100.
At the very least, adequate recovery time is necessary to ensure the best results from training. Weight training, for example, is biphasic. While we provide the stimulus for growth in the gym, it is actually during our anabolic rest time that the muscles repair and grow. Similar processes allow for nervous system adaptations. Going harder for longer is not always the solution.
Likewise, management of the Garmin Body Battery may teach better energy management in general. It may help users adopt healthy habits. As they say: That which is measured, improves.
Finally, tools like Body Battery allow us to identify trends. If your score is consistently lower than you would like, you can begin to look for ways to improve it. Perhaps you are sensitive to that blue light from your phone before bed and this is reducing the restoration you get during sleep? Perhaps you should give up the nightcap? These are all factors you may notice when looking at your scores.
