I have been interested in heart rate variability (HRV) for many years and used to track my morning readiness with the Elite HRV app. This app is great and it gives you a good insight to how tapped/ready your central nervous system is and gives you advice on when to rest and when to be more active.
All this is great, but I feel that have problems always relating my energy levels throughout the day to what the morning readiness score is telling me. This is where Garmins Body Battery functionaly enters.
I recently got myself an entry level Garmin Forerunner 45. This is a smart watch for beggining runners. It has gotten a lot of good reviews; Mostly from people praising the good value and that you get free coaching for goals such as training for events such as marathons.
I am actually avoiding running like the plague in order to not chronicly increase my stress levels, but got interested in getting a modern smartwatch for general heart rate and hrv monitoring that could read these values continually throughout the day (without a chest strap). I got really interested when I saw that it also somehow could measure stress and had the body battery functionality, but had low expectations for these functions.
After buying the watch and using it throughout the hollidays I must say I am impressed. I don’t think this functionality should be credited to Garmin, but rather Firstbeat Analytics who appears to have created this and many other advanced tracking functionalities available for Garmin to use.
The Garmin Body Battery feels just fantastic: It is like tracking your body readiness throughout the day rather than just having one single point first thing in the morning, like you get from the Elite HRV app. I would think it is like comparing a continuous glucose monitor to a normal one – you just get more insight to how your body is working.
If you have had a good nights sleep your body battery will be nearly filled up (100%) in the morning. I find this much more close to what I feel inside compared to what for example my Sleep Cycle app is telling me in the morning. This is understandable because the Garmin Body Battery is using continually HRV-monitoring through wrist measurements rather than information from breathing or body motion. HRV is simply put a much better indicator of the state of the central nervous system.
When you put the body under stress, from excitement, stimulants, exercise, fasting, ice baths etc., your body battery is dropping from the morning score. In the evening I typically end up with 20-30% battery left. I find this analogy to a real battery amusing and keep smiling inside when comparing myself with a smartphone throughout the day.
I over normally interested in HRV and even if this functionality appears trivial to the naive user, I can tell you it is highly advanced. How could the watch calculate your battery status? Is it finding your average HRV high and low and adapting this throughout time or is it using statistics (frequency and time domain data) and other machine learning models to figure this out? How can the algo calculate how the different stressors affect the battery status? How will the algo adapt when I go from hollydays to weekdays or when I get more physically fit? There are so many questions that I am curious to get the answers to.
I have to end this blog post now as my body battery is just 16% and I have to recharge – Looking forward to upgrading the batteries in the upcoming time with biohacks I have picked up throughout the year and upgrades in my health regime.