Disclaimer: I am not a medical professional. Always seek the advice of your physician or other qualified health providers with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this or any other website.
I am not the biggest fan of my scale. It typically takes a week's worth of measurements to land on my approximate weight. On any given day, depending on my activity level, consumption, and hydration, I can see up to 5 lbs swings between daily measurements. Frankly, the real measure of progress is my jeans! I don't think I am the only one with "skinny" and "better get to work" jeans??
During the holidays and another semester of school, I hit my annual drift into excuses and laziness. Admittedly there is also a level of "I am going to enjoy the season" and travel (for those that don't know me that well it means binge-eating ice cream) mixed into that perennial end of year spike.
Its a new year!
This year, however, I discovered a new metric that made me very uneasy, maybe just short of scared. My weight hit just under 200 lbs and that was disconcerting, but to see my average resting heart rate hit a new max was one personal record (PR) I could not celebrate.
Look at the graph below. See how the impact of stress and the lack of activity impacted my average resting heart rate for a year. Given the trends, I was not keen on finding out what would happen next. I immediately made some changes and found different ways to measure my health than just relying on the scale. I found three new metrics I now monitor as measures of my health and fitness. Measures that also provide insight into my levels of stress and my recovery.
Resting Heart Rate (RHR)
My primary target metric and motivation has been to improve my resting heart rate. Your heart rate is impacted by stress and daily activity levels. Each person's RHR is unique to them, but like all metrics, it is vital that the numbers trend in a “positive” direction. The Fitbit Charge HR and the Oura track RHR. On the Oura, I am also able to track my daily Lowest RHR.
As depicted in the graph below since October of 2019 I have been on a mission to reduce my average RHR. After hitting a peak average RHR of approximately 80 bpm I am feeling much better about my health as my average RHR is now in the 50 bpm range! Compared to the graph of my weight, I find this a more motivating metrics month over month with consistent effort.
Cardio Fitness Level
If you have a Fitbit with HR capabilities, you also have access to the Cardio Fitness measurement provided in the Fitbit application on your mobile device. It has been great watching this metric improve. The Cardio Fitness level is an approximation of your VO2 Max score. As long as you wear your Fitbit, this metric is available. The metric in Fitbit provides personalized results based on your gender and age. How do you compare to an elite marathon runner Ryan Halls score of 81?
My current score is nothing to brag about, but it is a much better number than it was in November!
Want a more accurate measure of your Cardio Fitness level? Fitbit recommends pairing your device with GPS on your phone and going on a 10 minute run on flat terrain. The more often you run with the GPS, the more accurate your score. Read more about improving your Fitbit Cardio Fitness level.
If you are not a Fitbit user you can also get an approximated VO2 Max with a Polar heart rate monitor and their Polar Beat application. It takes 5 mins to get the measurement. I do not have enough measures to compare my Fitbit Score with my Polar score. The beauty of the Fitbit score is that it is an entirely passive measurement that requires no planning or additional time.
The downside of this metic with Fitbit is that the online dashboard nor the app offers any trending or historical information for this metric. If you want to track your fitness journey with this metric you will have to manually capture it.
If anyone from Fitbit happens to read this article can you please put a word into the product manager to provide trending information for the Cardio Fitness level!?!
Heart Rate Variability (HRV)
HRV is a measure that provides a direct insight into the autonomic nervous system(ANS) and its response to two competing systems in your body; the parasympathetic (rest-and-digest) and sympathetic (fight-or-flight) branches. The relationship between these systems and your ANS leads to variations beat to beat on a cellular level to your heart telling it to speed up or to slow down. Per Oura the rule of thumb is
- High HRV is associated with rest-and-digest, general fitness, and good recovery
- Low HRV is associated with fight-or-flight, stress, illness, or overtraining
This metric has completely changed the game for my fitness as it pertains to injury prevention and understanding the impact of stress, both physical and mental, on my health and well being. I check this metric daily to help me determine my level of intensity and activity for the day. My HRV measure is how I decide between low-intensity and high-intensity workout. My HRV may also be the deciding factor to take a full rest day.
HRV with Oura Ring
HRV measures on a scale that ranges between less than 20 to over 100. HRV ranges and patterns vary greatly between individuals so it is important to track the measures in relation to your personal observations.
The image below indicates a late night for me and the measurements for the HRV. As you can see my max HRV hit around 5 AM at 108 ms. The average for the night was 52 ms. At this point, an average HRV of 50 to 60 means that I am just about fully recovered.
In the graph below you can see how average daily HRV is impacted by the previous day's average Metabolic Equivalent (METs) output. METs measures the intensity of physical activity. My Oura provides METs metric. METs activity does not explain all of the variations as HRV is also influenced by everything from your mindset, stress, and age to name a few.
I love this metric. Here is an attempt to illustrate my HRV for the last few months. The green line in the graph shows my monthly average METs. The red line shows my average HRV. Notice that as soon as my activity and intensity increased, my HRV decreased significantly. Over time, however, my HRV level continues to rise in a positive correlation with my average METs score. You can not see it, but I was sore and hurting almost daily for the first few weeks. I may have been sore and hurting for the first couple of months. Now physically, my body has adjusted well, as shown by HRV, even as my average METs continues to rise.
In this graph, you can see that as my average RHR decreases my general level of health and recovery as measured by HRV is also increasing.
I am still learning about HRV and found a few more apps that can leverage my HRV data to provide more insights into my overall recovery levels and health. Read more about HRV.
I just finished the first half of my Spring semester and so far I am still trending in the right direction. The second half of the semester is already poised to be much more stressful and demanding. I will strive to protect my routine and see if the positive fitness trend holds.
A note about the METs metric. I generally do not work out with my Oura ring. Not working out in my Oura is a limitation of how well the METs metrics can capture my daily activity. The METs metric in my graphs is now much more accurate since about January. I currently use a Polar heart rate monitor to capture my fitness activity when not wearing my Oura.