Health metrics are absolutely tarnished by a lack of proper context. Unsurprisingly, it turns out that you can't reliably take a concept as broad as health and reduce it to a number. We see the same arguments over and over with body fat percentages, vo2 max estimates, BMI, lactate thresholds, resting heart rate, HRV, and more. These are all useful metrics, but it's important to consider them in the proper context tha…
This is true of many metrics and even lab results. Good doctors will counsel you and tell you that the lab results are just one metric and one input. The body acclimates to its current conditions over time, and quite often achieves homeostasis.
My grandma was living for years with an SpO2 in the 90-95% range as measured by pulse oximetry, but this was just one metric measured with one method. It doesn't mean her blood oxygen was actually repeatedly dropping, it just meant that her body wasn't particularly suited to pulse oximetry.