Suggestions
Add HRV (Heart Rythm Variability) to health measurements
Knowing your average HRV can tell you a lot about how your body is doing. This can be useful to track improvements, stress, rest, and if the body is fighting a virus/inflammation. For people with CFS it is used in the mornings to estimate if they are close to crashing and should rest more, or if they are doing well. They often adjust plans and schedules based on their HVR readings.