There are specific tests that I don’t lend much credence to on a day-to-day basis, such as CRP and HRV.
Why? They are known to have a high rate of variability from one test to the next and require many measurements to get meaningful results. You don’t see your PHP or insurance companies asking for these tests.
Having said that, my own HRV measurements over an extended period of time give me a reasonable indication of where I stand.
"Measurement conditions also play a crucial role. HRV reliability tends to improve under controlled conditions such as paced breathing, as opposed to spontaneous breathing. Additionally, factors such as posture, physical activity, stress levels, and time of day can influence HRV readings, leading to variability.[1-3]
The error range for HRV measurements can be substantial. For example, the intraclass correlation coefficient (ICC) for HRV parameters can range from 0.65 to 0.88, indicating moderate to high reliability, but still allowing for considerable variability. Another study highlighted that the coefficient of variation for HRV measures can range from less than 1% to over 100%, depending on the conditions and populations studied.[1-2]
In summary, the variability in HRV measurements is influenced by random day-to-day variations, measurement conditions, and individual physiological factors. The error range can be significant, with ICC values indicating moderate to high reliability but still allowing for notable variability."
"How meaningful is the heart rate variability number in terms of general health?
Expanded question: How meaningful is the heart rate variability number in relation to general health?
Heart rate variability (HRV) is a significant marker of autonomic nervous system function and has been extensively studied in relation to general health. Lower HRV is associated with increased mortality and morbidity across various populations, including healthy individuals and those with specific health conditions. [1-3]
HRV reflects the balance between the sympathetic and parasympathetic branches of the autonomic nervous system. A higher HRV generally indicates a healthy autonomic response and better cardiovascular health, while a lower HRV is linked to higher risks of cardiovascular events, sudden cardiac death, and overall mortality.[1-2] For instance, a study from the Atherosclerosis Risk in Communities (ARIC) cohort found that low HRV was independently associated with an increased risk of sudden cardiac death.[2]
Moreover, HRV has been shown to correlate with functional status in older adults, with lower HRV being associated with a higher risk of functional decline, independent of cardiovascular disease.[4] This suggests that HRV can be a useful marker for predicting not only cardiovascular outcomes but also general health and functional capacity.
In summary, HRV is a meaningful indicator of general health, with lower HRV values being associated with higher risks of mortality, cardiovascular events, and functional decline. This makes HRV a valuable tool in both clinical and preventive health settings."
