How I measure HR and HRV

Elsewhere I explain how I use my heart rate (HR) to manage my chronic disease. In this post, I will describe my equipment, which also allows me to monitor my heart-rate variability (HRV). In short, I pair a Garmin Vivoactive 3 smartwatch to a Wahoo Tickr Fit armband; the watch measures HRV well but does a poor job with HR during low-level activity—which is about all I do.

Here are the details, including reasons for not choosing competing products:

Vivoactive 3

The in-depth review and comments on DC Rainmnaker, plus my frustrating experience with the inaccurate Vivosmart wristband, convinced me to get this watch. I was particularly swayed by its measurement of HRV and its ability to pair with an armband. Fitbits don’t work with these external sensors, which was a deal-breaker for me.

I believe that the Vivoactive 3’s measurement of my HR is sufficiently accurate when I remain still (e.g. asleep) and in those rare moments when my HR is consistently high. However, I’ve tested it when I’m doing low-level activities like walking, typing, standing and sitting, or making a meal, and it’s way off (20 beats per minute) for extended periods. That’s why I use an armband, too.

The Vivoactive 3 avoids such unreliability by measuring HRV only under particular conditions—basically, when my arm is still. Its measurements are consistent with variations in my health and activity, so I believe it’s sufficiently accurate to be useful. (Garmin refers to HRV as a Stress Score and to high HRV as “low stress.”) Why would people monitor their HRV? Here are articles for normals and people with ME/CFS. Among other benefits, I can tell which foods stress or quell my system.

Wahoo Tickr Fit

While most people think of chest straps as heart-rate monitors, armbands are highly accurate, too. I prefer them because they’re easier to put on and take off, they don’t exacerbate my problems breathing, and I don’t have to sweat for them to work. DC Rainmaker recommends a Scosche armband, but I had trouble with two different units. For me, the Wahoo Tickr Fit works reliably and accurately, and its battery lasts for more than a day on a charge. The Tickr Fit measures only HR—not HRV—so I have to choose which is more important according to the situation. Anyway, the Tickr Fit doesn’t store or display my HR: it needs an ANT+ or Bluetooth receiver, such as the Vivoactive 3.