Since September 2022, I’ve learned more about heart rates and pulse than I wish I needed to know.
When working with Doctor Khan in early 2023, I received a free Fitbit from Anthem and started monitoring my heart rate. The Fitbit measured my maximum heart rate at 190.
He told me that Fitbits are inaccurate during intense exercise. If I wanted to monitor my heart rate during training, I needed to procure a chest strap monitor.
The Fitbit is suitable for lower pulse measurements. It has an optical LED sensor that measures pulse by detecting the expansions in the two arteries in the wrist. Other watches with optical sensors measure pulse, but some watches are more sensitive than others.
Some heartbeats are not strong enough, or some arrhythmias will not be counted or double-counted in the pulse. The watches calculate pulse with time between readings.
A downside to using an optical sensor for intense activity is that the skin under the watch may move more than just the pulse. Sometimes, this reading will match your stride cadence. My Fitbit report of over 180 is close to my running cadence 180.
Blood pressure cuffs may also provide a pulse reading. These are more accurate than optical sensors, though still reporting pulse.
In early 2024, I purchased a Garmin chest strap heart rate monitor that uses an electrical sensor. Two pads on the back of the strap detect the electrical current produced by heartbeats. A heartbeat may not result in a pulse. For example, at times, a medical device I wore detected my atrium was beating at 400 beats per minute, though my pulse stayed around 80. My chest strap was confused and reported heartbeats around 130 when walking.
I needed to wear a Garmin watch to capture data from the chest strap. The watch has an optical sensor on the back but uses the electrical sensor in the chest strap when recording an activity.
Polar is another manufacturer of chest strap monitors. They, too, link to a wrist device. Their website was not as informative as the Garmin site. Thus, I bought Garmin. I used a Polar chest strap in the late 90s. I’m not sure if the device was electrical or audible. It was required to be close to the heart. A wrist device reported readings and provided alerts. However, there was no recording or reporting of time series data.
Over the past 18 months, I’ve worn three different medical devices designed to record heart activity. With more leads, these devices are more accurate than chest straps and report more information, including various arrhythmias. They are designed to be worn for extended periods and attached to the torso with adhesive pads.
One of these medical devices detected my 400 bpm atrium rate and 100% AFib for 14 days.
I’d love to get my hands on one of these medical devices, though they are unavailable to the general public. Cardiologists may also implant pacemakers and loops that will constantly report heart information to a monitoring company for patients with severe heart problems.
My cardiologist does not want my heart rate to exceed 85% for the next eight weeks. I’m trying to keep it under 70%.
A conservative approach to calculating maximum heart rate is 220 less age. For me, that number is 153. My resting heart rate is 63. That makes my 70% effort at 126 and 85% at 140. The formula:
((Max – Resting) * Desired Percent) + Resting
((153 – 63) * 0.7) + 63 = 126
((153 – 63) * 0.85) + 63 = 139.5
In the past, my perceived effort at 70% did not feel stressful, and I disliked using the device for training. Perhaps my lung issues increased my heart rate to a higher point, and I have become accepting of that stress.