FatigueM8 Friday #3 – Heart Rate Variability as an indicator of immune response

It’s FatigueM8 Friday and to kick off, here’s the photo of the week – sunrise over the Elvin yard this morning.

Sunrise over the Elvin groups’ yard 3-Apr-2020

This week I’m focusing on the heart rate variability;  with COVID-19 grabbing a majority of the headlines, there was a couple of articles that got my attention (links at the bottom of this post). There has been a couple of articles published looking at the use of changes in Heart Rate (HR) as an early indicator of a person’s immune system starting to fight an infection. In our observations of heart rate variability (HRV), we’ve seen examples of in baseline HR and HRV as a result of different physiological events and immune responses (not COVID-19 related).

This week we’ll look at two (2) trips too and from Sydney. The first trip we’ll use as the baseline (shown below), we looked at this trip previously with a fatigue lens.

During Trip 1 there was periods of high HRV (Blue & Black lines) and periods with lower HRV (middle of the graph), correlating to increased fatigue being experienced by the driver (which was me!).

The second trip (show below) to Sydney was completed with similar start times (~5am), with the return trip was in the afternoon as compared with the night time return in Trip 1.

CBR – SYD – CBR Trip 2

If we focus in on the drive to Sydney in the morning, the HRV and HR (Red lines) are similar (as shown below), starting with lower HRV and as the drive progresses the HRV increases. We think this is likely to be connected to the Circadian Rhythm, which we’ll explore in another post. The HR remained pretty constant until right at the end of the trips, which corresponds to hitting North Sydney and having to navigate traffic and find a car park (stressful times for a Canberra driver in the big smoke).

Canberra to Sydney Trip 1 (top) and Trip 2 (bottom)

The return drive from Sydney back to Canberra is where we observe some differences in the HRV and HR. It’s import to note the in Trip 1 the driving began at 5:30pm, whereas Trip 2 the driving began at 2:45pm.