Perceived exertion: HR disassociation

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May 19, 2021 at 9:38 pm #54155

Thomas Peatman
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I have been training by HR for a year or so and have a tested AeT of about 160. I ran a 50k 5 weeks ago and kept my HR below 160, but close to it except on the downhills. I finished (slowly) feeling good.

I then ran my first 50 Miler (American River) and had a significant disconnect between my HR and PE. I would run a bit on the flats late in the race and feel tapped out, so I would switch to walking. BUT, my HR might have only been 140.

So, does this reflect peripheral fatigue limiting me rather than cardiovascular? Or general systemic fatigue? I hydrated well and ingested tons of sugar (GU octane drink). It peaked at 88 degrees. I don’t understand the increased PE at relatively lower HR output. Thanks!
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Posted In: General Training Discussion

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timbenz on May 20, 2021 at 7:45 pm #54186

Generally speaking, that sort of disconnect is tied to fatigue (or, less likely, a virus). How far apart were the races? How was your recovery? How was your HRV trending coming into the second event? How has it been since?

Wrt heat, it can have a dramatic effect, depending on how heat acclimated you were before the race. Numbers vary, but can cause dramatic increase in PE at lower HR.

Participant

Thomas Peatman on May 20, 2021 at 10:16 pm #54187

Tim,
thank you! The 50M was 4 weeks later, and I did feel more beat up at 30 miles into it than at the end of the 50k.
I would have thought that heat stress would have manifested as increased HR, rather than increased PE at a lower HR, but I see your point. My HRV and RHR had not fully recovered before the longer run.Since then, my RHR (normally 48-50) has been 55-65.

I also have Parkinson’s, which may throw things off.

Inactive

Anonymous on May 21, 2021 at 8:14 am #54198

@thomas-peatman: In my experience, low HR at high RPE is usually a sign of peripheral fatigue. If your legs are tired enough, they won’t be able to stress the heart and lungs enough to increase HR.

I wouldn’t put much faith (at all) in HRV. In my experience, it’s as wrong as it is right. Like most gadgetry, it’s an appealing metric that doesn’t help much.

However, your resting HR is worth paying attention to. A near-20-beat jump definitely suggests that you’re not recovered. Even better than resting HR, try using an orthostatic test.

Participant

Jon44 on July 10, 2021 at 7:13 am #55623

Scott, appreciate your articles on orthostatic test and how it compares to the HRV apps. Do you know of an app that walks you through the orthostatic test? (E.g., beeps when it’s time to stand up, collects and graphs the data over time.) Feels like it’d be easier to devote the 5 or 6 minutes a day if it wasn’t necessary to also do number crunching, plotting, etc.

Inactive

Anonymous on July 10, 2021 at 5:45 pm #55637

Good question. When I was doing a daily orthostatic test, I created a “workout” on my watch with the necessary intervals. Then my watch would beep when I needed to change position.