Data - Correlation between HRV and RHR - CNS fatigue? Maybe not.

[Performance Based]

I have been receiving quite a few questions regarding the tracking of my metrics and training. Some questions regarding causation and correlation have come up - I find this stuff incredibly interesting and wanted to share. Rarely do we see human performance data where one factor clearly affects another.

Resting heart rate - rate while sleeping (this is the average shown, not low peaks)
HRV - Heart rate variability, variation in timing between heartbeats.

In short we want our resting heart rate as low as possible and our HRV as high as possible. A high HRV shows your ANS and more specifically your PNS has recovered and is ready to undertake additional stress. Solid link here: https://blog.mymetabolicmeals.com/hrv-guide/

Why is this interesting? All too frequently we hear my "CNS is fried" or "adrenal fatigue"; for any well trained athlete the malleability of these systems should have adapted along your fitness journey. The recovery time of especially the PNS seems to be highly elastic.

On the left side of the chart April 19-22 these were my caloric burns for the day respectively: 6,114, 5,793, 4,726, 5,306. This took my resting (sleeping) heart rate from an average of 50ish to over 70 and HRV from an average of 95 to 30ms. After a singular day off my HRV had completely recovered showing the ability to handle additional stressors.


What this means for you? I highly recommend everyone has an Oura ring or Whoop band. This products however can be on back order frequently and are cost prohibitive. If you have the ability to track your RHR while sleeping you can extrapolate your PNS/ANS aspects of your CNS and recovery there-in. With proper data you can also extrapolate - am I experiencing CNS fatigue? Or am I simply having an off day? Properly planning deloads based off of measurable data instead of "this is how I've always done it".

 

[M@NU]

I have been receiving quite a few questions regarding the tracking of my metrics and training. Some questions regarding causation and correlation have come up - I find this stuff incredibly interesting and wanted to share. Rarely do we see human performance data where one factor clearly affects another.

Resting heart rate - rate while sleeping (this is the average shown, not low peaks)
HRV - Heart rate variability, variation in timing between heartbeats.

In short we want our resting heart rate as low as possible and our HRV as high as possible. A high HRV shows your ANS and more specifically your PNS has recovered and is ready to undertake additional stress. Solid link here: https://blog.mymetabolicmeals.com/hrv-guide/

Why is this interesting? All too frequently we hear my "CNS is fried" or "adrenal fatigue"; for any well trained athlete the malleability of these systems should have adapted along your fitness journey. The recovery time of especially the PNS seems to be highly elastic.

On the left side of the chart April 19-22 these were my caloric burns for the day respectively: 6,114, 5,793, 4,726, 5,306. This took my resting (sleeping) heart rate from an average of 50ish to over 70 and HRV from an average of 95 to 30ms. After a singular day off my HRV had completely recovered showing the ability to handle additional stressors.


What this means for you? I highly recommend everyone has an Oura ring or Whoop band. This products however can be on back order frequently and are cost prohibitive. If you have the ability to track your RHR while sleeping you can extrapolate your PNS/ANS aspects of your CNS and recovery there-in. With proper data you can also extrapolate - am I experiencing CNS fatigue? Or am I simply having an off day? Properly planning deloads based off of measurable data instead of "this is how I've always done it".

This is true.
Ive made a mistake to switch my device right at the start of a new "training phase" because ive wanted more accurate measurements but in the end, it was stupid.
Ive used a MI BAND 6 to measure my resting HR (nighttime average for the days). It was always between 58-59 BPM. Then ive started my "2-a-day workouts block" and 2 days later switched to my new wristband Withings Scanwatch.
After the first day of switching to the new block my HR nighttime HR was 60, the day after too. Then ive switched to the Scanwatch and the first night it was 66, after that constantly between 64 and 65. What annoys me with the watch is that there is always atleast 1 spike to a Heart-rate that is completely absurd each night. (sometimes also daily, i compare with my pulse oxymeter then and nothing). This 1 spike is usually enough to mess the whole average (1 spike to 190 will mess the whole average). My old watch didnt show the graph in detail so im not sure if there also were irregularities.
But what you say is true. Resting HR tells alot about your "state". Just be a bit cautious not to misinterpret data: if your body fights an infection, you have a rough night, are stressed about something etc. your heart rate could also be elevated without you being in a state of overreaching.

 

[Type-IIx]

HRV does not reflect CNS fatigue (brain & spinal cord, motor neurons).

Rather, HRV, measured by variability in the interbeat interval of the heart (or by similar proxies), reflects the state of arousal of the autonomic nervous system (ANS). The primary role of the ANS is to govern cardiac activity, which is why HRV is the primary tool for measuring its status. The ANS contains three subsystems: the sympathetic nervous system (SNS), the parasympathetic nervous system (PNS), and the enteric nervous system.

The SNS is activated during exercise to facilitate exercise performance (by increasing HR & BP and mobilizing energy stores). After exercise, there is a reduction in SNS activity together with an increase in PNS activity. The rate at which the PNS reactivates is linked to the metabolic demands of the exercise (more anaerobic/higher lactate production leads to slower PNS reactivation).

Post-exercise, the primary determinant of SNS activity seems to be the presence of metabolites within the working muscles (metabolite accumulation). Associations exist between the level of blood lactate, the level of acidosis, and the level of blood deoxygenation during exercise, and the time required to produce ANS recovery.

HRV data reflecting ANS recovery is inversely related to metabolite accumulation (i.e., more metabolite accumulation in working muscles yields slower ANS recovery).

Practically, HRV data can be useful for an endurance athlete (though I would suggest that it can distract from the business of actual training/performance) - but is irrelevant for bodybuilders or strength athletes, where neuromuscular performance is essentially unaffected by changes to HRV (except perhaps between difficult sets).

 

[Performance Based]

Extremely interesting - I stand very humbled. This to be honest is very different from everything which I have heard, read, and is frankly well… different.

Are there any modalities to measure metabolite accumulation?

I notice a very strong relationship between my HRV and muscular activation - IE proper firing muscular groups and patterning during sprints.

If you could please shed some light on the ability to monitor various electrical systems I would sincerely appreciate it mate.

 

[Performance Based]

This has been the basis of quite a few of the assumptions we have been making

Heart-Rate Variability—More than Heart Beats?

Heart-rate variability (HRV) is frequently introduced as mirroring imbalances within the autonomous nerve system. Many investigations are based on the paradigm that increased sympathetic tone is associated with decreased parasympathetic tone and vice versa. But HRV is probably more than an...

www.frontiersin.org

 

[Performance Based]

Additional non peer reviewed

Heart Rate Variability | The Ultimate Guide to HRV | WHOOP

Heart rate variability (HRV): What it is, why it's a sign of fitness, factors that affect it, how to improve it and use it to train smarter.

www.whoop.com

 

[Type-IIx]

Extremely interesting - I stand very humbled. This to be honest is very different from everything which I have heard, read, and is frankly well… different.

Are there any modalities to measure metabolite accumulation?

I notice a very strong relationship between my HRV and muscular activation - IE proper firing muscular groups and patterning during sprints.

If you could please shed some light on the ability to monitor various electrical systems I would sincerely appreciate it mate.

Practically, HRV is the modality one would use to measure metabolite accumulation. What researchers use to measure Pi, H⁺, etc. in muscle cells is impracticable.