The Rabbit Hole of the HRV Monitor

The Rabbit Hole of the HRV Monitor

Heart Rate Variability monitors (HRVs) are a proven method of monitoring and improving your training regimen. HRV monitors measure the difference between the sympathetic and parasympathetic nervous systems, and shows you numerically how much strain and stress you're placing upon your body. Keith Norris, general manager of Efficient Exercise, recommends the use of an HRV monitor to get the most out of your training:
"Most people have a very difficult time assessing the cumulative amount of stress placed on the body (training is only one source of stress) vis-a-vis the body's readiness for intense exercise. It's common for the stereotypical type-A personality to "motor through" rough periods in one's life. For instance, consider a mother caring for a newborn, or a hunter-gatherer enduring a "dry hunting spell". And for sure an otherwise healthy human being is more than able to cope with periodic acute bouts of some pretty severe stress and bounce back just fine. In fact, I'd argue that periodic acute bouts of overstress can serve the same purpose as periods of purposeful overtraining. There is much truth to the old wives' tale that "what doesn't kill you makes you stronger". This is the basis behind pre-season football camps. The problem, of course, is when the ol' Protestant Work Ethic collides with our evolutionarily acquired limits. Acute stress can slide into chronic stress in a rather insidious fashion. A well conditioned, type-A, 80-hour/week attorney (my typical client) who's hell-bent on "endeavoring to persevere" with his 4-a-week CrossFit beat-downs -- even in the face of severe job and personal-life stress -- will, before he knows it, come face-to-face with adrenal fatigue, over-reaching symptoms, or worse -- complete disruption of the HPTA (hypothalmus, pituitary, thyroid, adrenal) axis. I have found HRV monitoring to be a great tool for folks like this. If I can get clients to back-off on days where their sympathetic-parasympathetic autonomic nervous system is clearly not up to par, but also allow them to "blow the carbon out" on days where the autonomic nervous system is ready for prime-time, I can, in short order, prove the HRV monitoring process's worth. And, if I can get people to buy-in to the long-term process, I can show them better performance results without that constant run-down feeling indicative of constantly over-doing it." -- Source, Keith Norris Email Discussion
Based on Keith's recommendation, I've been experimenting with the use of an HRV for the past three months. The results have been interesting, but they've also been confounding. While the touted training benefit has not emerged, the raw HRV data has led me down a number of interesting rabbit holes. Using the HRV Monitor to Adjust Training Intensity I purchased my HRV Monitor from Joel Jameison, and attempted to use it to alter my training intensity. After a month of gathering HRV data, I still wasn't seeing much benefit from using the HRV monitor for to adjust my training. I had been lifting weights in the gym for over 15 years, and I have a pretty good idea of what my limits are without the use of HRV data. Outside of strength training, I have been doing a lot of hiking and biking -- but nothing that really requires fine-tuned performance monitoring. In short, I didn't find the data actionable and I didn't see a method to incorporate it into my training. I asked Joel about this, and he made several suggestions on how to use the HRV data more effectively:
"Aside from having an objective gauge of the impact of non-training related stressors, which most people are very poor at accurately accounting for, it also allows you to find the optimal balance between stress and recovery and plan for which training days should have the highest loads and which ones shouldn’t. I can’t say I’ve ever seen a training program that was achieving this balance over time effectively without any objective data playing a role in the programming and management ... (Y)ou can modify the session’s volume and intensity based on what HRV is showing that day and for the previous week. Secondly, based on weekly and monthly trends, the training methods, programming, etc. can be changed based on whether or not HRV is showing you getting closer to reaching your goals, or not. HRV is not just important to look at on a given day, but also to find out longer term effects of training, diet, stress, sleep, etc."   -- Source, Joel Jamieson Email Discussion
I took Joel's suggestions to heart, and I continued using the HRV monitor. I discussed my 'HRV level' with Keith several times, in advance of training with him. I also monitored my HRV data for variables like sleep, training intensity, food choices, progress in my strength and conditioning, etc. After using the HRV data for three months, I still don't see a benefit in using the HRV for its intended purpose: to monitor and adjust training levels. When I go in to work out with Keith Norris, or work out independently, accounting for my current HRV level hasn't added anything to my workouts. My HRV levels don't correlate strongly with my body's ability to manage a hard training day, nor do they correlate strongly with other variables like stress and sleep. Whether I'm in the HRV 'green zone' or HRV 'yellow zone' seems to have little affect on my training capacity or recovery. In short, the HRV data is not actionable and I haven't been able to incorporate it usefully into my training. (In fairness, my abnormally high HRV levels may be skewing the data results of the HRV. However, that doesn't change the fact that I simply haven't been able to find a use for the HRV data in my training or recovery). If this was all that the HRV offered, then I would argue that the HRV does not justify the monetary cost and opportunity cost. However, what's fascinating about the HRV is that it lends itself to other types of data analysis. Down the Rabbit Hole with HRV Data In our discussion, Joel Jamieson suggested that there are other ways to utilize HRV data: "(P)erhaps you haven’t used it yet long enough to see, but simply looking at dietary changes, supplement changes, sleep levels, lifestyle stress, etc. by looking at changes in HRV is another very important way to use it. Without having any objective feedback as to how any of these things are affecting you, it’s often just guesswork. For example, many people have seen how including or excluding certain foods have made a big difference in their HRV. Or other people have found that certain types of relaxation/meditation, yoga, etc. play a big role in their recovery. Even still, a lot of people try out different recovery methods and figure out which ones work the best for them and which ones don’t." I haven't found this concept to be very practical, as there has been too much noise and variability in the data. Frequently, once I find a correlation between a variable and HRV levels, that correlation fails to repeat itself in subsequent testing. Here are some examples of typical stressors, and their affect on my HRV levels:
    • A hard day of weight training generally lowers my HRV levels, sometimes it has no affect, and other times it raises my HRV levels.
    • A poor night's sleep lowers my HRV levels, two nights of poor sleep dramatically lowers my HRV levels.
    • Meditation tends to lower my HRV levels, but it does so very slowly. I've noticed a trend of my HRV being 3-4 points lower at the end of my 3 months of testing than at the beginning of testing. I have spent more time focusing on meditation (cultivating mindfulness and compassion) over the past 3 months.
    • Stress generally raises my HRV levels, but it's not always a clear correlation. Larger amounts of stress consistently raise my HRV levels by 5-10 points.
Most people don't encounter these sorts of problems. Generally speaking, higher HRV levels are good and lower HRV levels are bad. However, because my HRV generally runs 20-30 points higher than it should (considering my physical conditioning), sometimes a lower HRV is 'good' and sometimes a higher HRV is 'good'. This makes the HRV data difficult to interpret. I'm not your typical HRV monitor user, however! :) For most people, the use of an HRV data to monitor a variety of lifestyle stressors represents a true rabbit hole of data analysis. There was a fascinating discussion on this topic on The Bulletproof Executive Podcast, which really opened my eyes to the possibilities of HRV data analysis. The addition of specialized software to assist you in interpreting the HRV data, as well as use the HRV data to create change in your neural pathways, appears to be a game-changer. Despite the potential of this technology, I've been hesitant to test it on myself:
    • Because my HRV data is confounding and outside the norm, I'm not sure that the analysis software will actually prove to be helpful for me. It might just confuse things further! For whatever reason, my physiology and my HRV data is fairly unique.
    • This technology is very powerful and operates on the frontiers of engineering. Some of this technology operates by electrically stimulating parts of the brain", and despite FDA approval the long-term physiological affects are unknown. Products like the Focus offer tantalizing possibilities, but I'm not sure how many times in my life that I want to be a guinea pig! :)

Instead, I've gone the route of going through a professional biofeedback trainer. I have begun training biofeedback techiques with Dr. Zimmerman, who works with Dr. Romig. Their form of biofeedback involves using electrodes to monitor your brain activity, providing you with direct feedback, while you are being trained in how to alter your thought patterns. This training creates change in your neural pathways. (This is a more directed, faster version of the neural retraining techniques that I have used on myself). If you'd like to crawl down a rabbit hole of your own, check out these videos: Dr. Romig #1 Dr. Romig #2. I can attest first-hand that neuroplasticity is an amazing, miraculous area of medicine; 'neurohacking' is how I claimed by life back from a very serious illness. I'm optimistic that this biofeedback training will help to normalize my HRV data, because it appears that my sympathetic and parasympathetic nervous systems are out of balance. According to My HRV Readings, I'm Usain Bolt. No Autographs, please. My HRV readings are consistently in the low-to-mid-90s, occasionally over 100. This generally indicates a high level of physical conditioning, on par with the world's elite athletes. However much my physical conditioning has improved in the past 2 years, I'm still pretty far from that level of physical prowess! There's clearly something else going on here.

've asked several experts to help explain what these abnormal HRV readings mean, and I haven't gotten definitive answer back from any of them. The best information I've found seems to indicate that my HRV readings are running high due to an imbalance between my parasympathetic and sympathetic nervous systems. This sort of imbalance is generally caused by overtraining, but in my case it may be due to an abundance of stress on the body from years of trauma. It may also be due to an overstressed amygdala (which is theorized as the causation of my illness). For most people, a heightened HRV reading can be a sign of overtraining. Symptoms of parasympathetic overtraining include:

"Fatigue, Depression, Decreased Performance, Achy legs at night, Inability to Reach Normal Heart Rate During Exercise, Possible craving of carbohydrates and caffeine, Overuse injuries, Normal heart rate while at rest or LOWER HR than usual, Low Blood Pressure." -- Source: Eat, Run, Sleep.
These symptoms don't match up with what I'm experiencing, and it's very unlikely that I'm overtraining myself. A more likely explanation is that rather than my parasympathetic system being overstressed, my sympathetic system is being suppressed. According to the brain retraining expert Ashok Gupta, the sympathetic nervous system is tied into the amygdala:
"The amygdala is responsible for detecting threats to the body, and initiating appropriate responses to mitigate those threats. The insula modulates sensory experiences and information about the physiological state of the body. During a particularly stressful period in someone’s life, the amygdala is on high alert responding to emotional and physical threats. If the level of alert of the amygdala is particularly high, and the person is exposed to a toxin at the same time, a conditioned trauma can occur in the amygdala in association with the insula. This conditioning occurs because when the amygdala is on high alert, it is very prone to learning new fears and sensitivities. Even if the original toxin did not present a threat to life, the amygdala will “err on the side of caution” in it hyper-anxious state, in order to protect the body. From then on, any exposure to the original chemical, or any chemical which holds a vague resemblance to the original trigger, will initiate an over-stimulation of the sympathetic nervous system by the amygdala and hypothalamus, as well as specific reactions to mitigate the threat of the toxin. This conditioning means that the whole circuit becomes hard wired, and chronic. The brain continually over-responds ... It is a mistake that the brain makes and creates an over-protective response." -- Source: Ashok Gupta, Gupta Programme.
Perhaps my sympathetic nervous system is being suppressed, through some sort of amygdala-mediated response to trauma, and has been hard-wired into my brain. Robert Sapolsky write about the interaction between the amygdala and the sympathetic nervous system:
"Remarkably, the amygdala gets sensory information before that information reaches the cortex and causes conscious awareness of the sensation— the woman’s heart races before she is even aware of the accent of the man. The amygdala gets information from the autonomic nervous system. What’s the significance of this? Suppose some ambiguous information is filtering in, and your amygdala is “deciding” whether this is a time to get anxious. ... An exciting clinical implication of this can be found in the recent work of Larry Cahill and Roger Pitman of Harvard. They report that if you block the sympathetic nervous system in someone who has just suffered a major trauma (with a drug from chapter 3 called a beta-blocker), you decrease the odds of the person developing post-traumatic stress disorder. What’s the rationale? Decrease the sympathetic signal to the amygdala, and the amygdala is less likely to decide that this is an event that should provoke wild arousal forever after. ... So an aroused amygdala activates the sympathetic nervous system and, as we saw in the previous paragraph, an aroused sympathetic nervous system increases the odds of the amygdala activating. Anxiety can feed on itself. Why does the amygdala work differently in someone who is anxious? Some amazing research in recent years shows how this might work ... (M)ajor stressors and glucocorticoids disrupt hippocampal function— the synapses aren’t able to do that long-term potentiation business, and the dendritic processes in neurons shrink. Remarkably, stress and glucocorticoids do just the opposite in the amygdala— synapses become more excitable, neurons grow more of the cables that connect the cells to each other. And if you artificially make the amygdala of a rat more excitable, the animal shows an anxiety-like disorder afterward. Joseph LeDoux of New York University, who pretty much put the amygdala on the map when it comes to anxiety, has constructed a remarkable model out of these findings. Suppose a major traumatic stressor occurs, of a sufficient magnitude to disrupt hippocampal function while enhancing amygdaloid function. At some later point, in a similar setting, you have an anxious, autonomic state, agitated and fearful, and you haven’t a clue why— this is because you never consolidated memories of the event via your hippocampus while your amygdala-mediated autonomic pathways sure as hell remember. This is a version of free-floating anxiety. -- Source: Robert Sapolsky, Why Zebras Don't Get Ulcers

So, yes, this is quite the rabbit hole of data! While my HRV monitor hasn't told me much about my training regimen, and it hasn't helped me to track variables like food and sleep, it has pointed to an important way in which my body may still be 'out of sync'. This has led me to ask some interesting questions about my sympathetic nervous system, which will be the subject of future blog posts! :)


Sapolsky, Robert M. (2004-09-15). Why Zebras Don't Get Ulcers: The Acclaimed Guide to Stress, Stress-Related Diseases, and Coping - Henry Holt and Co.. Kindle Edition. Source: Eat, Run, Sleep: Source: The Gupta Programme, Ashok Gupta, Source, Joel Jamieson quotes: email exchange with Joel Jamieson, July 19th-22nd, 2013. Website: Source, Keith Norris quote: email exchange with Keith Norris, October 6th-7th, 2013. Website:

Posted on 2013/10/28

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