Tuesday, June 11, 2013

Changes as an autonomic nervous system ages 11 years - The "Wild Divine" is a bit less wild.


Just after I retired from being a Univ. of Wisconsin department chair in 2001 I bought a set of finger sensors that fit on one's three middle fingers to report skin conductance and heartbeat to a PC or MAC via an A/D converter. These were part of a package with several CDs that installed a new age game on the computer that lead you through a rich environment of classical greek temples and waterfalls, attended by soothing music, that presented tasks in which you dinked with your own heart rate variability and sympathetic (arousing)/parasympathetic (calming) balance, going alternatively through periods of calm and arousal. I thought it was a hoot, and took the time to go through the "Journey to Wild Divine: passage" and "Journey to Wild Divine: Wisdom Quest."

Some of the current incarnations of these programs have moved to web browsers. Over the years a number of heavy weight new age gurus have signed on with their wares - Deepak Chopra, Dean Ornish, and Andrew Weil (Weil was in my Harvard graduating class...I'm tempted, but I won't burden you with my jaded opinion of this class of entrepreneurs, particularly Mr. Chopra.)

The main point of this post is note my experience on pulling out the finger sensors after 11 years trying the same exercises in their new presentation. What's the difference when this 71 year old tries the same manipulations of calm and arousal that the 60 year old played with with 11 years earlier? In a nutshell, I have less command over heart rate variability, which is lower, as the swings between calm and arousal have less amplitude.

And indeed, this fits with the literature on changes in the autonomic nervous system that occur on aging. If you simply do a google search for "autonomic nervous system and aging" numerous references appear that document how healthy aging is associated with lowered heart rate variability, elevated basal sympathetic nervous activity, and reduction of overall autonomic reactivity of sympathetic and parasympathetic nervous systems. Here is a very recent review, from which I pass on one figure:

Schematic of proposed features associated with the imbalance in the autonomic nervous system during aging. During aging there is a shift in the balance of the autonomic nervous system (ANS) towards the sympathetic nervous system (SNS). This may be influenced by circulating or local brain levels of angiotensin (Ang) II and leptin. The lower activity of the parasympathetic nervous system (PSNS) is proposed to result at least in part from an age-related decline in Angiotensin-(1–7). Lower Angiotensin-(1–7) and higher Ang II or leptin in the brain medulla would predispose to a decline in baroreceptor reflex sensitivity (BRS) for control of heart rate and heart rate variability (HRV), both of which are associated with aging. Moreover, impairments in BRS and HRV can contribute to target organ damage, including metabolic dysfunction, with or without an increase in blood pressure. 

If you're inclined, like Mr. Dylan Thomas, to not "go gently into that good night" you can find numerous sources (example here) on slowing these aging changes, usually by some sort of physical movement or stimulation.

8 comments:

  1. Last week I backed a Kickstarter project from Phyode called the W/Me (http://goo.gl/en1Ea), a smartwatch that uses HRV and "ANS Age" as its primary markers for assessing the user's "mental state". I couldn't find a research precedent for using ANS aging for this purpose until your post came up in a Google search. Do you think Phyode's methodology is valid?

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  2. Let me get back to you on this. I'll have a look soon.

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  3. This is a very slick presentation, and looks like a potentially interesting product...If it were not for the fact that its development appears to be limited to Android products (i.e. no iPhone App) I would probably try it out when it is sold (There are, by the way several iPhone apps that do heart rate, HRV, etc.).....BUT, there are no pointers to basic scientific references on heart rate variability, ANS age, how it can be therapeutically altered in a beneficial way, or how his device would be used to do that. The FAQ section at the end of the web page with what look like links to such items as "What is HRV?" don't link to anything!! The Phyode "Full bio and links" doesn't yield anything significant! I would be interested in seeing something a bit more substantial from the people in the flashy video presentations (all appear to be 20-somethings, by the way). I don't want to play the complete nasty guy here, because a lot of effort went into the slick videos and description, and they look plausible, but what assures us that the fund raising "Back this project" (minimum donation $1.00) is not a scam? Does the Kickstarter cloud funding site that hosts this webpage have any quality controls or review criteria?? The "report this site to Kickstarter" link takes you to a page that requires you to join or be member of kickstarter, and I'm not inclined to take that much time on this....

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  4. Actually, the current state of their phone support is iPhone-only, not Android, due to the latter's lack of an API for the BTLE stack (coming in Android 4.3).

    Kickstarter is roughly in the same stage of oversight as eBay was in the Nineties. It was initially designed to presell artists' projects, like CDs, but it's been coopted by hardware startups. I've only backed two projects myself, and my rule is to limit my funding to monies I can easily afford to lose. Kickstarter is definitely a laissez-faire marketplace that should be limited to skeptical consumers.

    I totally agree with your take on the lack of references. I backed the project primarily on the strength of the apparent ingenuity in biomedical engineering, but I'm still not sure that the research they're basing their measurements on is well established.

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  5. Thanks for the share Deric, truly great article. I am curious of your take on the emergence of Autonomic Balance testing and its uses. From reports that I have read, this form of testing is giving doctors the tools they need to devise proper and effective care paths for their patients. However, I am curious as to what you have to say about this testing.

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  6. You make what appears to be an earnest comment, but your link basically takes me to a promotion for a commercial product of which I have no knowledge. I have published your comment, but usually veto appearance of any comment that obtains a commercial link.

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  7. Sorry Deric! I had just heard of this testing and from the various reviews I read thought that it could be used for testing the nervous system of young individuals and was curious if you had heard anything about this.

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  8. Sorry I seemed to be coming down so hard on you. I should have just said I don't know about the regime. Autonomic balance is totally central to well being... I think about my own quite a bit.

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