Measuring Galvanic Skin Response….say what?


Galvanic Skin Response….say what?

If you read letsrun.com and look up anything about me I’ll be branded as some science only nut who relies on too much science and forgets the “old school” way.  If you were at my coaching presentation the Distance Summit put on at Queens University, after my “science” presentation you would probably label me as some anti-science guy, or at least anti-traditional science guy.  (Plug: If you want to watch me (and other excellent presenters) ramble on for 2+ hours you can buy the DVDs here.  I get no kickback; it was just one of the best conferences I’ve been to in terms of knowledge dropped: http://store.coachrunning.com/

The point I made at the conference is that you have to know HOW to use science.  Science isn’t evil and it isn’t a cure all.  But what it can do is provide some useful insight and data if you use it correctly.  One of the other things, you may have noticed if you read this blog, is that I’m a fan of what I call resourceful science.  Which means figuring out different ways to measure practical phenomenon. 

One of the recent things I’ve been experimenting around with is something called Galvanic skin response (GSR).  To make a long story short, GSR essentially is a way to look at sympathetic nervous system response.  It’s been used primarily in research related to arousal states and in combination with other metrics in traditional lie detector tests. In this case, I’ve been using the affective Q sensor, which is essentially a watch like device that allows us to measure GSR on the go, or in real time.


So how does that relate to running?  Well, no ones for sure yet, because there hasn’t been a lot of research on GSR and running or exercise for that matter.  But if we hypothesize and speculate for a minute, several different potential uses can be thought of.  Below is some things I’m looking into and further down is some data from three workouts from Jackie Areson, who recently got 2nd at the US indoor champs is competing in the World Indoor Championships in Istanbul, Turkey.

1.  1. Arousal states to different workouts

We all know that various kinds of workouts tend to “stress” us out before hand more so than others.  Renato Canova always makes the comment that Kenyans do a much better job of not using “nervous energy” to get through each and every hard workout.   What we’ve been doing is wearing the Q sensor for the hour or so preceding the workout to get an idea of how the arousal state increases leading up to the start of the workout.
                For example in the three workouts below, you’ll see that GSR during the latter portion of the warm-up before the 7mile straight tempo is much higher than before the other two workouts.
2.   
       2. GSR during various workouts
 Another interesting thing that can be looked at is what happens during the workout. There are various patterns that can be found.  For example, during the long steady tempo, there is a rather linear very steady increase throughout.  While on the alternating tempo which was basically 600m at 5k pace alternated with 1000m steady for 4.5mi, you see a higher peak with only some  short leveling off.  This probably occurs because of the still quick “rest” period that doesn’t really allow full recovery followed by the faster “hard” periods.  Similarly, compare it to the interval workout which was much higher intensity but with recovery jogs in between that allowed you to come back down a bit.

3 3. Recovery or time course to return GSR to baseline

Lastly, another obvious thing to look at is the time course to baseline.  We can quantify how long it took for GSR to return to pre-workout baseline levels post workout and/or post cool down.  This allows us to get a rough idea of Nervous system state, and can be used to see what recovery metrics might enhance or delay this.  For example, we can look at what happens when you stretch, do general strength, hop in an ice bath, or eat food post workout and see if there is any effect on the time course of recovery.

4 4. A lot of other things! 
 Some other metrics we’re looking at are what effects GSR during recovery in between intervals (walk/jog/run/exercises).  What keeps GSR up during the in/between time of finishing the warm-up jog to the actual workout (drills vs. strides vs. stretching). What calms or excites each athlete pre-race or workout to get them to their optimal arousal state. 



Alternating tempo

Straight long tempo:

900/500/800/400/700/300

Who cares?
The point is that it’s a relatively unexplored area and its exciting to be essentially messing around with stuff to try and figure it out.  It’s at the stage of just because we can measure it, doesn’t mean it’s important.  However, the hope is that we can collect enough data with elite runners and notice patterns or trends that correlate with other variables then it might give us another objective measurement.  And if not, then hey, it’s some cool data to mess around with!

(and if all else fails, it’s still fun to see the GSR spike in real time if you intentionally stress someone or say something to make them uncomfortable...or if you don’t want to be intrusive to someone else I can only imagine the arousal response on something like a date…so many possibilities to try!...and yes I will be the ultimate science geek wearing this thing around during different situations…)


16 comments:

  1. Steve: How would GSR compare to heart rate? Sounds like they would be similar. Also, I just skimmed and didn't detect that you have a hypothesis here, which is fine. But with these hi-low measures, don't you also have to distinguish between when hi is good, and when hi is bad. I mean, the goal isn't to be low all the time, right?

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  2. Anonymous10:57 AM

    Where do I get one of these watches???

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    Replies
    1. An MIT group called Affectiva makes this. I do research involving GSR and was quoted $2000/device about 18 months ago.

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    2. Anonymous5:17 AM

      You can get them here too...

      http://acuity-intelligence.com/products/product/36-affectiva-q-sensor

      Delete
  3. This could be an incredible tool to use in conjunction with HR training once the kinks get worked out! Perhaps it could also solve issues with overtraining where resting HR is inconsistent.

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  4. Heart rate is the best noninvasive measure of sympathetic and vagus (parasympathetic) stimulation. From a quick read on this GSR, it is an instrument that detects electric current. At rest, skin conductance measurement is an indication of sympathetic nervous system, not a direct measure. The sweating of the palm or hand will give insight to "nervousness." The readings during exercise are most likely readings of sweat response and possibly increase in thermal heat released during sweating and not SNS.

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  5. Anonymous4:56 AM

    You could certainly identify anxiety issues with this. I also wonder if there is any correllation with over training or fatigue, when measured during sleep.

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  6. So um, what exactly are you measuring?

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  7. Anonymous7:59 PM

    Very interesting. Thanks-good to see your articles again

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  8. It seems like they are measuring stress levels. More stress = shorter lifespan, and other physiological problems, but I don't see how more stress is going to make you less of a runner. Although I've always heard people say to try not to get your adrenaline up at the end of runs/workouts. But who knows if that's scientifically proven or not.

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  9. Anonymous8:21 AM

    Have you thought about measuring cortisol levels to go along with the SNA estimates since cortisol is associated with mental stress?

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  10. Have you tried collecting data for new runners to see if active lifestyle affects "stress" levels and lowers them in the long run, like with, for example, resting heart rate?

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  11. Your articles are always so interesting. Thank you for continuing to share.

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  12. Amazing post and very interesting stuff you got here! I definitely learned a lot from reading through some of your earlier posts as well and decided to drop a comment on this one!

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  13. Thanks for sharing your experiences here on your blog.

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  14. Interesting piece of information here on your website. Keep up the good work and continue providing us more quality information from time to time.

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