Of Sprinting, and Leptin Signaling Mimetics

My good friend Chris Highcock, of Conditioning Research, (and he by way of Andrew Badenoch, of Evolvify) clued me into the recent Journal of Applied Physiology article, Is sprint exercise a leptin signaling mimetic in human skeletal muscle?  

I won’t delve into the interesting details of this paper, as Chris has already done a wonderful job of that here, but I would like to add just a few of my own thoughts about these findings.

What’s more important, vis-a-vis, weight loss — diet or exercise?

I’ll get into this a bit more in a future post, but as a Physical Culture 2.0, new breed fitness educator, I am the interface between geeked-out science, empirical wisdom and a general public searching for accurate and articulate answers, to help them make sense of the never-ending, fire-hydrant-like gusher of (often times) conflicting diet and fitness “truths”.  Two big obstacles that I have to overcome in performing this function, though, are (1) that my answers are predicated upon a base understanding of a movement (Physical Culture 2.0), which itself requires the acceptance of there being no black-and-white answers — that in all instances, the notion of n=1 and “it depends” prevail, and (2) a general public which is too tired/stressed/overwhelmed with day-to-day life to undertake the due-diligence required for such an understanding; a general public who only has time for the ingestion of pat answers.  You see the conundrum here.  And I’ll get to why this matters in relation to this particular study in a moment, but for now let’s take a quick look at an extension of the above-mentioned study’s findings — the performance of fasted-state, High Intensity Interval Training.

Fasted HIIT (or, don’t let lack of scientific underpinnings spoil the empirical results)

Dan John has articulated as much in some of his prior writings, but let’s just say that you’ve followed a Paleo-like diet for 30 days (ala Robb Wolf, or Whole9), coupled that with adhering to a basic 5 x 5 weightlifting scheme and, lo-and-behold, at the end of that trial period you find yourself having dropped 30 lbs of fat and gained 5 lbs of muscle.  Now, did you lose that fat because you physically ingested fewer calories, or did that fat loss come as the result of a favorable hormonal cascade established by the diet and/or workout scheme itself?  Or what it some other combination thereof?  And hey, “everyone” knows that one cannot simultaneously lose fat and gain muscle, but your little experiment just proved the contrary.   And here’s the thing: do you really friggin’ care that you’re treading on shaky scientific ground?  Does lack of scientific confirmation negate your results?  Is the fact that you had to punch three new holes in your belt and that your shirts are now fitting tight across the shoulders (instead of across the gut) somehow now irrelevant?

I don’t bring this up so as to promote a Flat Earth Society mentality when it comes to matters of Physical Culture, but more so as to put some prospective on the weight afforded to the supporting science (or lack thereof, as the case may be) in this area of study.  In other words, empirical evidence means a hell of a lot to me.  Pondering the “whys” behind an empirically-proven methodology’s efficacy —  intellectually invigorating as it may be — ought not get in the way of actually utilizing that methodology in the real world.  I can always go back and tweak a methodology accordingly, depending upon the outcome of follow-on science.  That I cannot articulate precisely and unquestionably (as supported by science) what, at the cellular level, is precisely occurring as a consequence of HIIT training does not prevent me from utilizing this method of training or, more importantly, from reaping the benefits.  We’ve long known, in the strength and conditioning community, that performing HIIT in a fasted state just obliterates body fat even while precipitating lean muscle gain.  Of course, there was the ever-present chorus of “there’s just no relevant science to support that claim” who presumably sat this one out, waiting for scientific conformation one way or the other.  In the training of horses, though, as in the training of athletes, the proof is in the final product.  Can these methods be more finely tuned in light of prevailing science?  You bet.  Wait for the perfect answer, though, and you’ll never get under the bar or put spikes on the field.  In other words, get in the game, and don’t allow the perfect to get in the way of the good.

This sprint/leptin study is a good case-in-point to what I’m attempting to articulate in this post.  We know, empirically, that fasted HIIT works –

*note – I am extrapolating here, as this particular study only considered the performance of a single sprint on the resultant hormonal cascade.

– and now we see, presumably, one important (and no doubt interesting!) pathway in which this scenario plays out.  We also see that being fasted (at least carbohydrate fasted) is an important part of the overall equation, here (if weight loss is a mitigating factor), and so we can now tweak our methods accordingly, and rock on.

So what’s more important in weight management, diet or exercise? 

Asking a badly articulated/constructed question is worse than asking no question at all; the problem is that the person to whom the question is directed will feel an obligation to offer-up an answer, ham-strung as it may be.  Construct a question that legitimates a sound-bite answer and you’ll get exactly that (Poli-Sci/Stats 101).  You’ll also get an answer that only approximates the truth of the matter, if that.  Of what relevance is this to the sprint/leptin study?  Well, let’s consider how best to achieve a long-term fasted state to begin with, and still have the energy required to tackle a HIIT-like training session with adequate intensity.  The short answer here is that we’ll need to first establish an enzymatic and hormonal underpinning resultant of following a Paleo-like diet.   The blood-sugar roller-coaster resultant of a (for instance) Standard American Diet will throw a monkey wrench into the works from the get-go.  I see this play out all-too-frequently in real-world practice.  That far-far-away look in the middle of a HIIT throw-down?  Yeah, that’s blood-sugar crash, up close, ugly and personal, kiddos.  At the same time, though, we know that intense physical exercise potentates the expression of that same desirable enzymatic/hormonal underpinning.  So what we’re really talking about here, of course, is synergy.  Synergy is slippery, though, and not easily accounted for in a standardized-testing, sound-bite-answer world.  The masses want easily-digestible answers (especially if provided by Oz, Oprah, et al) and synergy simply doesn’t play in that house.  Sorry to disappoint, but there it is.  You can no more bust ass in the gym and on the field, eat crap and expect phenotypical perfection than you can eating as a Paleo purist while abstaining from (at least some modicum) of repeated, physical exertion.  And no, computer jockying does not count as “repeated physical exertion”.

Synergy, my friends; diet and exercise — it’s the one-two punch, and the only way I know, to attain phenotypical perfection.

Sunday’s MetCon circuit –

Being under a bit of a time crunch didn’t prevent me from sneaking this one in.  Short, sweet, and to the point.

– 10 second sprint

– 20 ft. rope climb

– 30 ft parallel bar hand-over walk

– 20 yd dual hops

– 5 muscle-ups

– 30 ft hand-over monkey bar traverse

– 7 tire flips (+ 5 extra on the last round)

wash, rinse, repeat x 3.

Trivia for the day – 26 tire flips = 51 yards (football field sideline to sideline) 🙂

In health,