Spit or Swallow? Your sports drink, that is ;)

[La]

Very interesting post by Alex Hutchinson.
http://www.runnersworld.com/drinks-hydr ... orts-drink

So what do we know about how this actually works? As Jeukendrup's review points out, there's no metabolic reason that carbohydrate ingestion should help during short bouts of exercise (e.g. an hour or less). Your body doesn't run out of carbohydrate during such short bouts, and the exercise is over before any significant amount of the extra carbohydrate you swallow is actually absorbed and oxidized. To drive this point home, Jeukendrup and colleagues did a study in 2004 where they infused glucose (or a saline placebo) directly into the veins of cyclists performing a 40-K time trial (which takes about an hour). In this case, the cyclists actually could use the extra carbohydrate, but it had no effect on performance. The muscles simply don't need it in such a short event.

Instead, it's the brain that's influenced by mouth rinsing: fMRI studies have shown that certain regions of the brain light up when you have carbohydrate in the mouth, whether it's sweet or tasteless. Artificially sweetened (but carbohydrate-free) rinses don't produce the same effect, so it's not a taste thing, and it's not consciously mediated. In the review, Jeukendrup notes that these observations are consistent with the existence of a "central governor" that regulates motor output based on signals from the muscles -- and from other places, including the mouth.

[scrumhalfgirl]

I've actually met Jeukendrup - he's an expert in the field DH did his masters research. He's an accomplished ironman - and pretty easy on the eyes too!

[Jwolf]

Even though I know I don't need the fuel for shorter distances (1-1.5 hours) I find my recovery is better if I refuel along the way. So I take Gatorade or gels so that I'm already starting my post-run recovery.

I'd also worry about my teeth with all that rinsing!

[La]

The part I found interesting and useful was how you can still get the on-course performance benefit of taking in sports drinks even if you aren't able to stomach them. That would be huge for people who struggle to get carbs in due to having a sensitive stomach. Though he does say that you can't trick the brain beyond a certain point (one you run out of glycogen, you're out).

Keep in mind, he's talking about all-out race effort, not Sunday long run effort (where post-run recovery would be more of a concern).

Another interesting point was how it had a greater effect for people who went into the test having fasted, vs those who'd had a meal 2 hours beforehand.

[MichaelMc]

I'd be cautious about trying to use the effect on a long run; you are basically trying to "fool" your body into a higher glycogen usage. This is probably fine where efforts really won't be long enough to cause a shortfall, but a problem when your body was RIGHT to ration it.

Many people object strongly to the "central governor" theory, in my opinion many objections stem from not understanding it. In the end, all it is suggesting is we take in a massive amount of information (think of all the nerves in a body), process and use a lot of it without conscious thought.

We "sense" things like how hot our core temperature is, blood sugar levels, hydration etc without knowing it, and this information affects our performance. Most people have experiences jerking a hand away from something hot before becoming aware we were getting burned: you didn't CHOOSE that reaction.

[jamix]

The Central Governor (ahem the brain) influences performance based on input it recieves from its sensors, but it's not nearly as controlling as Tim Noakes (creator of the idea) suggests; If the brain we're truly in control, then pain-killers would be much more performance enhancing then they actually are (which is a little bit)

[Jogger Barbie]

The part I found interesting and useful was how you can still get the on-course performance benefit of taking in sports drinks even if you aren't able to stomach them. That would be huge for people who struggle to get carbs in due to having a sensitive stomach. Though he does say that you can't trick the brain beyond a certain point (one you run out of glycogen, you're out).

I find it interesting as well. As a general statement, I would say that those of us with sensitive stomachs have largely trained our bodies to perform on the relatively small amount of nutrition we can consume before and/or during a race. Part of me wonders if the strategy might have the undesirable effect of the brain tricking the body into thinking it's consumed more, and then starting the cascade into all the unfortunate side effects that come with actually consuming too much.

[La]

I doubt it. If there are no actual carbs in the stomach to digest, how can your body revolt against it?

[Jwolf]

I doubt it. If there are no actual carbs in the stomach to digest, how can your body revolt against it?

Depends how much of it is a conditioned response. People throw up when they smell something bad...

[MichaelMc]

The Central Governor (ahem the brain) influences performance based on input it recieves from its sensors, but it's not nearly as controlling as Tim Noakes (creator of the idea) suggests; If the brain we're truly in control, then pain-killers would be much more performance enhancing then they actually are (which is a little bit)

You're making the assumption that pain killers block all input and/or no feedback is required. Pain is only one type of sensation.

What do YOU think controls the muscles if not the brain/central nervous system? You can still fire a totally exhausted muscle with electrostimulation, so there is nothing in the muscle itself stopping it.

[jamix]

The Central Governor (ahem the brain) influences performance based on input it recieves from its sensors, but it's not nearly as controlling as Tim Noakes (creator of the idea) suggests; If the brain we're truly in control, then pain-killers would be much more performance enhancing then they actually are (which is a little bit)

You're making the assumption that pain killers block all input and/or no feedback is required. Pain is only one type of sensation.

Point taken.

With that said, to suggest the brain controls performance is to imply that if we we're to somehow "turn-off" the warning signals, then we'd all be able to run at considerably higher outputs. I do agree that the brain has an influence, but making up some new term called a "Central Governor" seems to make things sound more complicated than it really is. Performance is still mostly influenced by VO2max, economy, and a host of environmental factors.

[MichaelMc]

The Central Governor (ahem the brain) influences performance based on input it recieves from its sensors, but it's not nearly as controlling as Tim Noakes (creator of the idea) suggests; If the brain we're truly in control, then pain-killers would be much more performance enhancing then they actually are (which is a little bit)

You're making the assumption that pain killers block all input and/or no feedback is required. Pain is only one type of sensation.

Point taken.

With that said, to suggest the brain controls performance is to imply that if we we're to somehow "turn-off" the warning signals, then we'd all be able to run at considerably higher outputs. I do agree that the brain has an influence, but making up some new term called a "Central Governor" seems to make things sound more complicated than it really is. Performance is still mostly influenced by VO2max, economy, and a host of environmental factors.

I'm sure we all agree (even Noakes) physical factors are the primary influence on performance: they form the envelope of POSSIBLE performances.

Noakes and others spent many years searching for exactly WHAT physical limitation was preventing people from going faster or longer in situations, mostly in vain. Every "limit" failed under investigation: there is quite a bit of glycogen left in the liver when blood sugar is suddenly not regulated. VO2 max was seen as a limit but testing found no lack of oxygen at the point of failure. Same is true with heat: people go slower before any physical effect is possible, and here, their performance goes up when there is no physical benefit from carbohydrate.

Trying to determine what was limiting performance (the "governor") led to a theory it was being controlled by the central nervous system: a central "governor" on our bodies holding us away from dangerous physical failure. I don't see it as complex, but that is just an opinion.

[Jogger Barbie]

I doubt it. If there are no actual carbs in the stomach to digest, how can your body revolt against it?

Depends how much of it is a conditioned response. People throw up when they smell something bad...

So much is unpredictable and not necessarily explicable. What turned Boston 2008 from a "not great race with a porta potty stop" to "porta potty purgatory" was biting into an orange slice. Just that single bite sent my entire GI system into revolt; it happened with the first taste, even before swallowing. Bizarre but true. So I'm willing to believe that my own particular system could react badly to even the illusion that it had consumed more than usual.

[ian]

Spitting sports drink can be a useful tactic in the last 20 minutes of a hard marathon, where you're running low on fuel but can't reasonably expect to process the calories before the finish line. Furthermore, between the dehydration and the exertion, there's a lesser chance of picking up a stomach cramp or side stitch by not swallowing.

[La]

I doubt it. If there are no actual carbs in the stomach to digest, how can your body revolt against it?

Depends how much of it is a conditioned response. People throw up when they smell something bad...

So much is unpredictable and not necessarily explicable. What turned Boston 2008 from a "not great race with a porta potty stop" to "porta potty purgatory" was biting into an orange slice. Just that single bite sent my entire GI system into revolt; it happened with the first taste, even before swallowing. Bizarre but true. So I'm willing to believe that my own particular system could react badly to even the illusion that it had consumed more than usual.

You're equating stomach revolt with over-consumption. I think the two are mutually exclusive, even though they may coexist. It could be a small amount of something unpleasant that makes one feel sick. Or, as Jennifer suggests, the thought, sight or smell of something that sets off the reaction (even if your stomach has little to nothing in it to revolt against).

It's like me with shrimp: I was sick from it once, so I can't even bear the thought of eating it now (even though that was close to 40 years ago!). So, if you've made an association with certain things (sports drinks, gels) causing stomach upset, then perhaps just the thought of it could cause you problems.

I wonder if sucking on a candy would have a similar effect as swishing sports drink. And if it did, perhaps sucking on a hard candy in a flavour you don't associate with running (or past stomach issues) would work.

[jamix]

Noakes and others spent many years searching for exactly WHAT physical limitation was preventing people from going faster or longer in situations, mostly in vain. Every "limit" failed under investigation :there is quite a bit of glycogen left in the liver when blood sugar is suddenly not regulated. VO2 max was seen as a limit but testing found no lack of oxygen at the point of failure. Same is true with heat: people go slower before any physical effect is possible, and here, their performance goes up when there is no physical benefit from carbohydrate.

Your description is more elogent/better than Noakes describes it in his 900pg book "Lore of running" (as far as I can remember). Not disagreeing, but it'd be more acurrate to say "Every other variable appoached its limit before failure".

I think we both agree with one another to some extent, but assuming Noak's theory provokes some obvious questions. Where we might disagree on, is whether or not "some higher" threshold could be maintained if the "Central Governor" (CG) were somehow disabled?? Could it be 1% higher, 2% or 10%????

Another obvious question, is how can we compare two different individuals CG in a laboratory? Can the CG in one individual be more limiting to performance than in another?? If the CG cannot be compared/measured in a laboratory, then Noakes will have come up with an interesting idea which will be useless for Excercise Science!

Trying to determine what was limiting performance (the "governor") led to a theory it was being controlled by the central nervous system: a central "governor" on our bodies holding us away from dangerous physical failure. I don't see it as complex, but that is just an opinion.

It sounds complicated. I understand the concept now and clearly you do too, but it sounded like some weird Freud-ian idea at first. But its more than that too. The CG has yet to be defined using some kind of metric / unit (ex "L/kg/min" is the unit defined for VO2) as far as I know. You cannot compare two different individuals CG in a laboratory either. It's just some concept right now that has yet to be described in a more concise language as far as I know.

[Jwolf]

Essentially "central governor" theory be summarized simply by saying that our brain slows us down earlier than the measurable factors would indicate (that is, things like VO2max or available fuel aren't the absolute limiters people sometimes think they are). There are no "units" to measure it. We can overcome the limits with training- and the training methods aren't really any different than what has been traditionally done (speed work, what's normally called "threshold work", etc).

[La]

Also, it's important not to confuse/equate the "brain" with the "mind." They are two different things. The central governor (part of the brain and central nervous system) will shut you down regardless of what you mind is telling you.

[Dstew]

Also, it's important not to confuse/equate the "brain" with the "mind." They are two different things. The central governor (part of the brain and central nervous system) will shut you down regardless of what you mind is telling you.

And hence the conclusions of the research. The mind and even the body might say that it does not need carbs but the brain might be thinking to be on the safe side, we should conserve something in case the idiot decides to add on another half hour of hills like I did this weekend. It is also why almost everyone slows down in the second half of the marathon. Your body might like the pace, the mind might like the pace and the brain is saying, we should slow down to conserve fuel or to prevent more damage. At the half way mark, the brain is made aware it has to go an equal distance more and so will make decisions we are not aware of.

So in the case cited, if the brain thinks it is getting carbs, it will not engage the safety value. And mind and body do not need the carbs in any event and so performance is not affected.

Another point to consider is that everyone's safety value or central governor is set at a different level. Start to suffer some injuries and I can guarantee that the body is shut down much sooner than it would otherwise do so. And from personal experience, it will also be that much more difficult to overcome. One can almost imagine the conversation that goes on.

Mind: I can go faster and I have to do so in order to reach my race goal.

Body: I think I can go that fast.

Brain: I do not think so. Last time you two said it was alright you got hurt so I am going to slow you down to make sure that does not happen again.


From my personal experience and some time back, a sub 20 minute 5 K was huge. I did everything right in training but could not break that barrier either in training or at a race. Physically I knew I could do it, my mind said I could but my central governor was holding me back as I do have a history of over doing it. In any event, I am off on a training run and go too far in order to make it back in time for dinner. I had scolded my wife about that sort of thing and so in a panic, sprinted back home and broke the 20 minute barrier. After that, I did that several times over. My mind body and soul eventually was able to overrule the central governor and so I say it is a very real thing.

[turd ferguson]

Essentially "central governor" theory be summarized simply by saying that our brain slows us down earlier than the measurable factors would indicate (that is, things like VO2max or available fuel aren't the absolute limiters people sometimes think they are). There are no "units" to measure it. We can overcome the limits with training- and the training methods aren't really any different than what has been traditionally done (speed work, what's normally called "threshold work", etc).

[citation needed] for the proposition that traditional training, speed work, etc. is effective at overcoming whatever limits the central governor places on us.

[turd ferguson]

It sounds complicated. I understand the concept now and clearly you do too, but it sounded like some weird Freud-ian idea at first. But its more than that too. The CG has yet to be defined using some kind of metric / unit (ex "L/kg/min" is the unit defined for VO2) as far as I know. You cannot compare two different individuals CG in a laboratory either. It's just some concept right now that has yet to be described in a more concise language as far as I know.

The impression I got from reading Noakes was that they were using "central governor" as a placeholder for the idea that there was something else going on that they hadn't discovered yet, something that they hadn't discovered the mechanism for yet. Giving it a scientific name like "central governor" seems to imply that we know more about what's going on than we actually do - the fact is that its one of many nervous system functions that we really don't know much about.

[Jwolf]

Essentially "central governor" theory be summarized simply by saying that our brain slows us down earlier than the measurable factors would indicate (that is, things like VO2max or available fuel aren't the absolute limiters people sometimes think they are). There are no "units" to measure it. We can overcome the limits with training- and the training methods aren't really any different than what has been traditionally done (speed work, what's normally called "threshold work", etc).

[citation needed] for the proposition that traditional training, speed work, etc. is effective at overcoming whatever limits the central governor places on us.

What I meant, and what I remember reading Noakes answer in interviews, etc. (although sorry- I can't find any primary sources right now) is that the central governor theory doesn't really mean we should train any differently than is normally done. We know that consistent training using various combinations of speed work and volume of running will make go faster. Why they make us go faster isn't always as easy to explain by the physiologic indicators usually cited like "pushing up VO2max" or "improving lactate threshold" or using physiological metrics like heart rate. They might work because of more non-measureable factors like overcoming our brain's tendency to slow us down.

Matt Fitzgerald wrote a book called "Brain Training For Runners", subtitled "A Revolutionary New Training System to Improve Endurance, Speed, Health, and Results" based on the central governor theory. But really he proposes methods that aren't any different than other training techniques. It's just a different way of thinking about it.

[MichaelMc]

There are physical limits, and to improve your performance you need to extend them. Fooling your body to continue exerting itself when you are near overheating or continuing to burn glycogen when you are low on liver glycogen could be extremely unwise (fatal, perhaps).

For this reason I'm not at all sure the Central Governor theory offers major potential for easy gains. Cooling yourself before a race, or taking in carbs even when there isn't time to hit your system might be small areas where it is safe and effective to "out-think" your body, but those aren't game-changing. In the end consistent training, nutrition and rest will be 98% of the answer and all the rest of the stuff we love to debate might contribute the balance!

[Pat Menzies]

Training in accepted manners is also no guarantee that performances will get better in a race scenario, Many people do better training and fail to improve in races.
Several well known athletes haven't seen a PB in years despite the best training and coaching available.

[Dstew]

There are physical limits, and to improve your performance you need to extend them. Fooling your body to continue exerting itself when you are near overheating or continuing to burn glycogen when you are low on liver glycogen could be extremely unwise (fatal, perhaps).

For this reason I'm not at all sure the Central Governor theory offers major potential for easy gains. Cooling yourself before a race, or taking in carbs even when there isn't time to hit your system might be small areas where it is safe and effective to "out-think" your body, but those aren't game-changing. In the end consistent training, nutrition and rest will be 98% of the answer and all the rest of the stuff we love to debate might contribute the balance!

Found a good summary:

Noakes believes that the point in the race when you think you’ve given everything you’ve got is actually a signal or response from the brain to slow down to preserve health, rather than a physiological reality. In actuality, Noakes believes you have more to give physically when this happens.

Runners experience this during almost every race they run. At mile 8 of a half marathon, goal race pace is extremely difficult and the thought of running faster, even for just a minute, seems impossible. Yet, when you get within 400 meters of the finish, you’re somehow able to summon a kick that finds you running minutes per mile faster than goal pace.

Once your brain realizes it won’t die if you pick up the pace (because the finish line is close) it opens the biological pathways to run faster.

That’s not to say that the physiological demands of a race aren’t real. Rather, the central governor theory posits that racing is a balance between: (1) physical preparation and biological systems; (2) emotional components, such as motivation and pain tolerance; (3) and self-preservation. The exact combination of these factors is what leads to how hard you’re able to push during a race.

And to your point, the central governor deals mostly with (3) self preservation. An analogy is one can rewire to go around a fuse box but is that a smart thing to do? You may get more power but at what risk?

So instead of finding a way to fool the off switch, better to move it a little further out. Tempo and hard intervals so that one's pace in a race does not feel to fast to start as that seems to be a sure way to trigger the central governor. Related, pick a pace suited to you and your training not some arbitrary goal and have a proper race plan and strategy.