Can mouthwash make you faster?

Can mouthwash make you faster?

No, we aren’t talking about Listerine, Scope, or any of those other mouthwashes that are intended to give you a clean mouth, fresh breath, and make you more kissable. We are talking about the opposite of that: a sweet drink that makes your mouth sticky with sugar, and you don’t even have to drink it. How does that work? First, let’s start with a little background.


Most athletes understand that moderate to high intensity exercise is fueled primarily by carbohydrate. We have large stores of fat, but the energy from that fat cannot be released quickly enough to fuel your muscles at those higher intensities. The chemical energy in carbohydrates can be turned into mechanical energy at a much faster rate. So pedaling harder or putting one foot in front of the other with any reasonable intensity requires carbohydrates as fuel. The problem with carbohydrate is that you can only store so much of it. Once that carbohydrate done, you’ll slow to a pace that can be sustained using only fat for energy. You’ll be slow, and you probably won’t be very happy. In the 90s, researchers firmly established that supplementing with carbohydrates, usually in the form of sugary drink, improved performance. But here’s the thing: Carbohydrate supplementation improved high intensity performance even when the intensity and duration of the exercise was not enough to deplete the athlete’s stores of carbohydrate. And these improvements were real, meaningful improvements, ranging from as little as little as 2.3-11%. What does this mean in real world terms? It means that improvements in a 40K cycling time trial, or a half marathon are measured not in seconds, but minutes. So what is going on here?

A large breakthrough came in 2004, when Doctor Carter from the University of Birrmingham did something new and interesting. He bypassed the mouth. Carter and colleagues had cyclists do a 40K time trial while receiving and infusion of either saline, or a carbohydrate solution at a rate of 1g/min of carbohydrate (similar to what an athlete could drink and absorb the good old fashioned way). As you might expect, blood glucose level in the carbohydrate group went up. What might surprise you is that there was no improvement in performance. That athletes didn’t go any faster. Carter’s follow up was to have athletes do another 40K time trial. But this time they would take a mouthful of carbohydrate drink, swirl it around for 5 seconds and then spit it out. You can probably guess what happened: The athletes improved on the order of about 3%, similar to if they had actually swallowed the drink. Once again, the improvement could be measured not just in seconds, but in minutes. Several other researchers have found similar results, but not all of them have. But there does seem to be a growing body of evidence that at least in some circumstances, a carbohydrate rinse improves endurance performance. So how does it work?


“Central governor theory” suggests that one of the limiters of performance is the brain, and I’m not talking about mental toughness here. According to central governor theory, the brain is constantly taking in all sorts of information about the physiological state of the body, and then regulating muscle recruitment based on that information. The evolutionary value of this would be to reduce the likelihood of self-harm. The brain tells the body to “ease up” to keep from hurting itself. The research on carbohydrate mouthwash/rinses suggests that some sort of chemoreceptors in the mouth tell the brain “more carbohydrate is coming!” so the brain allows the muscles to keep on pumping away.

Of course not everyone agrees. A few studies have shown no effect with the carbohydrate rinse. A few of these studies may have found an effect if the sample size were larger (the larger the sample, the easier it is to find differences). Studies that included 4 hours or more of fasting before the exercise session were more likely to find a benefit. So starting with full stores of muscle and liver glycogen may blunt the effect of the rinse. It also appears that the rinse doesn’t help with efforts of about 30 minutes or less, and nobody has really looked at efforts over 70 minutes.

So how can you put this information to use in a practical way? To some extent, this research has value even if we can’t put it directly to use right now, as it gives us insight into what limits human performance. But I think we can put it to practical use. In most cases, athletes should simply swallow their carbohydrate mix rather than spit it out. But athletes that experience an upset stomach ( GI distress) may be able to get the performance benefits of carbohydrate supplementation, while avoiding the distress. Some experimentation during training may be required, and the athlete may find it best to “rinse and spit”, “spit one, swallow one”, or something along those lines. The other practical implication is for people that are training for weight loss. It would be theoretically possible to use the “rinse and spit” method to complete a more intense workout, while also minimizing calorie intake.

So next time your legs are heavy and your stomach is in knots, just try the rinse and spit.

Questions? What would you like to see me write about next? Email me:

Resources and further reading

Beelen, M., J. Berghuis, B. Bonaparte, S.B. Ballak, A.E. Jeukendrup, and L.J. van Loon (2009). Carbohydrate mouth rinsing in the fed state: Lack of enhancement of time-trial performance. Int. J. Sport Nutr. Exerc. Metab. 19:400-409.

Carter, J.M., A.E. Jeukendrup, C.H. Mann, and D.A. Jones (2004). The effect of glucose infusion on glucose kinetics during a 1-h time trial. Med. Sci. Sports Exerc. 36:1543-1550.

Carter, J.M., A.E. Jeukendrup, and D.A. Jones (2004). The effect of carbohydrate mouth rinse on 1-h cycle time trial performance. Med. Sci. Sports Exerc. 36:2107-2111.

Chambers, E.S., M.W. Bridge, and D.A. Jones (2009). Carbohydrate sensing in the human mouth: Effects on exercise performance and brain activity. J. Physiol. 587:1779-1794. Fares, E.J., and B. Kayser (2011). Carbohydrate mouth rinse effects on exercise capacity in pre- and postprandial states. J. Nutr. Metab.2011:385962.

Jeukendrup, A.E., S. Hopkins, L.F. Aragon-Vargas, and C. Hulston (2008). No effect of carbohydrate feeding on 16 km cycling time trial performance. Eur. J. Appl. Physiol. 104:831-837.

Luden ND, Saunders MJ, D’Lugos AC, et al. Carbohydrate Mouth Rinsing Enhances High Intensity Time Trial Performance Following Prolonged Cycling. Nutrients. 2016;8(9):576. doi:10.3390/nu8090576.

Noakes, T.D. (2000). Physiological models to understand exercise fatigue and the adaptations that predict or enhance athletic performance. Scand. J. Med. Sci. Sports 10:123-145.

Silva T de A e, de Souza MEDCA, de Amorim JF, Stathis CG, Leandro CG, Lima-Silva AE. Can Carbohydrate Mouth Rinse Improve Performance during Exercise? A Systematic Review. Nutrients. 2014;6(1):1-10.

Staying Hydrated at the Giro Di San Diego Granfondo

It  has been hot recently, and there is no reason to expecting anything else on the day of the big ride.    On long hot rides, it is especially important to think about hydrating properly .      Your body is about  two thirds water and  being  only 3% dehydrated can lead to as much as a  20% decrease in your performance.    We are all out there to do a long ride, but at the same time, none of us want to slow down by 20% throughout  the ride!  Most riders doing the medio fondo will be out there for well over 3 hours, and  the majority of  the granfondo riders will be pedaling more than 6.     If it is hot, and you are sweating heavily the average person loses  anywhere between 0.8 and 1.5 liters per hour.   The problem is  your stomach  can only  process  fluid at about half that rate, so you are going to be at least somewhat dehydrated  by the end of the ride.   The  key  is  to finish the ride as hydrated as possible and then rehydrate properly afterward.     It sounds simple, but what is the best way to do that?


You've probably heard the basic advice  “ drink early and drink often” but what exactly does that mean?    At its most basic level, this means that when you are in it for a long haul, start drinking before you are thirsty.     You should try to drink all or most of a small water bottle or the better part of a big one each hour.    This means you’ll need to start drinking shortly after you leave the start line and it also means you’ll need to  take the time to fill up at the rests stops along the way.    Follow that “one small bottle per  hour” rule and you’ll  stay as hydrated  and as strong as possible though the ride.

Every bit as important as how much you drink is what you put in your bottle.   For rides under 2 hours, plain old water will be just fine.    But for   long days in the saddle, a carbohydrate/electrolyte drink is essential.   The carbohydrates  are important because they are the primary fuel used during exercise.   Without a carbohydrate beverage you’ll run out of energy and have trouble keeping up your pace.  But even more important than the carbohydrates is the electrolytes.   If you don’t replace carbohydrates you’ll run out of energy.   If you don’t replace electrolytes, you can die.   Everyone knows that you lose sodium ( salt) when you sweat.   The problem is that if you replace the lost water, without replacing the sodium, you dilute your blood.    When this happens, you get  hyponatremia , which can be deadly.    Dietary sodium sometimes gets a bad reputation, but the fact is that sodium is essential to life.  All of your nerves and muscle use it to send signals.   When the sodium  level in your body get too low, your body can’t properly send these signals.  The result is confusion, muscle weakness,  even brain swelling and death!    Avoiding hyponatremia is easy, just make sure you have that carbohydrate/ electrolyte drink  in your bottle.    My favorite is the Powerbar Ironman Perform*,  but   there are  many on the market.  The most important   factor when choosing a carbohydrate/electrolyte  beverage is that it tastes good ,  and you’ll drink it!   If for some reason you can’t get your hands on any electrolyte drinks, just look for a  salty snack.   Most energy bars have some sodium, you can also look for pretzels, salted nuts, or even a coca –cola to help make sure you get enough sodium.  If you’ve been thinking about a low sodium diet, today isn’t the day.


A tasty   beverage at the finish line will get started on your  post ride rehydration, and the sauce in the pasta feast will replenish even more of the sodium you’ve lost.   Make sure  you  have some more water to go with tasty beverage, as  you will inevitably have lost more water  than you can replace during the ride.   By the time you get home, it will have been a long day, both on the bike and

How often are supplements tainted or contaminated?

So in the last post we discussed the fact that an athlete is responsible for whatever goes into his  or her body, and that it doesn't matter if a banned substance was ingested unintentionally.  If they find it in your system, you are going to  get banned.   Even if it was an accident, and even if it was in non-therapeutic dosage.   So how often  are supplements contaminated?   In 2002 the IOC issued a  report that found that 14.8% of the supplements they tested  were contaminated with testosterone or related compounds, 18.8 % of the supplements  that originated in the US were contaminated.  That is 1 out of 5!  But wait,, it gets worse.... A 2004 study published in the journal Sports Medicine,  found that 40% of the supplements they tested were contaminated with either prohormones or  or stimulants that could cause an athlete to test positive for a banned substance!  Not good.   That is almost half.     I'm not suggesting that a full 40% of all supplements out there are contaminated.  A full 40% of the supplements in that one study were contaminated, but the researches chose mostly  protein powders/muscle building supplements and weight loss supplements.  It is definitely possible that those classes of supplements are more likely than others to be contaminated, but that isn't really the point either.     The point is that  supplement contamination is real and you can get into real trouble if you accidentally take a contaminated supplement.      What is the best way to ameliorate those risks?  Avoiding  supplements in general is probably the best way to avoid accidental ingestion of a banned substance.   If you really want to take supplements though,  there is an independent testing organization called NSF that tests products  (  This organization runs completely independently of the supplement companies, tests their products for contamination, ensures that the label accurately reflects what is in the product inspects their facilities, and will only give their stamp of approval  once their rigorous standards have been met.    NSF even does random " marketplace testing", meaning they don't just  test the stuff the companies give them.  They go to the store and randomly buy the supplements off the shelves and test those  as well.        I am generally of the opinion that most supplements are not worthwhile, but there are a few that are worth taking for some athletes ( that belongs is another post).  If you absolutely must take a supplement, my suggestion is that you march on over to now, and search their list of certified products.    You'll get no promises from me, but that is probably  the best way to make sure you stay clean.  




IOC Report on Supplement contamination:


Sports Medicine Journal Article on   Tainted supplements:

Milk does not produce excess mucous.

Milk does not produce excess mucous.  That is a strange title for  an entry in this blog, but  it seems very appropriate  to my personal situation today.     I am suffering from a wicked headcold at the  moment.  A headlcold that may have been exacerbated by a high volume training cycle I completed on Sunday. ( and therefore relevant to cyclists, training and coaching)    I have  a slow nasal drip constantly coming out of my nose,  and down the back of my throat,  yet I  my head and upper respiratory  tract feel like they are holding so much pressure they are about to explode.    Basically, my head is full of mucous.     ( Doesn't that paint a pretty picture?  I know some might say my head is full of something else) .   I've heard from more than one person today, that I should stay away from milk and dairy, as it increases mucous production.   My first instinct was: " I don't buy it"   But that could be because I love cheese; swiss cheese, cheddar cheese, pepper jack cheese, gorgonzola cheese, I love the stuff.    Cheese is one of the primary  reasons I need to drop 10lbs before track season starts.  (You can guess the other. It start with a B and end with an eer)  The other reason for my skepticism  is that I am not aware of any physiological  mechanism wherein dairy products produce mucous, but I have been wrong before, so I decided to do a little research. The first article I found that came from a reliable source ( ie: journal article or similar)  was this:   Relationship between milk intake and mucus production in adult volunteers challenged with rhinovirus-2.

In this article, they gave people sinus infections, and then essentially  measured their snot by weight, and measured their other symptoms ( such as cough).  What the researchers  found was  "Milk and dairy product intake was not associated with an increase in upper or lower respiratory tract symptoms of congestion or nasal secretion weight."   Basically:  Milk does not make mucous.   They also found what they called  "A trend ... for cough, when present, to be loose with increasing milk and dairy product intake; however, this effect was not statistically significant"  What this means is that basically they think there  may have been a difference there, that milk may have made  the cough  more loose, but that  the researchers did not have enough data or statistical power to prove it.    To me, this seems like like a great reason TO  enjoy dairy while you have a sinus infection.  I would rather couch up some loose phlegm that comes up easily, rather than that thick stuff!

Then I found this:  The Milk-Mucus Belief: Sensory Analysis Comparing Cow's Milk and a Soy Placebo.

In this study the researchers  performed a double blind study, and gave  subject either a milk , or  soy milk beverage that was indistinguishable from the milk .   Subjects reported increases in 3 of the mucous related variables when they drank the test beverage, but the effect was the same for  both the milk, and the placebo soy beverage.   The researchers "concluded that the effect measured is not specific to cow's milk, but can be duplicated by a non-cow's milk drink with similar sensory characteristics."    Bascially, milk does not make mucous, but if you think it does, and if you think you are drinking milk, you may report more symptoms.   I am going off of the abstract on this one, and I would like to read the whole article so I can see a bit more of their statistics and physiology, but I'm not willing to pay $41.95 for the privilege.

Those first two are from the 90s, and I found more from that  time period, but this is the one that really sealed the deal:   Milk Consumption Does Not Lead to Mucus Production or Occurrence of Asthm is a well written review article from 2005 with 49 references.    These  Swiss researchers carefully reviewed the literature and determined that recommendations to abstain from milk and dairy  in order to  avoid  to increased mucous or asthma symptoms  is not supported by research.  They also report that people  who believe  "milk makes mucous"  tend to report increased symptoms with milk consumption, while people that do not believe " milk makes mucous" do not report increased symptoms.   This in itself means nothing, until they point out once again, that people who believe "milk makes mucous"  are easily fooled by a placebo.    The reviewers  go on to say that avoidance of dairy products may lead to limited intake of certain nutrients, specifically calcium.   This might not be a an issue for a cyclist suffering from a short term a headcold, but  fact that I can still enjoy my cheese ravioli for dinner with no fear of extra snot buildup in my head gives me some comfort as I  stay at home recovering ans itching to get back on my bike.


In 2003, I wrote about how milk  is an excellent recovery drink: ( this is a very old version of my old coaching site)

Several studies have confirmed that milk is an excellent recovery drink, and  , and works as well as commercially available recovery beverages for both cyclists, and runners.

Heidi Klum Likes Milk


Coconut Water for Rehydration

Coconut  Water  for Rehydration When I was in Costa Rica this last April, one of the locals I was riding with suggested we stop and have a drink of fresh coconut water.    Coconut water is basically the juice from the inside of a young coconut, before that juice becomes coconut milk.    To have a taste of the stuff, we simply stopped by a roadside fruit stand, and the owner knocked a whole in the coconut and gave us a straw.   The coconut water had an interesting taste, very mildly sweet, and refreshing.   As we sat next to our bicycles,  the local rider started telling me how coconut water was a perfect rehydration drink.   He went on about how coconut water was isotonic, meaning it has the same electrolyte concentration as the blood, and that it was actually used   as IV fluid in place of saline during WWII.    Those that know me, know that I consider myself and “open minded skeptic” when it comes to this sort of thing.  Honestly I thought the local guys was probably full of it, but I was still intrigued and I decided I would investigate further when I returned home.

What I found out actually surprised me.  Not only was coconut water isotonic to blood, but it was really used in WWII and there were several journal articles reporting the emergency use of coconut water being successfully used for IV hydration in place of saline.  Another study suggested that coconut water was just as effective as a commercially available carbohydrate/electrolyte beverage in rehydrating subjects, and the subjects actually had an easier time drinking the coconut water.     Now I had to go find myself some coconut water. ( There are no roadside fruit stands with young coconut near my house).

They don’t have the stuff at the Vons supermarket around the corner,  but I found some at the Pancho Villa Market  just a few minutes away.

The coconut water I found was 70% percent coconut water ( juice)  by volume, with 30% added water and a little sugar.    12 oz of plain coconut water would have about  70 calories, but the added sugar brings the calorie count of  the stuff I bought to about  110 calories per can.  This is still a little bit more than calories than Gatorade, and  about  1/3 less than a can of soda   The extra sweetness is not unpleasant after a long hard ride in the heat,  but I wouldn’t be opposed to have the unsweetened stuff either.  It is actually quite easy to buy canned,  unsweetened coconut water  online, so I'll probably order some soon.

Physiologically I wouldn’t say its “perfect” as an electrolyte replacement drink,  as the sodium is a bit low (it has about half as much sodium as  the same volume of Gatorade).   But then again it is packed with potassium and  you are most likely going to get plenty of sodium  from your post exercise meal.    it is  really a little low on sodium for use during exercise, but is pretty good as a post exercise drink.  Some studies have even shown that  potassium  is  highly important for maintaining proper blood pressure and heart health, so the extra potassium  could be a bonus.

My personal verdict?   My fridge is almost always  stocked with a few cans of coconut water these days.  It has become my go to beverage when I get home from a long ride.  It tastes good , gives me a few carbohydrates, and  replaces some of those lost electrolytes.

So  now is the time where I give you my shameless plug for your chance to try FRESH coconut water.   We are going to have a Crank Cycling training camp in Costa Rica this February.  It will be a weeklong camp where you can ride every day, relax by the hot springs each night, and sip  fresh coconut water    straight from the coconut.  Stay tuned for details.