Episode 149

Kava comes from the roots of Piper methysticum, a plant that is a member of the pepper family.  It’s a traditional drink in many Polynesian cultures.  It’s a social drink that could be seen as a South Pacific version of alcohol.

Unlike alcohol, however, there’s no negative cognitive impact.  In fact, many people report their mind feels more alert after taking kava.

Dr. Jerome Sarris, Senior Research Fellow at the University of Melbourne, talks to us about why you should take kava, what’s going on in your brain, and a surprising benefit.

The Benefits of Kava

One of the major therapeutic uses of kava is as a treatment for generalized anxiety disorder.  A large percentage of people with anxiety will experience reduced anxiety after taking kava.

If you’re not struggling with anxiety, kava boosts your mood above baseline.  You’ll feel more relaxed, content, and loquacious.  Dr. Sarris says it’s generally a very pleasant experience.

These effects sound a lot like those of alcohol, but there’s an important difference:  kava doesn’t negatively affect cognitive ability, unlike alcohol.

Kava also has an analgesic effect, relieving pain and relaxing muscles.

And there’s a final, slightly salacious benefit — studies indicate that kava seems to increase women’s sex drive.  Of course, as Dr. Sarris points out, this is a common sense finding.  If you’re feeling anxious and stress, no matter your gender, your sex drive is going to plummet.  If you can reduce anxiety, you’re more likely to feel “in the mood.”

How Kava Works

Coming from a plant, kava contains a huge number of substances.  The major active compounds you should know about are the kavalactonesKavain seems to particularly responsible for the analgesic properties of kava.

What’s happening in your brain?  Kava is a reuptake inhibit of noradrenaline (also known as norepinephrine) in the prefrontal cortex.  That’s why it doesn’t impede cognition, and you actually feel more alert and “buzzy” mentally.

It also has a strong gabaergic effect, which is responsible for making users feel more relaxed and decreasing anxiety.

How to Take Kava

There are two ways to take kava:  in a pill or in a drink.  Most people taking kava for therapeutic purposes take it as a pill, since the drink tends to be very bitter.

Dr. Sarris recommend taking 60-120mg of kavalactones twice a day.  You can take a higher one-off dose as a pain killer, but you should not take more than 250mg kavalactones per day.

Want to try kava?  Dr. Sarris recommends looking for capsules standardized to 50-60% of kavalactones.  Bonus points if it’s Fijian kava, since they are considered to be of high quality.

Who Should Not Take Kava?

Kava is generally very safe.  Unlike substances like alcohol, kava has no physical addiction potential, since it has no dopaminergic effects.  That’s not to say that psychological addiction isn’t possible, however.

Most people should be able to try kava and see if they like the effects.  However, some people should avoid kava.  Don’t take kava if:

  • You have severe depression
  • You’re taking alcohol or benzodiazepine at the same time
  • You have pre-existing liver issues

You may have heard about potential liver damage caused by kava.  We still don’t know why kava may cause liver damage.  The good news is that only a handful of people who take kava will develop liver damage.  It could be due to poor quality kava or some genetic predisposition.

Whatever the reason, to be on the safe side, avoid kava if you have any problems with your liver.

Episode Highlights

0:23Plant-based ceremonial drink kava
1:16This Week in Neuroscience: Study identifies brain areas altered during hypnotic trances
4:00The audience interaction section
5:49What is kava?
7:11Intro to Dr. Jerome Sarris
7:39How kava is used
8:56Kava versus and antidepressants and psychological techniques
9:36Is liver damage a worry?
11:06Kava’s mechanism of action
12:09Why would someone want to take kava in pill form rather than in drink form?
12:40Dose-dependant inebriation
13:24Acute effects
15:46How well-known is kava?
16:27Who should and shouldn’t use kava?
17:27Kava versus alcohol
20:18Anxiety levels and kava use
21:44Increase in female sex drive
22:31Dr Sarris’ current research
25:13Ruthless Listener-Retention Gimmick: Walking with coffee: Why does it spill?

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Episode Transcript hideshow

— This Week in Neuroscience —

Jesse: So, back not terribly long ago in episode #141, we talked with Dr. David Spiegel about hypnosis.  Dr. Spiegel is at the Stanford University School of Medicine and is one of the world’s leading authorities on hypnosis, and was also the head author of a recent study looking at what distinguishes a hypnotic trance as far as what’s going on within the brain versus other brain states—sleeping, waking, etc.  To perform this study, Spiegel and his colleagues screened 545 and 45 healthy participants to try to find people at the high and the low ends of the hypnotizability spectrum.  Some people are much more hypnotizable than others.  About 10% of the population is found to actually be highly hypnotizable; some people, not really at all, and most people falling somewhere between those two extremes.  From this group of 545, they wound up pulling 36 highly hypnotizable subjects and 21 control subjects who are among the least hypnotizable they were able to find, and then studied the whole group of them under fMRI, looking at the changes in blood flow in the brain as they’re performing various hypnotic behaviors, to see just where the differences lie. 

Says Spiegel, "It was important to have people who aren’t able to be hypnotized as control subjects, otherwise you might see things happening in the brains of those being hypnotized but you wouldn’t be sure whether it was associated with hypnosis or not. 

The study came away with three main findings.  First, they saw a decrease in brain activity in an area called the dorsal anterior cingulate, which is a part of the brain’s salience network, basically meaning that you’re dimming down attention to the outside world.  Secondly, they saw an increase in connection between two areas of the brain called the dorsolateral prefrontal cortex and the insula.  This is an increase in the connection between the brain and the body, helping the brain process and control what’s going on in the body.  Which may be why hypnotic states have been so effective in pain control, with the subject being able to say, "You know what?  This surgery doesn’t hurt so bad.  I stubbed my toe earlier, I can’t even feel it." 

And finally, the researchers observed reduced connections between the dorsolateral prefrontal cortex and the default mode network.  The default mode network is also the network within the brain that quiets down for meditators during states of meditation.  Spiegel describes this reduction in activity as being responsible for the hypnotic state’s famous disconnect between somebody’s actions and their awareness of their actions.  Not that a hypnotized subject doesn’t know what’s going on necessarily, but that they’re not self-conscious about it.  "When you’re really engaged in something," Spiegel says, "you don’t really think about doing it.  You just do it."  This freeing up of mental resources might account for some of the cognitive processes that could actually be done better under hypnosis than they can in a normal waking state.  So further evidence, as if we needed more, that hypnosis is a distinct mental state characterized by unique patterns of brain activity, but still present so many interesting mysteries.  Why do the brains of some people slip into this state?  Why don’t others?  And how did this capacity evolve?  Or did it evolve for something else and hypnosis itself is just sort of a lucky happenstance? 

— Main Interview —

Jesse: So we’re going to be talking about kava, and kava is actually not just one plant but a plant family found throughout the South Pacific.  Lots of different strains, which, as you might imagine, have slightly different psychoactive components within them, so not all kava is going to be the same, but there are a lot of commonalities.  Kava can be used to produce a drink, which has sedative, anesthetic, euphoriant, and entheogenic properties.  Euphoriant, you can probably determine, comes from the word euphoric, and entheogenic means "god-generating," which doesn’t necessarily mean that a god or a genie is going to appear in a puff of smoke in the air before you, but that’s a term that’s often used in psychedelic compounds.  Kava is not considered a psychedelic, but it definitely does have recreational drug qualities.  However, where those qualities come on vs.  things like anxiety reduction, pain reduction, that’s very dose-dependent. 

Now on the image for this episode, we actually have a pretty kava flower, but the extract made from kava comes from the root.  I couldn’t find an attractive picture of the root, so we didn’t go with that.  And apparently there’s also a small tree in New Zealand called the kawakawa which is often confused with kava but is not the same thing.  It’s also sometimes called Maori kava, but psychopharmacological two different things, so do not be fooled.  Finally, you may be wondering is kava legal.  The answer in the US is yes, it is a totally unscheduled non-regulated compound sold in health food stores, you can get it in liquid extract or capsule form.  There are other countries that are less kava-friendly in their laws, so if you’re outside the US, check your local regulations. 

So in this interview, we’re going to be talking with Dr. Jerome Sarris, he’s from the University of Melbourne, where he is a senior research fellow in the Department of Psychology.  He began his career with a clinical practice as a naturopath, nutritionist, and acupuncturist before completing a doctorate and moving on to more academic work.  And he has a particular interest in anxiety and mood disorder research, which will relate directly to kava, because as you will hear, one of the standout properties is anxiety reduction. 

So let’s jump in now with Dr. Jerome Sarris. 

Dr. Sarris: It’s got a very rich use in Polynesian cultures for both recreational use as well as medicinal and therapeutic use.  It also has a bit of a psychospiritual and religious element in some cultures.  But they’ve used it for centuries for a range of ailments.  It could be for improving mood-decreasing stress, relaxing the muscles, as an analgesic or anesthetic; but also for lesser known applications, such as for urinary infections and other gastrointestinal infections as well.  We’ve conducted several clinical trials.  We’ve looked at kava’s effects acutely, so just taking a few tablets of kava and seeing if there’s an instantaneous effect; we’ve looked at kava in respect to the effects on driving, on cognition.  But our major work is looking at kava in respect to its effects on people with chronic anxiety.  So we have, to that end, conducted two randomized placebo-controlled double-blind studies with people with both a chronic clinical anxiety disorder known as generalized anxiety disorder, but also just in people with general raised levels of both stress and anxiety.  In both cases, we found a significant effect with the kava reducing anxiety beyond placebo.  We’re currently conducting a much larger double-blind RCT looking at kava vs.  placebo to really get a very, very clear conclusion regarding its anxiolytic effects. 

Jesse: What is the current medical standard of care for general anxiety disorder that kava would sort of be held up against to see if it outperforms? 

Dr. Sarris: Generally, antidepressants, so that would be mainly the SSRIs.  But also psychological treatments, such as cognitive behavioral therapy.  Or the combination of both.  In the old days, they used to prescribe benzodiazepines, such as valium, but as we know, there can be issues with dependence, with tolerance, and withdrawal effects, as well as a range of negative side effects, so they tend not to be prescribed long term.  So kava, really in terms of its efficacy, it will be compared to primarily antidepressants and psychological techniques. 

Jesse: I’ve read that there are concerns about potential liver damage.  How real a threat is that with kava? 

Dr. Sarris: It’s something we certainly have to be cautious of.  We have to understand that, in respect to other medications—for example, over the counter paracetamol—it is far, far safer.  But there has been documented negative effects on the liver, and while these are incredibly rare, it is something we still have to be mindful of, because the reality is we do not know, categorically, why these events have occurred.  We’re talking in terms of what we can say is highly probable kava-related liver injury, and we’re talking a handful of cases. 

Jesse: Interesting.  So it’s not like a small amount of wear and tear that people are going to get regardless, it’s that some people have a very strong adverse reaction? 

Dr. Sarris: That’s what we’re thinking, and I wish I could give you a very clear answer, but the fact is that it’s still something which we’re trying to elucidate.  My personal academic perspective based on the literature is that it could be due to poor quality kava; maybe the incorrect cultivar had been used, because there’s different types of kava.  That, in combination, perhaps with somebody with a genetic predisposition, somebody who has, I guess, a predisposition towards maybe not being able to detoxify the constituents in kava.  It could be potentially some constituents which are innately hepatotoxic within some forms of kava, which for most people maybe they don’t get much effect from, or maybe a little bit of minor liver inflammation, but for very rare cases some people may have the predisposition genetically, that inflammatory effect actually does have a very negative effect on their liver.  That could be the case, but even that is just speculation, and we certainly need to do more work to determine what’s going on. 

Jesse: What do we know about mechanism of action, how many bioactive compounds might be within the kava extract? 

Dr. Sarris: We do know that the major therapeutic constituents are known as kavalactones, and there’s six major ones of those.  And it’s the kavain and the dihydrokavain, which are the primary anxiolytic constituents.  However, there are other kavalactones, and one of them, for example, dihydromethysticin, is involved more with the hangover effects, more of the nauseating feelings some people can get from kava.  So quality types of kava, which are known as noble cultivars, contain higher of the anxiolytic kavalactones and lower of the dihydromethysticin, which gives some of the negative effects.  But in terms of hepatotoxic constituents, the actual kavalactones are regarded as not being hepatotoxic.  So it could be other constituents, such as the flavokavains, and perhaps even unknown constituents.  There are some which are found in the aerial parts, such as the alkaloids in the piper methysticum, which is also hepatotoxic, but these are found very, very rarely in any type of therapeutic formulation. 

Jesse: When you were designing your studies, how come you chose to go with a pill form vs.  the traditional form which you would drink? 

Dr. Sarris: I guess the short answer is if anybody has tried drinking kava, that’s probably your answer right there, that it can be a little bitter and unappealing to the Western palette.  It’s an acquired taste.  So I guess in terms of drinkability, there’s issues.  But mainly from a drug study point of view, you really want to make sure you’re standardizing the intervention which you’re giving, and via a tablet or a capsule is the easiest way to do that, meant to obviously further assisting compliance. 

Jesse: In some ways, this sounds like it’s used ceremonially and culturally in ways similar to alcohol.  It’s obviously not quite the same thing.  But are there any risks of abuse or dependency or any of these things that we associate with some of the downsides of alcohol? 

Dr. Sarris: That’s absolutely right.  I guess the first thing is to say, for some of these cultures, they do use kava, as we would in the West alcohol, in terms of it being a dose-dependant inebriant.  So the more you have, the greater a sense of inebriation you get.  So, look, it certainly can be used as one would with alcohol.  However, used at the therapeutic dose, or a milder or more moderate dose, you can get the anxiolytic effects without the issues in terms of being inebriated. 

Jesse: What is the timeframe of the effects?  You said it’s an acute effect.  How long does it last; what’s the half life? 

Dr. Sarris: Well, the half life depends really on the kavalactone, they all have different half lives, and it does give a dose-dependent effect.  But usually we prescribe kava clinically twice a day in order to sort of get a steady state.  Usually between about 16mg and 120mg of total kavalactones twice a day.  That being said, it can be used at a higher dose more intermittently, let’s just say an hour/hour and a half before an anxiogenic event in order to reduce anxiety.  But of course, we have to look at individual jurisdictions in terms of giving prescriptive advice in terms of what the recommended dose is.  And certainly what we don’t want to do, with some liver concerns, is to advise people to be having lavish amounts of kava.  The work I do is more couched around a therapeutic medicinal approach, which is using lower amounts. 

Jesse: Other than the anti-anxiety effects, which sounds kind of like the primary cognitive effect, can you talk about other perceptual, experiential, or cognitive processing effects? 

Dr. Sarris: I can certainly say from my own experience, occasionally I’ll have more of a traditional kava session, in which case you consume a few bowls of kava.  Depending on how much you have, it’s still in the system the next day and you may feel a bit tired, a bit sluggish.  But it’s actually not a bad feeling, sometimes it’s good to sort of wind down and to have it.  But what I would say is what separates it from, say, alcohol or a benzodiazepine is that it doesn’t have any negative effects on cognitive ability.  We’ve done some research; we did an acute RCT comparing kava to the benzodiazepine oxazepam, and placebo.  So I guess an average therapeutic dose acutely, there was no difference in respect to cognitive function.  There was some reduced cognitive function with the benzodiazepine, but not with kava.  Now at higher levels, that’s not to say if a person didn’t consume a fair bit recreationally that something wouldn’t be happening cognitively.  What’s interesting about kava which delineates it from, say, alcohol or benzodiazepines is that it a reuptake inhibitor of noradrenaline in the prefrontal cortex, as well as having fairly strong GABAergic effects.  So with the effects on the GABA pathways, a person can feel very physically relaxed, it’s a strong muscle relaxant; they can feel, I guess, a reduction of anxiety.  But with this noradrenergic effect, it doesn’t impede cognition, and in some cases people will have the experience of sort of feeling a bit buzzy and a bit more alert mentally, which is certainly in contrast to our sedatives. 

Jesse: Outside of the traditional regions where the kava plant grows, what do you feel like the level of awareness is?  How many people know this plant exists vs. might now in five years? 

Dr. Sarris: I think in respect to the American market, there is I think some awareness, some knowledge of it, certainly in respect to people who use plant medicines for medicinal purposes.  I mean, there are kava bars popping up all over the place from what I can understand.  There’s a reasonably buoyant market, people buying kava tablets and powders and teas and so forth.  I think what the issue was is that because there was a little concern about the quality of kava and liver issues in the early 2000s, it affected a bit of the supply and use of kava.  But I think that’s steadily rebounding. 

Jesse: Other than people who might have concerns about their liver health, are there other caveats or red flags, people that might not be good candidates for trying kava? 

Dr. Sarris: In my personal experience and clinical experience, a medicine for one person is potentially a poison to another.  I think there are a range of individual differences, primarily mediated potentially by individual genetic differences between people.  But for some people who try it and see whether it works for you, I guess just the overall caveat is that in people who have higher levels of depression, especially if they have unipolar depression with low levels of anxiety, I would not prescribe kava.  In cases of people combining with alcohol, combining with benzodiazepines, I would certainly be wary of that and co-medicate.  People with preexisting liver issues should be probably warned away from kava.  Aside from that and aside from some of the potential liver concerns, which, as I said, are very, very rare if used in responsible amounts, it’s a very safe plant medicine. 

Jesse: In cultures that do make use of kava, I wonder if we see less use of alcohol.  Does it really step in for some of the cultural use of alcohol that we would see in other parts of the world? 

Dr. Sarris: It depends on the culture.  For some cultures, I think where kava is part of their cultural fabric and their religious fabric and it’s used in more of a ceremonial, familial context, then I think, yes, it can have a role in respect to keeping people consuming kava and not alcohol within that particular cultural framework.  However, in other cultures, such as if we look at the native Australians, the indigenous Australians, they tried that experiment up in the northern territory with very good intentions, thinking that it could reduce alcohol consumption by some communities by swapping with kava.  Now unfortunately what happened is that the community said, "Yeah, that’s great.  We’ll use both."  Look, combining both certainly does have a very intoxicating effect, but then you double down on the potential for very negative health effects. 

Jesse: Does kava have an addictive potential the way that alcohol does? 

Dr. Sarris: No.  My understanding in respect to the epidemiological evidence and also a small study we did looking at the effects of people taking medicinal levels of kava and seeing when they went on to, unbeknownst to them, a placebo, whether, in a runout phase, when they transferred from kava to placebo, whether they had any withdrawal effects or any desire to take kava again.  And also to increase their dosage throughout the study, there was no difference over placebo.  Now, that should be taken into context with the effects of medicinal use, that should be taken in the context of recreational use.  In some cases recreational abuse, where, from what I can understand pharmacologically as well as epidemiologically, there is not necessarily physical addiction, so it’s not as if people are necessarily hanging for another hit of kava.  However, there can be psychological addiction in respect to people’s usage—which is, you know, obviously a fairly complex thing to analyze because you have a lot of psychosocial factors impacting that as well. 

I can only say, just from a personal perspective also, I possibly do have a mildly addictive personality, nothing major or anything, but I know if I like something, I want to try it again.  With kava, yeah, I enjoy it, have a session now and then, but the next day I’m not clamoring back to the kava bowl to get another hit of it.  But then again, that’s just a sample of one.  I think if we want to look at it pharmacologically, there has not been pronounced dopaminergic effects found, which would have that reinforcement.  Potentially you could argue, with using higher levels, it may have effects on tweaking the GABAergic system, and then maybe the person could potentially have a withdrawal effect with respect to wanting to reinforce the GABA effect from kava and thereby wish to have it again.  But that hasn’t been necessarily well-documented, and certainly there’s nothing to suggest that would be a similar effect that you would get with another GABA agonist, such as a benzo. 

Jesse: In cultures where kava is widely known and used, I’m wondering if it’s seen to be used more by people who tend to be higher on the anxiety spectrum. 

Dr. Sarris: That’s an interesting question: do you have to be anxious to get effects, or greater effects, from kava?  I guess we can look at it culturally.  If you look at the South Pacific people, I think it would be fair common sense to say they’re very relaxed, and they’re drinking kava and they’re enjoying it and getting the effects from that.  Now, I don’t necessarily think they are relaxed because everybody’s drinking kava; I think obviously it’s culturally mediated.  And different Pacific communities have differing rates of kava use.  And also different contexts—some islands, it’s applied more religiously, it’s more recreational use.  So, what I’d say is they’re definitely obviously getting an effect, otherwise why on Earth would they drink it.  So for them, they would be getting a pleasurable effect.  I think some people would be using it obviously medicinally to treat their anxiety.  And I guess the question is, if you’re a healthy person, you don’t have anxiety, why effect are you getting?  Because we do know that people who drink kava who’ve got anxiety, at least a good percentage of them, will have their anxiety reduced.  But if you don’t have anxiety, from what I can perceive, I guess ecologically, in attending a lot of these kava sessions with Pacific people, is that it lifts their mood, so they feel very relaxed physically and a bit buzzy.  And yeah, they tend to be more loquacious, so they sit around the kava bowl, they tell stories, they connect, and yeah, generally it’s a very pleasant experience for them, which I guess is a different use or application compared to somebody taking a few tablets a day to reduce their anxiety. 

Jesse: One of the things I also read in your studies was a potential increase in women’s sex drive.  Can you talk a little about that? 

Dr. Sarris: Well, I don’t know if I can personally talk about it… 

Jesse: Well, you know, what’s the data say? 

Dr. Sarris: Yeah, yeah, sure, sure.  Looking at the data itself, we found a very curious finding, and that is, looking at the Arizona Sexual Experiences Scale, the ASEX, that on the subscale of sex drive, that women had an increase in the kava group of their related sex drive compared to placebo, and that this was correlated with the level of their anxiety reduction.  I mean, that makes perfect sense; this wasn’t found in men.  I mean, this is just me theorizing, but it could be just a very common sense finding that if a female has anxiety and stress reduced, then their sex drive can return and sort of has a beneficial effect in regards to that. 

Jesse: And you’ve got ongoing research.  Can you tell us a little bit about that? 

Dr. Sarris: The current clinical trial we’ve got going, which is quite exciting, quite novel…  The kava we’re using is a water soluble form of kava, which is from the noble form of kava, so very good quality kava, using pure rootstock.  There were some issues in Europe back in the early 2000s, and in various parts of the world, in terms of, as we know, liver issues.  Part of the concern was that the wrong types of kava, the incorrect plant parts as well as using chemical extractions of the constituents, could potentially be implicated with the toxicity.  So, the WHO advised that future research looked at noble cultivars in which just using the pure rootstock and a water soluble extraction method, which is how it’s used traditionally.  So, we’ve been doing our research for the last several years and it’s led us to this point.  We’ve got NHMRC, which is the equivalent of the NIH, funding our research and we’re doing a 16-week RTC looking at kava vs. placebo in a sample of a couple hundred people.  So, it really should give us a definitive answer in respect to kava for GAD, or Generalized Anxiety Disorder. 

But what is very interesting about this research is that we’re also looking at, say, analyzing genetic differences between people in respect to some of the genes which we believe are implicated in determining whether people have effects from kava; as well as doing some brain imaging, so some fMRI, to see if there are any brain differences in people who respond; as well as seeing whether there are differences in GABA levels in people’s brains, which is the main inhibitory, relaxing neurochemical.  So seeing whether there are differences in people’s brains in the kava group and the placebo group and whether this is linked to people’s response to kava, as well as looking at the gene expression of GABA between the groups.  So, we’re combining some pretty novel science as well as a really high-powered RCT to really tease apart how kava is working, in which people kava is working, and then overall if it’s effective and safe. 

Jesse: So, thank you so very much to Dr. Jerome Sarris for taking the time for that conversation.  It was funny what he said in there: you hate to make broad sweeping generalizations, and obviously I’m sure that there’s more to it than just kava, but our mental image of South Pacific islanders is a pretty laid-back, relaxed sort of place, culturally speaking, and it makes you wonder to what extent kava usage might be a part of that.  It sounds like the drink itself is probably an acquired taste, not something you might like at first blush, but of course it’s available in pill and capsule format.  There were a couple of contraindications there, and the question on the strong adverse effects on some people’s livers.  It sounds like there’s still some unanswered questions, but interesting plant compound, sounds well worth knowing about, and unlike a lot of things, probably not terribly difficult to get one’s hands on and give a try, should you be so inclined.  But now going from kava to coffee, let’s jump ahead to the Ruthless Listener-Retention Gimmick. 

— Ruthless Listener-Retention Gimmick —

Jesse: And in further evidence that some scientists seem to have too much time on their hands, researchers at the University of California at Santa Barbara have been looking into this sloshing of coffee inside coffee cups, and how both the person’s gait, the way that they walk, and the design of the coffee cup itself can make dangerous sloshes more or less likely.  While attending a fluid dynamics conference, the study’s author, Rouslan Krechetnikov, realized that scientists, who should know a thing or two about fluid dynamics, were still sloshing coffee on themselves when they were trying to walk back and forth between conferences and the little coffee dispensary, and this got him thinking that a study was merited.  The physical mechanics of sloshing coffee in a cylindrical container are actually pretty complex.  The radius of the container, the length and speed of the person’s stride, whether somebody has a limp or a little sort of side-to-side sashay when they walk—all these things factor in.  But rather than get a lid, these researchers wanted to get to the bottom of how both coffee cups and walking could be maximized to limit spills.  The big surprising takeaway findings are that the easy wins are starting your walk slower—that is, accelerating less; leaving a decent-sized gap between the top of the coffee and the mug’s rim—duh—which, Krechetnikov says, should be at least 1/8th of the mug’s diameter (for a normal mug that would be about 1 centimeter).  And don’t be embarrassed to watch your coffee while you walk.  They tested two kinds of coffee carrying, one where the person’s watching carefully where they’re walking towards and ignoring the coffee, one where the person is ignoring where they’re walking but watching the coffee carefully, and the coffee watchers did better on this test. 

Liquid sloshing, as innocuous as it sounds, is actually a pretty big deal, and things like tanker trucks that carry large quantities of liquid actually have internal baffles, as they’re called, to add some friction and prevent sloshing, because otherwise sloshing liquid could actually overturn a big truck.  But it’s probably unlikely to expect internal baffles in a coffee mug anytime soon, although it would be possible.  It’s a whole lot more cost-effective to simply add a lid.  The researchers have not stated whether they’ll continue their work beyond merely cylindrical mugs, nor has anyone answered sufficiently the question of why martini glasses are designed the way they are so that they are almost impossible not to spill.  At Smart Drug Smarts of course, we recommend drinking from a fluted beaker.  If you think of one of those wide-bottomed beakers from chemistry class with a little narrow top, those things are hell to clean, you don’t want to put anything sticky inside of them; but boy, they’re impossible to spill.  Plus, if you’re drinking out of them, you look like a mad scientist and that’s gotta be worth something. 


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Written by Hannah Sabih
Hannah believes there's nothing 8 hours of sleep and some kale can't cure (yes, she's from California). She's an avid runner, reader, and traveler, who brings you the latest and greatest in neuroscience via our social media channels.