What's That Rash? - What has your nose got to do with sleep_

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0:19Speaker 1This Science Week, we're celebrating Australia's wildflowers. Vote now for Australia's favourite at abc.net.au slash science. Celebrate Science Week with us in August on ABC Radio National and at abc.net.au slash science. Do you have any hacks for getting yourself to go back to sleep when you wake up in the middle of the night? Look up.

0:43Tegan TaylorI don't. Apart from scrolling the NEJM. Or sending you an email at two in the morning. Sending you emails from the Lancet. I do find that if I just don't lift the phone, I do go back to sleep. So that's my hack. Just don't lift the phone. Okay, so the screen doesn't work, so then genuinely next time you send me a text or an email at three o'clock in the morning, I'll say you're breaking your own rule. You will indeed. It's a while since you've had one. You might notice. I just thought you didn't love me anymore. I thought you were sending them to Shelby instead. No. I don't want to wake up Shelby.

1:12Norman SwanI know she's sound asleep. My notifications are off. Well, sneaky, sniffy sleep hacks is actually what we're talking about today on What's That Rash? The show where we answer the health questions which simply everyone's asking. So, Dar emailed in about a sleep event they went to where one of the experts made a throwaway comment that if one is having difficulty getting back to sleep, try smelling a...

1:41Norman Swanpungent order as it breaks some receptors in the brain or something like that. I was taken by the comment and I wonder if it would be possible for you to explore this topic further. Well, you're partly to blame for this event, aren't you, Tegan? This is an event that I was part of, a non-ABC event. This throwaway comment intrigued everyone. So I'm actually glad that we have an excuse to talk about it.

2:02Tegan TaylorAnd it really, Norman, has opened a... I don't want to say Pandora's Box because that was bad. It has opened a treasure trove of nose and sleep-related research. So much more nose and sleep-related research that I thought was possible. So let's just get the obvious out of the way so we can just talk about it normally. We are not talking about farting under the covers. Of course. That's where your mind went. Right? So we're not... And sadly, sadly, we're not talking about that.

2:33Tegan TaylorI mean, we can talk about whatever we want. It's our podcast. If you want to talk about farting under the covers, maybe that's the perfect sense for the law to smell. No, that's the subject of another podcast all together and we're not going to talk about it. Okay. We actually have done an episode of What's That Rash on farting. I do recommend going back and listening to it. I got to use a whoopee cushion more than once as a sound effect. No, but we are talking about scents, C-E-N-T-S and sleep. And when I think of...

3:01Tegan Taylorsense and sleep Norman. I don't think about farting. I actually think about lavender. That to me is the thing that's sort of culturally most attached to sleepiness. So maybe that's where we start because it actually has quite a long history as sort of a sleep adjacent herb. Yeah, sleep adjacent. I mean, originally there were therapeutic properties attached to lavender. The English botanist John Gerard in the 17th century described various ways that lavender could be used.

3:27Norman SwanAbbas Hildegard in the 12th century mentions that lavender shouldn't be used as a food, but as a strong scent that might help with lice and evil spirits. So lavender has been around a while, in a sense, as aroma therapy. But even 100 years ago in the 20th century, it was still not about sleep, the use of lavender, but it's become synonymous with sleep in the recent years. Yeah. I mean, in the early 20th century, it was used as effectively an antiseptic, which is

3:56Tegan Taylorinteresting but probably not that relevant sidebar. It really wasn't until aromatherapy took off in the 1930s onwards and then aromatherapy really kind of had a big moment from about the 70s onwards and lavender has sort of taken to the fore in terms of the herb that people associate with sleep. I don't know if it's just because it's like relatively easy to farm. It smells kind of nice. What sort of evidence do we have that it actually helps with sleep though Norman?

4:23Norman SwanSo it's not as if there's no evidence. There has been some evidence that certain aromas such as lavender, chamomile, jasmine have been associated with improved sleep quality reduced anxiety. Why should we be surprised at that? Because when you sniff something in and it interacts with the olfactory epithelium, the olfactory lining at the top of your nose, that's brain adjacent.

4:48Norman SwanAnd the connections to understand why aromatherapy is not necessarily nutty is that this part of your brain seems to have a direct line to your amygdala. And your amygdala is that part of your brain which processes the emotion associated with memories. And so it is conceivable, preferably conceivable physiologically, that something you sniff has a direct effect on the brain. And certainly you can

5:17Tegan Taylorimagine we've all experienced orders that make us feel unwell or make us feel alert or more stressed. So this is not a nutty idea here at all. I think it's worth pointing out that some of these studies are actually funded by companies that make smelly products like aromatherapy. So there are potentially some conflicts of interest to play here too. There aren't either. The other thing I wondered about as well is whether it becomes a bit Pavlovian, that if you start to spray some lavender essential oil on your pillow before you go to sleep each night then you start to associate that smell with sleepiness and then when you smell it your brain sort of goes to a sleepy place teaching yourself that this is a sleep cue. And it's interesting that you say teaching yourself because there's increasing evidence before we get to this whole idea of getting yourself back to sleep by inducing quite acute smells.

6:10Norman SwanThere's increasing evidence that brain training, cognitive training to try and prevent dementia, maintain your cognitive function, is enhanced with olfactory training, smell training. What? Yeah. Small study, an Australian study, where you would do traditional cognitive therapy, maybe cognitive training, I should say, which involves processing speed, memory training or something like that. Then you, at the same time, do smell training.

6:37Norman Swanwhich is actually smelling. Smell training and merging my nose like lifting weights. Well, it is like lifting weights. So you get specific orders and you sniff them and you sniff them on a repeated basis. You know, there are sticks which do this and you can actually repeatedly train your brain to remember certain orders and be able to pair them. And it seems to enhance general cognitive training. It does your head in, but it's thought to be part of this notion that your sense of smell goes directly into the brain itself without other parts of the brain being involved. So normally when we experience something in our environment it goes through our conscious brain, the cortex then into the thalamus which is deeper into the brain and then into other parts of the brain in terms of the hippocampus and memory, amygdala and emotion whereas odours seem to go straight from your nose up to the amygdala bypassing all that.

7:30Norman Swanand is thought to stimulate the brain and create a situation. This is the theory where it allows cognitive training to occur. So this is just general stuff about how those whole idea of aromatherapy is not job stuff. This is stuff which has a physiological effect. It may not be that specific aromas have specific therapeutic effects, but it could be.

7:54Tegan TaylorMy brain is racing now, Norman. I'm wondering if you're using sense to ward off dementia or as part of that brain training. Are like similiars less likely to get dementia than the average person? That's a very good point. No idea. Further research is required. Okay. So we're talking about smelling and sleep. We're talking about lavender. Maybe it helps you get to sleep. Maybe it doesn't. Maybe you've trained your brain to do that. What about in the other direction? Can you have a smell so strong that it rouses you from sleep?

8:24Norman SwanWell, we're notoriously bad at being roused from sleep by smells. So for example, if there's a fire, smelling smoke doesn't always wake people up. Even though you might be able to measure a response in the brain, which is why you need fire alarms, you need sound as well to do that. People have shown that you can interfere with sleep with, say, peppermint and you get certain cranial nerves, nerves that come directly from the brain stimulated by smells such as peppermint. And so there is a specificity to some odors. What about like smelling salts? Well, that goes to the story that we started this with, the question that we started with, which is the event that you chaired where they talked about really pungent odors having an effect on the brain, which allows you to go back to sleep.

9:13Tegan TaylorRight. Do you want to tell us about that research? Yeah. So basically it's not really, it's not really research, but it's people who are in this space who've kind of figured it out for themselves. So the event that I was part of included Professor Bruno van Swindren from the Queensland Brain Institute at the University of Queensland. And he sort of threw this out as like, oh, if you want to tip to like get back to sleep if you wake up in the night, do what I do and smell strong odor. And I will admit now Norman that we're deep in the episode that I originally thought about farts as well. I was like, what, you just ask your partner to fart and stick your head under the covers. I don't know.

9:42Tegan TaylorIt's more complicated than that. But I basically went back to Bruno and asked him to explain in more detail, which of course he did. And he said he learned the trick from a sleep research colleague. And he says it has a solid basis in neuroscience. And this is coming from someone who is a neuroscientist. So I'm believing him.

10:01Tegan TaylorHe says, insomnia is often caused by anxiety, which involves a part of the brain called the amygdala, which you mentioned before. You often go into sort of anxious loops that are hard to snap out of, hence the insomnia. Smell, as you said before, Norman, is the only sense that bypasses the thalamus filter. It goes straight from the nose to the amygdala for some reason, which is why odors often evoke strong emotional responses, as we said. So if you can smell a strong odor while you're in one of these anxiety loops, that odor can kind of break the cycle momentarily, reset your brain and kind of help you go back to sleep again. But he said, there's a couple of things. It has to be strong odors and you have to not know what it is.

10:43Tegan Taylorbefore you smell it. It's going to be a surprise. So what he's got is a collection of little vials next to his bed. Vile vial vials. Vile vials. So one has nyok mam, like, you know, a fish sauce, lavender is one, aftershave, vinegar, cloves, and then has them randomly next to the bed, waking up in the night, feeling anxious, getting in that loop, can't break out of it. Pick a violet random, copper sniff.

11:10Tegan TaylorPut the lid back on, go back to sleep again. And he said it, he says, I can't guarantee it will work for everybody, but it did work for me. And the neuroscience makes sense. Indeed. It reminds me of our episode on cramps where pickle juice. Yes. Which you mentioned because you had a, Norman, our correspondent, had a cramp and found that pickle juice did in fact work. So you think it's something to do with the shock?

11:38Norman SwanWell, that's the theory behind pickle juice is it hits the back of your throat and does something neurophysiologically to reset your brain. And according to our correspondent Norman, it works like a dream. Works like a dream that turned into a nightmare that turned into a pickle juice cramp. I don't know whether Yannick Sinner, when he can't sleep at night because he's worried about his next event, you know, sniffs pickle juice. Snort the pickle juice, it'll get you out of the anxiety spiral and solve your cramp problems.

12:07Norman SwanAnd this direct line that you've got to the brain makes sense because, for example, with fire, you don't want any delay to your response to an odor that might actually preserve your life, might actually save your life. Hang on. You told us that smoke didn't wake us up. Exactly. But if you're roaming through the savanna grassland with your family group and you sniff in the air and you smell smoke, that presents an alert.

12:34Norman Swanyou might actually have a sense in the olden days, you might have had a heightened sense of smell of animals in the environment and just the way animals can smell danger, we might be able to smell it too. We might have lost the awareness of that. And then there's much more positive things where you

12:51Tegan Taylorsmell just gets into your memory where a certain food smell certain smell of cooking Reminds you of your grandparents reminds you of a time when you were a child Well on that there's at least one study that looked at biologically meaningful odors modulating sleep So at least for babies it's being able to smell their mum reduced their crying induced feeding behaviors which

13:12Norman Swanyou know, could it then also accelerate them going to sleep? So while we're getting crazy with smells, what do we know about smells and dreams? So with dreams, mixed picture, some orders do affect REM sleep, but remarkably little, even intense orders do not seem to affect dreaming, but a very hard thing to study.

13:37Norman Swanso interesting. And there's even been research that's tried to look at kind of using the power of smell to do things like treat addiction. Yes, this is more psychological conditioning where you associate an awful smell with a behavior you're trying to break. And what's been shown in some psychological research is that the emotion you want to associate with the habit you want to break or not start is disgust.

14:04Norman Swandisgust is actually much more profoundly effective than fear. They've shown, for example, with kids. This is West Australian research, actually, which looked at what it takes to put kids off smoking. And it's not fear of lung cancer or things like that. So they developed ads, which, by the way, got banned because they were so effective.

14:29Norman SwanSo what do kids feel most disgusted about is the toilet. So somebody reaching into a toilet, pulling out a cigarette and lighting it. And then the other is taking a cigarette to the mouth and lighting it and it turns into a cockroach because kids eat cockroaches. So that's a sense of disgust. So people have used try to associate, say, for example, hydrogen sulfate rotten egg smells with smoking to try and condition you out of smoking. And it will work with some people, but it's whether it lasts or not is another issue.

14:59Tegan TaylorWell yeah, so they gave people the smell of cigarettes together with the smell of either rotten eggs or fish as people were sleeping. The idea that our brains are more malleable in sleep and at least in this study...

15:10Tegan Taylorthere was a reduction, a significant reduction in smoking following this conditioning during sleep. So maybe there is something there. Maybe there is. But do you want your brain messed around with while you're sleeping? I'm not so sure. I don't want to be in a lab with scientists waving smells under my nose as I'm sleeping. Well, okay. So we're maybe waking up in the middle of the night. We're maybe smelling either fish extract or lavender at random. Those aren't the only sleep tips we can give people, though, if they're looking for a good night's rest. People know the basics, which is dark room, no screens. Don't drink alcohol before you go to bed. Keep your caffeine away from, you know, probably the afternoon on. Don't eat too close to bed. Don't go exercising too close to bedtime. You can have a warm bath. But there are other things as well. We'll come back to that in other words. You're just throwing out these pearls of wisdom, Norman, as if everyone knows them. I think there's going to be some surprises in there. But sure, let's say that up for another time. Delore, thank you so much for the question and for the opportunity to talk about.

16:08Tegan Taylorour noses in sleep because it's been an absolute blast. And it's another example of our n equals one series, which is, you know, if you've got a favorite... Neuroscientist equals one. That's right. So if you've got a favorite n equals one using smells, orders, aromatherapy, send them in. We'd love to hear from you. That rash at abc.net.au. I would particularly love to read your weird sleep hacks. Tell us how you get back to sleep if you wake up in the middle of the night. Make it weirder than Bruno's one.

16:38Tegan TaylorWhat's in the mailbag? Well, there's an email here from Pamela in reference to our episode on body hair that we did a couple of weeks ago. Pamela says, as someone who lost all my body hair during chemotherapy, I have to concur with Teagan's alopecia-suffering friend. Without nasal hair, your nose drips frequently. It also takes a considerable amount of time for nasal hair to grow back and the dripping to stop.

17:02Tegan TaylorI'm two years post chemo for non-Hodgkin's lymphoma and it still happens. They're not as frequently. This is one of those things that nobody ever warns you about when you have chemo, possibly because it isn't discussed. The other panelist says is that you temporarily lose your fingerprints. I only found out because I have an older iPad which uses fingerprint recognition. Oh, so that's time to rob a bank. Right. Had you heard that before? No.

17:28Tegan TaylorMy gosh. Well, Pamela says, as a former nurse who worked in the radiotherapy and oncology department in Thomas' hospital London, I certainly didn't know. Thank you, Pamela. Fascinating. And long may you not need any more chemo. Indeed. Well, thanks for your emails. You can always send your emails to us that rash at abc.net.au. See you next week. See you then.