Chapter 1: Trendy self-care hacks
Hi I’m Wendy Zukerman and you’re listening to Science Vs. Today on the show we’re pitting facts against Self Care.
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The internet these days is littered with self-care hacks that promise to make you feel like a better you. People say that jumping into ice cold water makes them feel incredibly happy …
Cold plunges has caught on … From celebs to everyday athletes taking a dip into frigid water
Here we go!! Here we go!! Oh yeah
Don’t be a wimp
GET IN THE FUCKING COLD it’s great for everybody
AHHH
So that's cold plunge… but if you're not into that some people say that writing a gratitude journal is so powerful that it can rewire our brains ….
Gratitude will change your fucking life
I’ve said it and I’m going to say it again, gratitude is the attitude
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Today we are exploring the science behind some of the buzziest self care ideas…. and so - of course, for the show - I had to give them a go…
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- I jumped into cold water…
If I can make a sound effect for my legs right now, it would be blblblblb
I wrote a gratitude journal…
Ehhhh that's how I feel … omg it just feels icky!! to write a gratitude journal for my own self care… BLAAAHHHH
And found something about myself that I never ever expected…
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I actually feel so much better hahaha am I about to become a self care person?
When it comes to self-care there’s a lot of
<<get in the fucking cold>>
But then there’s science… Science Vs self care coming up after the break.
PRE ROLL
Chapter 2: Ice baths: How our body reacts
WZ: Welcome back. Today on the show, we are talking about self-care. Is there any science behind it? Michelle Dang, our producer here, has been looking into this. Hey, Michelle.
MD: Hey, Wendy. So, Wendy, are you into self care?
WZ: No, I am not into self care.
MD: That was a long pause.
WZ: It shouldn't be. No. I have made fun of self-care in private, but I've never actually looked into the science of it. And I will say that the past few months have been quite stressful for me - so I'd love some ways to not feel stressed …and feel better
MD: Are you ready?
WZ: I'm ready. I'm ready. So where do we begin?
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MD: All right, so the first one we're looking into today is ice baths. This trend actually involves all kinds of cold water stuff, including cold showers.
WZ: I'm really excited we're doing this. Cos they're ev, so here's what I have heard. They are amazing for your mind and your body. They just make you feel great! They can cure depression Everyone needs to be doing them. You're a wimp if you don't do it because the science is so clear on this. Get in the water. Basically, this is the vibe I'm hearing from the Internet.[1] So is it true?
MD: So I found the perfect person to dive into this. Her name is Heather Massey from the University of Portsmouth in the UK.[2]
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And you should know that Heather is not unfamiliar to cold herself.
HM So, yeah, I'm a cold water swimmer, so I have been in really quite chilly water. So the coldest water I've been in is water that is 0.2 degrees Celsius.
WZ: 0.2 degrees. Okay, So for our American friends, this is 32 degrees Fahrenheit[3] or just cold. That's really cold.
HM I wasn't in it for very long and I don't advise it.
MD: Yeah. So Heather was selected to represent Great Britain at the Ice Swimming World Championship and 2017.[4]
WZ: Ice swimming Championship. Oh, okay. So this this scientist likes cold water.
MD: She actually has a small pool in her lab[5] that makes things super cold - and she has people get into it - so she can see what happens to their body.
WZ: So what is she found in her? In her cool pool?
MD: Yeah. So Heather told me about what happens to your body once you get into that cold water. There are actually some reasons why it might give you a mood boost. So when you get into the cold water, your body gets this huge response called the cold shock response.
HM As soon as you get in, you feel a big an urge to take a big deep breath in. And then you get this rapid breathing response, a hyperventilation. It peaks after about the first 30 seconds, and we notice after that that it starts to wane. Now, it might take between 90 seconds to 3 minutes to pass. But alongside that change in your breathing, you're also going to experience changes in your blood pressure and also a big increase in your heart rate as well.[6]
WZ: Yeah, she describes it well. Right. You know, that feeling of, Oh, my God, oh my god, get out of the water? Right..
MD: So, you know that stimulation certainly wakes you up a bit, but it can also set off this whole hormonal cocktail that could make people feel a bit giddy.[7]
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MD Just like there was this study that had ten men sit in water that was about 14 degrees Celsius or 57 degrees Fahrenheit.
WZ Mm hmm.
MD And they had them sit there for an hour. And what they found was something kind of surprising. This cold water immersion actually boosted their dopamine levels in their blood. So, you know, dopamine - one of our feel good hormones.[8]
WZ: Right.
MD: And in this study, it actually went up by 250% compared to where they started
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WZ: Wow. Wow. That's for an hour just sitting in this cold, cold water.
MD: Which is quite a long time.
WZ: Yeahhhh
MD: They also found a boost in another chemical called noradrenaline. It went up by 530%. And when they checked their bloods an hour later – these chemicals had started to drop off – but they were still higher than before jumping into the cold.[9] Now this paper of 10 dudes gets talked about a lot in the ice bath world[10]– but don't know if everyone will get these huge spikes. Heather says there could be something here though...
HM So these are all hormones that have a big impact on our mood.[11] We also get big changes in brain blood flow as well, and different parts of the brain have different activity levels once you've been in the cold water.[12] So all of these things happening may be mood altering.
MD And we see other potential benefits too… like in the immune system - you can see upticks in certain immune markers like T cells and B cells[13] …
WZ Oh cool
MD So even though these changes are temporary. It's super interesting.
Chapter 3: Can cold plunges help with depression?
WZ: Yes. So changes in the blood of these important hormones, sounds promising, what do we know about how it affects our mood? There's all these claims out there that it makes us feel great and might help with depression?
MD: Yeah so… the current buzz is on ice baths and cold showers - we don’t have a lot of research there with mental health.[14][15] What we do have, though, are studies on cold water swimming. Like, Heather and her team did this one study where they looked at around 60 people who signed up for a ten week cold water swimming course. And what they did was compare their mood and well-being to their friends and family who sat on the beach.[16]
HM Don’t picture a Hawaiian sun with gorgeous white sandy beaches. … It was raining, it was quite windy. And so we we didn't actually think we would see many changes in people's mood and wellbeing
WZ:Ok what did they find?
MD What they found was that the swimmers did get a mood boost and that it was a bigger increase compared to those people who just chilled on the beach.[17]
HM: And when we surveyed them at the final survey point at the end of that last session, they was still very, very excited, very active, very engaged. So really a really positive experience for them.
MD: Now, other cold water swimming studies have found stuff like this too - that cold water swimming can make you feel less tense, and less stressed[18][19][20]
WZ: Aha. Uh huh. I guess I. I don't know. like those studies... I don't find that convincing to say that this can help people with their depression because someone who signs up for a cold water swimming study like A wants to get in the water and B, there's so many reasons why you might get a mood boost from being in this big group of people where you all want to jump in the water together and you're so proud of yourselves that you've done it and you've achieved something that to me, I'm not jumping to, ‘Oh, we have a cure for depression.’
MD: You totally hit the nail.[21] Heather says that all could be a part of this[22][23]
HM: you've developed a common interest with people. There's a social side to it.
MD So those are the cold water studies, and then – Heather did tell me about this interesting anecdote… Or I guess it was a case study where Heather's team worked with a woman who had really nasty depression[24]
HM: She was on a lot of medication for depression and she felt that it really wasn't working for her. So she did say she would try anything.
MD They had her try cold water swimming with a swim coach once or twice a week. And - it really seemed to make a difference …[25]
HM: Gradually over the course of that summer, she, in consultation with her doctor, reduced her her medication because her symptoms of depression had reduced. And by the end of the summer, she was not taking any medication for her depression
WZ Oh wow
MD: But that's of course just one person… …
WZ: If you want another anecdote - from another person – I have found that I do actually like jumping into cold water… do you?
MD: No, not at all.
WZ: I have access to an incredibly cold swimming pool. And I have been jumping into it and I really like it. And I get that that giddy feeling you were describing. But I will say that I have tried to get friends to to jump into the pool, too, who are going through like tough times. And I'm like, maybe it'll make you feel good. Like it makes me feel. And they'll just be like, Nope, absolutely not. Like, not interested. And it has made me wonder, like, do we have– cause a lot of the studies you've been talking about seem to be people who wanted to go into the water, but do we have studies like a randomized controlled studies where they've just like pulled people out and actually seen it gives mood boosts to everyone or, you know, many different kinds of people, not just those who are like, woo hoo, let's get in the water.
MD: Yeah. Yeah, I totally see your point. We don't have that evidence yet.
WZ: Right.
MD: But the science is headed there. So, you know, Heather is working on a randomized controlled trial right now.[26] And what they're doing is randomizing people with depression symptoms to take a cold water swimming course on top of their regular treatment. And she actually told me it's early, but they've already been seeing a benefit come through.
WZ: Oh.
MD: Though until we get more data, Heather's stamped on the point many times that we're not at the point where science can say that this works for everyone. And, you know, there are physiological reasons why it probably won't work for everyone.
Chapter 4: The risks of ice baths
WZ: Oh, what are they?
MD: It might actually be quite painful – for some people to do it.[27][28] where their nerves at the surface of the skin,[29] cold receptors, get more of a nasty jolt from the cold –
HM: basically you can imagine that it's like having lots of pins and needles and it's that painful for some people.[30]
WZ: Interesting. It's funny because I feel like the way that this is talked about online or even just like over beers is that if you're sensitive to the cold, that's a code word for you're a wimp. But actually there are physiological reasons why it's different for some people.
MD: Right.
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MD: And, you know, there's other possible bad stuff to you that people should watch out for before doing this. Like, there's this thing called non-freezing cold injury where you can actually get nerve or blood vessel damage from being too cold or wet for too long.[31] So Heather's seen it happen in friends who swim in icy water. And it can look pretty gnarly when it first happens …
HM it's pretty horrific their hand, their whole hand is swollen up. So it looks like a bit of a cartoon hand. So rather than, you know, the fingers got very, very puffy and very big and they could barely bend their fingers. They were in quite a lot of pain as a result of it as well.
MD: And sometimes - this pain can stick around - some people even get permanent damage.[32][33] Heather says what's also a bit yikesy about this is that it can be different from one person to the next. Because people's bodies get cold at different rates. So this means that the temperature or time that could give you this non freezing injury could be totally different for you than for me.[34][35]
HM: We don't know what the dose of cold is that's required. We don't know. It might be for some people that it could be a four minute ice bath. It could be in other people - it could be in 15 degree water.
MD: Yeah - that's 59 F[36]
WZ: Yeah. That's not that cold.
MD: Yeah.
WZ: It's. It's way. It's way warmer than an ice bath, that's for sure.
MD: [37] Also, you know, jumping into cold water can change your heart rate pretty rapidly. So it's not recommended for people with heart conditions.[38] to just plunge in there. So as for all this stuff on socials... that's like - GET IN THE WATER – Heather's like, hmm, that's not what the science says yet
HM: it's not an activity that we should prescribe to people. If people want to try it, then let them have the opportunity to try it. But it's not something we should say. It's worked for me, so it's going to work for you
And just one more quick thing - when you’re on tiktok you often hear this set of instructions to do 11 minutes a week
WZ: 11 minutes right? MD: Yeah 11 minutes but that comes from a study on brown fat and metabolism,[39] when it comes to mental health we don’t have any numbers like this yet.
WZ That makes sense, so if you want to give it a go be careful. What are we looking at next?
MD Yes get ready, Wendy, we are going to be looking into gratitude journaling
WZ Ugh I’m so skeptical of this, I have to say
MD Just give it a shot we’ll see
WZ: I'm ready.
BREAK
Chapter 5: Does gratitude journaling make us happier?
WZ: Welcome back. Today on the show, we are looking into the science of self-care. So far, Michelle Dang, our producer, has told us about the science of ice baths, which, although they feel nice for me, the science is pretty ehhhhh.
MD: Yes next up - we’re looking at gratitude journaling!
WZ: My biggest problem with journaling is why aren't we calling it writing a diary? Is that because that seems even more is that I had this whole theory that like the. Bro brofluence of the world didn't want to say they wrote a diary because it sounds like something a 13 year old girl does. So they were like, Oh, I journal, I journal. It's the same. Thing for all of us. Whether you put a little lock on it.
MD: Okay. Well, I guess there is a bit of a difference because you can write a diary about any old thing like the soggy muffin you had for breakfast or adorable dog that you saw in the park. Wendy.
WZ: Ugh
MD: Okay, maybe that wasn't for you, but that's not the type of journaling the Internet is really buzzing about right now. There's a bunch of hoopla over this particular kind of journaling. It's called gratitude journaling. And it's where you really focus on the things that you're grateful for.[40]
WZ: Hmm. Okay.
MD: Yeah. So Joel Wong, a psychologist from Indiana University Bloomington, told me that a big thing with gratitud-ing -
WZ: That's that's not a verb. I'll give you journaling. You can't have gratitud-ing
MD: No give me gratitud-ing, please.
MD: Okay, fine. Anyway, when you're writing these gratitude journals, Joel told me that the first thing you think about is what he calls the three A's. So - awareness.
JW Oh yeah, this thing is good.
MD And the second one.
JW There is appreciation, which is that you deepen your valuing of that goodness. It's like, Oh yeah, what is it good at? What's good about it?
MD And finally, there's attribution. So who did this good thing for me?[41]
WZ: A-ha. So instead of saying I. Appreciate this coffee that I'm drinking. You say, I appreciate the person who made this coffee. That right?
MD: Yes. You got this.
WZ: Okay. So does all this awareness, appreciation and attribution. Gonna make us happier? That's the claim right? That all this like gratitude. I was about to say, gratitud-ing - that all this gratitude journaling is going to make us happier. Does it?
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MD: So to find this out, several years ago, Joel did this study on gratitude letter writing. They looked at a group of people who were seeking therapy, and they mostly had like a mix of anxiety and depression. So Joel split these folks into different groups. Like in one group, they had them do three sessions of gratitude letter writing … basically a letter to someone they haven’t “properly thanked.” They telling them specific things that person has done for them and how it made them feel. Another group was a control that they were they didn't do any writing at all.[42]
WZ: Okay. So what did they find? Did it help?
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MD: Yes actually, the gratitude letters did help. At the start, they had evaluated everyone on this scale that’s used to measure depression. And after a month - the gratitude letter writers were doing better than the other people in the study.[43]
JW: Those who were in the gratitude condition had slightly better mental health compared to the others. And the interesting thing was that the effect grew even slightly larger at three months
MD: Yeah. When they checked in three months later, they saw that the effect was still there and had even grown a little bit.[44]
WZ: Really? That's.. that feels alarming. From just three sessions of gratitud-ing? What?
MD: Yeah. I mean, not every study finds this like others see the effects fade in a couple of weeks.[45] But there is one study that has found it can last up to six months.[46] And a recent meta analysis looked at around 25 studies on gratitude writing and says the evidence here suggests that writing messages of gratitude or gratitude journaling can increase happiness, at least temporarily.[47][48]
WZ: Ha. Wow. Okay, so how does it work?
MD: Ooh, yes.
Chapter 6: How does gratitude work?
JW But one of the more interesting findings was answering the question Why?
WZ Joel a man after my own heart. Why Why?
MD Yes haha. He's done one of the few studies to tackle this. So the one thing I haven't told you yet is that there was this other arm in the study that just did expressive writing, kind of like just writing a diary.
WZ: Okay, So soggy muffins and cute little dogs. Whatever.
MD: Well, they were asked specifically to write about stressful experiences.[49] And it didn’t work as well as gratitude letter writing.
WZ Oh. ok ok!
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MD: So he looked for clues as to why the gratitude journaling might have worked better. And he did this by digging into the kinds of emotional words that people were writing... They used computers to tally up the percentage of positive words people wrote, like love and happy - versus the negative words like sad and angry.[50]
WZ: Mm hmm.
MD: And what they found was that the gratitude group, it wasn't that they were writing more positive words. It's actually that they wrote less negative words.
JW So it's almost like it's the gratitude was shifting. I mean, it's a little bit speculatory, but it's almost like the gratitude letter writing was shifting people's attention away from the negative. In the expressive writing they were delving into the negative emotions. And that's not what I would have expected. I thought it would be like, you know, gratitude, boost the positive.
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WZ: Okay. So they were less negative, not more positive.
MD: Yes. So that's the crux here. It's like maybe what's making you happier is not trying to focus on being happy, but actually being less negative.[51]
WZ: Oh interesting
MD: It’s also linked with being more empathetic, and studies have shown it can change your relationships with people,[52][53] for example …
JW It sort of makes you less of a jerk.
MD Haha I see in plain words
JW One study found that people were practicing gratitude, generally they were less of a jerk at work.[54]
WZ: What? How do they know that?
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MD: So, Joel is, talking about a study that got 200 people from one company to gratitude journal for ten days, and then they asked coworkers to evaluate their jerk-ness by answering survey questions like how often in the last two weeks has your coworker criticized another coworker and how often has your coworker shot others out of the conversation? [55]
WZ Yeah, that’s jerky behavior
MD Then yeah they looked at what these coworkers had rated them, and ta-da…
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...gratitud-ing had reduced jerkiness.
JW What's fascinating is that research has also shown that gratitude extends beyond your original benefactor, to you want to be you want to do something good for other people, too.[56]
WZ: So once you open your worlds to the cheesiness of gratitude, you become more empathetic and less negative.
MD: Yes. And Joel says even spending just a little bit of time each day thinking about what you’re grateful for can help too.[57] So I thought maybe we should give. Give this all a shot.
WZ: What, You want us to write a gratitude journal?
MD: Yes, But I think we should take kind of like the bigger dose and write a gratitude letter.[58]
WZ: Uh huh. I mean, I've just had the science. I should be excited about this.
MD: You've got to do it for basically 20 minutes at a time and write to someone that you feel like you haven't thanked enough.
WZ: Like now? Like right now?
MD: Yes. And then make a little voice memo about how you feel. OK? So see you in 20 minutes.
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WZ bfff
MD Ok let’s start *click*
WZ This first one is to my mum. We’ll start simple Thank you. For all the times. You've cooked macaroni and meatballs
MD: Dear Mom. Thank you for everything. Haha, too cliche.
WZ Thank you for teaching me not to care what strangers think of me
MD: The pho that you cook is to die for
WZ making me know that I am loved
MD: For indulging in Costco pastries with me and always being down for ice cream
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WZ Gratitude letter done.
MD: I think it did put me in a good mood. It really distracted me from the things I was stressing out about. Made me feel like I am ready or want to do more for her
WZ: I think just going through all the lovely things that someone has done for me … just makes the work stuff not matter that much … and I feel better
WZ: Okay, hey Michelle
MD: Hey, welcome back
WZ: Thank you. Isn't that my line?
MD: Yes it was.
Chapter 7: When self-care isn’t just about yourself …
WZ: All right, all right, so you got me on gratitude journals - what's next? If you're about to ask me to, like, light some candles that have a manicure like this — we are done.
MD: Don't worry. Don't worry. Okay, so next we're going to jump into, you know, our last hack of the day.
WZ: Okay.
MD: And I thought it was interesting when putting together this episode, thinking about the term self-care, you know, usually think about stepping away, having some time to yourself, being on your own ...
WZ: Self. Self-care. Yes.
MD: But one thing that scientists are looking at is how much it can actually matter for us to be interacting with other people for our well-being.[59]
WZ Mm hm…
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MD: And, you know, there's all this talk that we're also in some kind of loneliness epidemic, particularly in the U.S... The U.S. surgeon general just this year has kind of raised this alarm.[60]
WZ: Mm hm…
MD: So to learn more about loneliness and what we can do about it for self-care, I talked to Juliana Schroeder.[61] She's a behavioral scientist from the Berkeley Haas School of Business, and she studies how people interact and perceive each other. And part of her interest in loneliness comes from this bummer of a time in her own life.
JS I felt like just unbearably lonely. I would be commuting in to work, like I felt as though I was just like, you know, floating outside the train, looking through the window at myself.
MD: So Juliana told me that in the U.S., this loneliness stuff is a real problem. Like one survey found, around a third of U.S. adults said they're experiencing loneliness almost all the time.[62][63]
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WZ: Oh, wow.
MD: And in that survey, over half of young adults and even mothers with young children reported, “miserable degrees of loneliness”
WZ: Miserable degrees of loneliness. They said that in the report?
MD: Yeah yeah
JS: And there's a lot of research that has shown that loneliness is associated not just with really bad mental health issues, but also with physical health concerns.[64]
MD: So, yeah, but there is this 2015 meta analysis[65] that gets pointed to a lot that found that loneliness is associated with dying earlier. And, you know, some of that might be because you don't have someone around to call a doctor, for example.
WZ: Right.
MD: You just don't have a social support network. But there's also just something about loneliness that is bad for our physical health and, of course, mental health.[66]
WZ: So.
MD: You know, how can we fix that?
WZ: Right. Can self care or social care do it?
MD: Yeah - it’s a great question. Cos in the research, we know that your friends and family are really important. Like, studies find that people who frequently hang out with friends and family report better mental health.[67]
WZ: Ok. Ok — but what if like you don't get along with your family, and you don't have a lot of friends… like then what do you do?
MD: Yes, so Juliana was like, hey – what about strangers – they’re all around us! What would happen if we just started talking to these strangers we're surrounded by?
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So back in 2010, Juliana started doing experiments to study just this. She kind of borrowed from her own life and set up these studies on trains…
WZ: uh huh …
MD: So in one study, they kind of scoped out a train station in Chicago and went up to people who were on their own. They recruited them for the study and…
JS: We randomly assigned people to connect with a stranger
WZ: Oh, wow. So they just took people on the train station and said, ‘Hey, you want to be involved in a study, go talk to that other person’
MD: So they didn't pair them up with people. They just set them off with a specific set of instructions, actually.[68] So they told them to find out something interesting about the stranger and to also tell them something about themselves. And told them that the longer the conversation, the better.
[MUSIC OUT]
WZ: Is this. Is this like your worst nightmare? Michelle?
MD: I would probably reject participating in the study. Be like ‘Sorry! I'm on my way. Got to go.’
WZ: Yes, Yes
MD Anyway, they also gave everyone an envelope with a post experiment survey to take with them.
WZ: Mhmm
MD: Here's what they found for the group that talk to the randos on the train.
WZ Mm hmm.
MD They ended up chatting for about 14 minutes on average[69] and…
JS People were reporting that they had a much pleasant, much more pleasant commute. It brought them more happiness, less sadness to have that conversation with the stranger.[70]
WZ: Huh? That's. That's very delightful.
MD: Yeah. Yeah, it. It felt good. They felt better than people in Juliana’s study who weren't chatty sallys - yknow just sat in silence. And this is kind of the opposite of what we expect. People imagine it would totally suck.[71] … me included … But for the people who actually went out and tried this, this isn't what happened.[72]
WZ: And so how much how much better did people feel? I can't imagine that this is some, like, blockbuster drug that Juliana has just created talking to strangers.
MD: Yeah. I asked Juliana how strong the results of these studies are. And it’s not huge, like in the studies it’s a small to medium effect.
WZ Okay
MD But you should know that Juliana and other other researchers have found similar results in different places like the they've done these kind of studies on more trains,[73] but also buses,[74] coffee shops,[75] waiting rooms.[76] And they find that people feel good after these conversations, whether they're short or long. [77]
WZ: So does Juliana do this more often now that she she's actually done the science on it?
MD: Yeah, actually, it wasn't until after the data came in that she started doing it herself.
JS And then I said, okay, like now I'm convinced I'm going to try it, you know, and I'm still kind of cautious, but I do I push myself now. Every time I'm in a context, I'm thinking, you know, I'm kind of bored or this just isn't that enjoyable. I'm like, okay, you know what? This is a perfect time to try out the research and to try talking to someone.
WZ: OK, ok! … So if we zoom out to everything we’ve talked about today - jumping into cold water, gratitude journals … chatting to random strangers … it’s looking like all this stuff actually could help us out - give you a little boost, a little mental boost, on potentially a kinda crappy day. Or on a good day! There is science on all this self care stuff that we can point to
MD: Do you think there’s anything you’re going to keep doing?
WZ: Yeah yeah! I actually do. I will be jumping into cold water more often. It will be something I think about when I'm stressed and overwhelmed, even just a cold shower. As I'm walking around in my day, I will be thinking about little moments that I could be having with strangers, just little moments just being mindful that like that can just be a little boost. So thanks, Michelle, this has been great.
MD: Thank you, Wendy. Thanks.
WZ: That’s Science Vs
CITATIONS
WZ My brain is pretty fried … I’m just a little overwhelmed. So I’m going to take a cold shower. <water> READYYYY … go! Ok … wah back! hahahah . OK but I am more alert. I actually feel much better. hahhaha Self care, am I actually about to become a self care person? Who am I?
CREDITS
This episode was produced by Michelle Dang, with help from Wendy Zukerman, Nick DelRose, Joel Werner, and Rose Rimler. We’re edited by Blythe Terrell. Fact checking by Carmen Drahl. Mix and sound design by Bumi Hidaka. Music written by Bobby Lord, Bumi Hidaka, Emma Munger, Peter Leonard, and So Wylie. Thanks to everyone we spoke to for this episode – especially Professor Megan Azad – thank you for sharing your self care story with us!! It was soo helpful! And special thanks to the Zukerman Family and Joseph Lavelle Wilson.
[1] E.g.
https://www.tiktok.com/@thats_just_jess/video/7216324229044686126
https://www.tiktok.com/@alwaysjalen/video/7254597910573190446
https://www.tiktok.com/@itsryanboswell/video/7184528372540771627
https://rvivl.co/why-ice-baths-should-be-your-next-self-care-ritual/
[3] (0.2°C × 9/5) + 32 = 32.36°F
[4] https://www.ice-swimming.com/results-world_championships2017.pdf
[5] https://www.port.ac.uk/about-us/our-facilities/lab-and-testing-facilities/extreme-environments-laboratories
[6] The cold-shock response subsides after 2-3 min and returns towards pre-immersion levels. The ventilatory response peaks within the first 30 s and declines to approximately twice pre-immersion levels by the third to fifth minute of immersion … The dynamic phase of the metabolic response is complete by approximately 3 min of immersion, at which time it has been reported to be 50% higher than pre-immersion values
The most dangerous response associated with CWI is ‘cold shock’.3 4 It is initiated by a rapid fall in skin temperature and includes gasping, hyperventilation, release of stress hormones, hypertension and arrhythmias.
[7] After CWI and cold-pressor tests, increased concentrations of dopamine (Šrámek et al. 2000), serotonin (Hirvonen et al. 2002) and β-endorphins (Suzuki et al. 2007) have been reported; these changes are associated with improved mood or the ‘post-swim high’
norepinephrine, also known as noradrenaline, is a neurotransmitter of the brain that plays an essential role in the regulation of arousal, attention, cognitive function, and stress reactions. It also functions as a hormone peripherally as part of the sympathetic nervous system in the “fight or flight” response.
[9] Figure 5 doi.org/10.1007/s004210050065 . Plasma noradrenaline and dopamine concentrations were increased by 530% and by 250% respectively
[10] E.g.
https://www.tiktok.com/@iceman_hof/video/7244186448788868379
https://www.tiktok.com/@interestingtopics101/video/7217535482400525573
https://www.tiktok.com/@polar_recovery_tubs/video/7233463902862920986
https://www.tiktok.com/@coldplungecam/video/7141386190485343531
[11] The known increases in plasma noradrenaline, beta-endorphin and synaptic release of noradrenaline in the brain due to stress induced by CWI, may therefore have a positive effect on mental health and brain development [Citation92].
[12] Thirty-three healthy adults naïve to cold-water swimming (age range 20–45, 16 females) undertook a 20 °C 5 min whole-body bath. We measured brain connectivity and self-reported emotional state before and after cold-water immersion. Our findings showed that participants felt more active, alert, attentive, proud, and inspired and less distressed and nervous after having a cold-water bath. The changes in positive emotions were associated with the coupling between brain areas involved in attention control, emotion, and self-regulation. A reduction in negative emotions did not show strong associations with changes in brain connectivity. The results indicate that short-term whole-body cold-water immersion may have integrative effects on brain functioning, contributing to the reported improvement in mood.
[13] There are several studies, which have investigated how the immune system responds to regular non-infectious stress stimuli after CWI. For example, in one study [Citation81] involving 6 weeks of regular 1 hour CWI (14°C), increases in plasma concentration of interleukin (IL)-6, total T lymphocytes (CD3), T helper cells (CD4), T suppressor cells (CD8), activated T and B lymphocytes (HLA-DR) were found. … In another study, which compared habitual and inexperienced winter swimmers, the authors reported significantly higher concentrations of plasma IL-6, leukocytes and monocytes in winter swimmers compared to inexperienced subjects.
CWI causes the release of stress hormones (Johnson et al. 1977; Kauppinen et al. 1989), and Dhabhar (2014) argues that short-term stress readies the immune system to deal with injury or infection. Research into the effects of CWI on immune function has produced mixed results … In addition, different leucocytes and immunoglobulins (Igs) have been measured. Furthermore, changes in immune system markers may not translate into altered in vivo defence (Castellani et al. 2002), and very few studies asked participants to report real illness.
[14] However, although controlled trials investigating the therapeutic use of CWI are lacking, there is a theoretical, physiological basis suggesting that this is an area worthy of investigation
[15] One paper on cold shower and depression: Shevchuk 2008 hypothesis paper (3 participants, including self) The proposed method of cold hydrotherapy appears to be effective at alleviating depressive symptoms in approximately two years of experience of the author and two people that he knows (longer experience for them). This is a statistically insignificant sample given that there was no questionnaires, no systematic records, no consistent methodology, and this was not a volunteer study
[16] Feasibility study 2020: Profile of Mood States and Short Warwick–Edinburgh Mental Well-being Scale questionnaires were completed by participants on a 10-week introductory outdoor swimming course (61 swimmers) and 22 controls who sat on the beach.
[17] Feasibility study 2020:It was demonstrated in swimmers that there was an acute reduction in negative mood states (tension, fatigue, depression, anger and confusion) and increase in positive mood (esteem-related affect and vigour) during the pool and outdoor swimming sessions. … Furthermore, over the course of the 10-week programme, a chronic reduction in negative mood was found in the swimmers, whereas positive mood remained at moderate to high levels. There were also increased well-being scores in swimmers particularly during the sea swimming phase of the study.
[18] Forty-nine voluntary Finnish winter swimmers and 33 non-swimmers from the Finnish city of Kajaani participated in the study. … Tension, fatigue, memory and mood negative state points in the swimmers significantly decreased with the duration of the swimming period. After four months, the swimmers felt themselves to be more energetic, active and brisk than the controls.
[19] 228 people, between 19 and 88 years, including 107 winter sea bathers and 121 controls. … Winter sea bathing was associated with lower levels of self-reported stress and higher wellbeing.
[20] In this study, participants reported better mood but there was no difference to the control: Their experience was that the swimming had relieved physical symptoms and made their mood more positive. However, we found no major differences between winter swimmers and controls in any CCEI or TAS variables.
[21] However, as mentioned in the introduction and based on the results from this review, many of the health benefits claimed from regular cold exposure may not be causal and may, instead, be explained by other factors including an active lifestyle, trained stress handling, social interactions, as well as a positive mindset.
[22] though the study provides no mechanisms for the changes in mood or well-being, swimmers explained the positive effects of performing an exercise they came to enjoy. This included being in cold water, in an outdoor space with few people around, provided an opportunity for mastery, goal achievement, confidence building, challenge and a sociable environment with like-minded people. … It may also be that a number of these factors are interlinked. Previous research indicates that physical activity in natural environments is associated with a reduced risk of mental ill health,9 and further to that, may have a positive therapeutic effect.
[23] This study tried to control for effects of swimming - however was also outdoors and with a group, not randomized: “The cold-water immersion group showed a significant decrease, with a large effect size, of 15 points from 51 to 36, compared to 2 points in the control group, 42 to 40.” … “Although this study has focused on the effects of cold-water immersion in a natural environment, there may well be other factors that are responsible for the changes in mood. These include the social aspects of the group, or the general effect of nature, and the dose of CWI received. “ Single immersion ~20min
[24] Case study 2018: A programme of weekly open (cold) water swimming was trialled. This led to an immediate improvement in mood following each swim and a sustained and gradual reduction in symptoms of depression, and consequently a reduction in, and then cessation of, medication. On follow-up a year later, she remains medication-free. … Within a month of open water swimming, she was able to reduce her medication and no longer required drug treatment after 4 months.
[25] She undertook regular (once to twice a week) accompanied open water swimming between the months of April and September. … Within a month of open water swimming, she was able to reduce her medication and no longer required drug treatment after 4 months.
[27] Extreme cold is experienced as pain because cold is a noxious stimulus that causes profound, irreversible tissue damage at temperatures above and below freezing (Viana and Voets, 2019). In healthy individuals, the temperature at which skin cooling begins to evoke pain and subsequent protective behaviour is about 20 °C, minimizing exposure to dangerously cold stimuli. Among the most unpleasant symptoms of people suffering from chronic pain, however, is cold allodynia, when cooling to normally innocuous temperatures is experienced as excruciating pain
[28] Cold intolerance has been defined as a set of symptoms including pain, tingling, numbness, chills, stiffness, weakness, swelling or skin color changes on exposure to cold. … the literature on the prevalence of cold intolerance in the general population is scarce (See Introduction and Discussion on previous research)
[29] Cold sensing depends on peripheral input from specialized sensory neurons that detect drops in temperature through cutaneous nerve endings. … Activation of these ion channels by cooling leads to membrane depolarization, action potential firing, and ultimately the perception of cold by the nervous system (Palkar et al., 2015).
[30] Ion channels expressed in peripheral cold-sensing neurons transduce cold stimuli. … In healthy individuals, the temperature at which skin cooling begins to evoke pain and subsequent protective behaviour is about 20 °C, minimizing exposure to dangerously cold stimuli. Among the most unpleasant symptoms of people suffering from chronic pain, however, is cold allodynia, when cooling to normally innocuous temperatures is experienced as excruciating pain … The psychophysical threshold for cooling perception in healthy humans is a drop of just 1–2 °C, with cold pain perceived below about 20 °C, and a distinct stinging cold sensation felt at subzero temperatures (Jensen and Finnerup, 2014). Despite inter-individual variability, these values generally do map onto sensory afferent cold thresholds.
[31] NFCI itself could be a neurovascular injury with a primary nerve injury affecting vascular function, or a vascular injury causing nerve damage, or purely neural in some cases and vascular in others. Different individuals may be susceptible to either or both pathologies.
[32] n=26 naval soldiers Although large-and small fibre neuropathy may be restored following cold injury, there is a risk of a permanent and disabling cold hypersensitivity, corresponding to the findings of cold allodynia.
[33] In stage 3, the tissue becomes swollen, red and hot and the associated pain may be persistent and severe; this hyperaemic stage may last for up to 4 weeks in severe cases. Stage 4 is the chronic state, which may last for many years and is characterised (in variable combination and severity) by cold sensitivity, numbness, hyperhidrosis and persistent, intractable pain
[34] We know that exposure to cold and wet conditions can result in NFCI, but have no idea of the exact dose required to cause it. … Interindividual variation was observed in all of the groups for every variable measured, making a clinical diagnostic cut-off for NFCI problematic … Alternatively, the type of cold exposure (e.g., intensity, duration, wettedness, static/dynamic, etc.), coincident factors (e.g., stress, dehydration, deep body temperature, age, sex hormones, genetic predisposition) and comorbidities (e.g., peripheral vascular disease) may result in one form of NFCI pathology or another (Tipton et al., 2020)
[35] Another issue is that it’s not known how cold is too cold when it comes to cold water immersion and non-freezing cold injury. There are also a lot of differences in the way our individual bodies respond to cooling. For example, those from African and Caribbean backgrounds seem to be more susceptible to non-freezing cold injury – so the risks from cold exposure will vary between different people.
[36] NFCI may be prevented by limiting exposureto cold and maintaining adequateperipheral blood flow. This may be difficult insome diving scenarios. During scientificstudies at the Institute of Naval Medicine inthe United Kingdom, the medical withdrawalcriteria used to avoid NFCI during experimentsin the cold is a local temperature of8°C for 15 min or 6°C at any time. During longduration exposure to cold, subjects are withdrawnand slowly rewarmed if any skin temperature falls below 15°C (59°F) for more than 12 hours.
[37] It is thought that exposure to temperatures below 15°C are needed for NFCIs to develop4,37 (though similar injuries may occur at warmer temperatures).
[38] The loss of control of breathing can be a precursor to drowning, and the increased work required of the heart and circulation can result in cardiovascular pathologies. Cardiac arrhythmias are particularly common if cold immersion includes the face, breath holding and coactivation of the cold shock (sympathetic autonomic nervous system response) and diving response (parasympathetic autonomic nervous system response)—a combination of conflicting inputs to the heart termed ‘autonomic conflict’.4
[40] E.g.
https://www.tiktok.com/@emilieleyes.hypnosis/video/7191947140057419050
https://www.tiktok.com/@davidmeltzer/video/7134371866524929326
https://www.tiktok.com/@florencegiven/video/7201821510900796678
https://tiktok.com/@paynelessflipping/video/7261620568447880490
https://www.tiktok.com/@katierynn/video/7148946118758403374
[41] From Joel’s Review paper: Following Emmons and Stern (2013), gratitude is defined as the appreciation of goodness in one’s life and acknowledgment that the sources of one’s benefits reside partially outside oneself (e.g., family members, friends, one’s community, and/or God). Put differently, gratitude is a social virtue in which people appreciate the benefits they receive from their benefactors (Emmons & Mishra, 2011). I further define gratitude experiences as those that include gratitude emotions, cognitions, and disclosures (e.g., sharing with a friend what one wrote in a gratitude journal) as well as expressing, receiving, witnessing, and responding to interpersonal gratitude.
[42] Joel’s study: Participants were 293 adults seeking university-based psychotherapy services. Participants were randomly assigned to one of three conditions: (a) control (psychotherapy only), (b) a psychotherapy plus expressive writing, and (c) a psychotherapy plus gratitude writing.
[43] Joel’s study: About 4 weeks as well as 12 weeks after the conclusion of the writing intervention, participants in the gratitude condition reported significantly better mental health than those in the expressive and control conditions, whereas those in the expressive and control conditions did not differ significantly.
[44] Joel’s study: One interesting finding is that the benefits derived from the gratitude intervention gradually accrued over time. Although there were no significant differences in mental health outcomes at Time 2, gratitude clients reported better mental health than those in the other two conditions 4 weeks after the writing interventions at Time 3 (d = 0.22), and this difference peaked at Time 4, 12 weeks after the writing interventions (d = 0.30).
[45] Positive affect increased in an RCT with a gratitude and active control intervention, and a control group (Ouweneel et al., 2014; Wolfe & Patterson, 2017). However, positive affect decreased to baseline level 2 weeks after the intervention while participants from the kindness intervention group reported higher positive affect at that point of time (Ouweneel et al., 2014).
[46] The results of this study suggest that a 6-week gratitude intervention is an effective, low-intensity intervention for enhancing mental well-being but not distress among people with low to moderate levels of well-being and moderate distress, at least in higher-educated women. The sustained effects on various measures of gratitude up to 6 months follow-up suggest that it is possible to promote a lasting appreciative perspective on life. … Effect sizes at 6-months follow-up were d = .31 for mental well-being (95% CI = − .12–.73) and d = .17 for appreciation of simple pleasure (95% CI = − .26–.60).
[47] A systematic review of the strength of evidence for the most commonly recommended happiness strategies in mainstream media:
Two sufficiently powered, pre-registered studies suggest that writ- ing messages of gratitude provides a short-term increase in PA. Other well-powered studies suggest that writing gratitude letters may be a hit-or-miss strategy for increasing happiness, but we found consistent evidence that people in diverse cultural contexts benefit from making gratitude lists. Taken together, there is reasonably solid evidence that gratitude practices can increase mood, at least temporarily.
[48] Under Emotional well-being: Taken together, although not all studies have yielded positive results, the vast majority of research shows measures of emotional well-being to increase with small to moderate positive effects in response to a variety of gratitude interventions administered in a variety of populations, or to maintain at a certain level and prevent emotion well-being from declining.
[49] Participants were instructed to write about the most stressful and upsetting experiences of their lives for all three sessions. Participants in the control group did not complete any writing assignments.
[50] We focused on the percentage of positive emotion (e.g. love, happy), negative emotion (e.g. sad, angry), and we words (e.g. we, our) in participants’ writing samples across all writing sessions in the gratitude and expressive writing conditions
[51] Nonetheless, the reduced use of negative emotion words was the only linguistic dimension that predicted better mental health at Time 4 and the only mediator of differences in mental health between participants in the gratitude and expressive writing conditions. As theorized by Emmons and Mishra (2011), by focusing on the positive qualities of one’s benefactor, gratitude might help to reduce toxic emotions, such as resentment and envy, which in turn promotes better mental health.
[52] Work by DeWall et al. (2012) and Deng et al. (2018)further establishes gratitude as a social and moral emotion and being able to empathize with others may prevent grateful individuals from acting in an aggressive way (García-Sancho, Salguero, & Fernández-Berrocal, 2014). Lastly, DeWall et al. (2012) investigated whether empathy mediates the negative association between gratitude and aggression and discovered that grateful individuals are in part less aggressive because of their higher empathy for others.
[53] The majority of the reviewed studies, both prospective and experimental, suggest that gratitude plays a role in maintaining healthy relationships, as well as in facilitating the formation of new relationships. Experimental and observational work suggests that gratitude increases prosocial behaviour, not just towards the benefactor but also towards others.
The following week, we invited participants’ coworkers to complete a survey reporting on the employee’s uncivil behavior over the last 2 weeks (ensuring the time reference of incivility was not before the mediating mechanisms). … Results revealed that the indirect effects were significantly different from zero at higher levels of perceived gratitude norms for all three outcomes but not at lower levels of perceived gratitude norms (see Table 6).
"We used a panel management company (ROI Rocket, Denver, CO) to recruit participants.
Study 1: 147 employees. Participants were randomly assigned to one of two experimental conditions.
How often in the last 2 weeks has your coworker put down others or been condescending to others in some way?
Study 2: 204 employees . Again, participants were randomly assigned to one of two experimental conditions, which were identical to those used in Study 1
(GOSSIP): How often in the last 2 weeks has your coworker criticized a coworker while talking to another work colleague?”
(OSTRACISM): “How often in the last 2 weeks has your coworker shut others out of the conversation?”
Supplemental materials: Figure S1 (Study 1) Assigned to gratitude condition - Analyzed (n=88)
Figure S2 (Study 2) Assigned to gratitude condition - Analyzed (n=112)
[56] More recent work has focused on prosocial emotions, specifically gratitude, as the primary mechanism driving generalized reciprocity (Baker and Bulkley 2014; Bartlett and DeSteno 2006; DeSteno et al. 2010). That is, the gratitude one experiences as a result of receiving help from another leads one to help a third person in need.
We identified 252 effect sizes from 91 studies across 65 papers-(Total N = 18,342 participants). The present meta-analysis revealed a statistically significant, and moderate positive correlation between gratitude and prosociality (r = .374)
[58] Finally, relative to the other gratitude conditions, participants who wrote gratitude letters to particular individuals in their lives not only showed stronger feelings of gratitude, elevation, and other positive emotions but also reported feeling more indebted. This study demonstrates that not only does gratitude “work” to boost well-being relative to an active neutral activity, but that some forms of gratitude may be more effective than others.
[59] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9560615/
[60] New Surgeon General Advisory Raises Alarm about the Devastating Impact of the Epidemic of Loneliness and Isolation in the United States
[62] US Surgeon General report: Recent surveys have found that approximately half of U.S. adults report experiencing loneliness, with some of the highest rates among young adults.
Cited:
Cigna 2021 survey report: Now, according to new, confirmatory data from Morning Consult commissioned by Cigna, more than half of U.S. adults (58%) are considered lonely. This is fairly consistent with pre-pandemic research that showed 61% of adults experiencing loneliness in 2019, after a seven percentage point increase from 2018.
[63] Harvard Making Common Caring survey: According to our recent national survey of approximately 950 Americans, 36% of respondents reported feeling lonely “frequently” or “almost all the time or all
the time” in the prior four weeks. A startling 61% of young people aged 18-25 and 51% of mothers
with young children reported these miserable degrees of loneliness.
[64] US Surgeon General report: Chapter 2: Individual Health
[65] The included studies provided quantitative data on mortality as affected by loneliness, social isolation, or living alone. Across studies in which several possible confounds were statistically controlled for, the weighted average effect sizes were as follows: social isolation odds ratio (OR) = 1.29, loneliness OR = 1.26, and living alone OR = 1.32, corresponding to an average of 29%, 26%, and 32% increased likelihood of mortality, respectively
[66] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6125010/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9560615/
[67] In terms of the source of social support, five studies out of seven studies (5/7=71.4%) concluded that social support from friends was equally important in terms of predicting depression as family support … while two studies (2/7=28.6%) reported that only family support exerted a significant influence on depression
The results showed that (1) the order of contact frequency and mutual support followed a hierarchical order from spouse, children, to friends; (2) zero-order correlations of both family support and friend support were associated with more positive affect and less negative affect
This feeling of being supported is related to lower levels of mental health problems and therefore acts as a protective factor against depression … Our results revealed that social support from family and friends are predictors of depressive symptoms and significantly negatively correlated with depressive symptoms as per the previous findings in the literature
[68] The research assistants recruited people walking alone to the train platform in order to make it easier for participants in the connection condition … Participants in the connection condition were told, “Please have a conversation with a new person on the train today. Try to make a connection. Find out something interesting about him or her and tell them something about you. The longer the conversation, the better.” … Participants in the solitude condition were told, “Please keep to yourself and enjoy your solitude on the train today. Take this time to sit alone with your thoughts. Your goal is to focus on yourself and the day ahead of you.” … open the envelope and complete the survey at the end of their train ride and mail it back.
[69] Additional survey results showed that participants in the connection condition talked for an average of 14.2 min (SD 11.3 min), had quite pleasant conversations overall (M 5.1, SD 0.9), and reported a positive impression of their partner (M 2.2, SD 1.1)
[70] Talking to a stranger on the train was not systematically unpleasant. In fact, participants in the connection condition reported having the most positive experience out of all three of our experimental conditions (see Figure 1). Most important, participants in the connection condition reported having a significantly more positive experience than participants in the solitude condition, t(94) 2.49, p .02, d 0.63.2
[71] Commuters predicted precisely the opposite pattern of the actual experiences observed in Experiment 1a, F(1, 64) 4.69, p .03, 2 0.07, not simply mispredicting the magnitude of these experiences but mispredicting their relative valence. … In particular, Figure 1 shows that commuters predicted that they would have a significantly less positive commute in the connection condition than in both the solitude condition, t(64) 2.46, p .02, d 0.41, and the control condition, t(64) 2.18, p .03, d 0.45…. Not only did participants expect to have the least positive commute in the connection condition, they also expected to have the least productive commute F(1, 64) 20.69, p .01, 2 0.24. P
[72] Experiments 1a and 1b Figure 1
[73] 2022 Juliana’s Study: Extending these prior results, in a field experiment with London-area train commuters, … Specifically, participants reported having a significantly more positive commute in the conversation condition (M = 0.89, SD = 0.98) than in either the solitude condition (M = 0.35, SD = 0.97), t(263) = 4.44, p < .001, d = 0.55, or the control condition (M = 0.41, SD = 0.91), t(243) = 3.92, p < .001, d = 0.50
[74] Bus: Study 2 (N=265) provided experimental evidence that commuters who greeted, thanked, or expressed good wishes to shuttle drivers experienced greater momentary positive afect than those who did not speak with drivers.
[75] Coffee Shop: In the current study, people who had a social interaction with a barista (i.e., smiled, made eye contact, and had a brief conversation) experienced more positive affect than people who were as efficient as possible.
[76] Juliana’s 2014 study: Experiment 5: To measure evaluations from both members of the conversation dyad and also to make people feel that they had free choice to talk (instead of feeling required), we created a situation resembling a waiting room at, say, the dentist. … Positivity. As shown in Figure 3, participants had a more positive experience when they connected with each other than when they avoided each other, regardless of the other experimental conditions
[77] Experiment 5 In a lab study with American university students48, participants spent 30 min talking to a fellow student, or they were allowed to choose how much of this period to spend talking and how much to spend sitting quietly, with nothing to do (n per condition ≈ 100). The students assigned to spend the whole time talking reported enjoying the experience significantly more than those who were able to spend part of the period in solitude (d = 1.08).