Posts in Health (6 found)
ava's blog 3 days ago

a week without caffeine

I've recently decided to stop drinking anything caffeinated for a month. My top offender has been matcha, which has a surprisingly high caffeine content depending on the kind and the amount you consume. Second is other green tea, and black tea. Third is the occasional coffee I get elsewhere, or flavored cubes to dissolve in water that contain caffeine. I don't consume soda or energy drinks, and I don't have coffee or a coffee machine at home. This comes after at least half a year of intentional use, or sometimes abuse, of it. I made no secret on this blog that 2025 felt like two years in one , and I achieved a lot - but I also used caffeine to push my limits in ways that weren't good. I wanted to feel normal and not limited by my illnesses, poor sleep, or anything really. So instead of just drinking maybe once a day for the flavor, I started drinking for the effect, too, making the teas stronger. So it slowly became more cups a day, and consumed later in the day. I often used it to be able to make it through 2-4 hours of university Zoom sessions or a workout, or to try and fight the fatigue from my illnesses, or to make up for a night of bad sleep due to pain, or staying up late with friends playing games until past midnight. I've just been feeling really burnt out in the last month of 2025, and I thought about what I could do to change that. I chose to take younger me’s advice: Years ago, I barely drank black tea every couple months, matcha maybe once a week or less, and no coffee at all. I only drank for the taste. I didn’t even know the stuff I was drinking had any significant caffeine, and I made it mild enough. I never wanted to become a person that relies on caffeine or uses it to push across limits . I looked at people who felt burnt out and thought: “ Yeah, if I used substances to quiet my body telling me it needs rest or food or whatever constantly for months or years, I would feel burnt out too. I would at least lay off the caffeine and heed the signals to help myself get out of that. ” Now I’m the one feeling burnt out, and I did use caffeinated drinks to push myself further than I should have! Younger me was right, and by using my favorite little comfort drinks that way, I just borrowed from the future every time. That’s energy that will be missing the next few days, weeks, months… unless I do the same again, but maybe with more caffeine this time. But I don’t wanna dig myself that hole. Shortly after NYE, I managed to drink two very huge cups of matcha, one big cup of strong black tea, a normal-sized cup of coffee, and then some more matcha again at a friend's house to keep me awake for a board game evening late into the night, and it was horrible. I didn't wanna treat myself this way. So going forward, I will need to respect my limits. I don’t further wanna normalize ignoring my needs like this for productivity. If it protects my well-being long-term, I will just study 2 hours less, or I can’t study that day at all, or arrive at work an hour later, or can’t participate in a game night until 2am. Of course it will suck sometimes, because abusing it intentionally made me feel more capable and enabled a truly busy year; but I’ll just have to accept it. In the end, I’m not opposed to resorting to it for important stuff (a deadline, complex work...), but not constantly. A week has now passed ( 23 days left to go ) of consuming no caffeine (and not even decaf, because that still contains some), and I wanted to give a first update on my experience! Headaches starting past 3pm and went on until I had to sleep; took an aspirin to help it. Had a bit of nausea too, felt brainfogged, but calm. The headaches feel like my exercise headaches, which makes sense, considering both a lack of caffeine and intense exercise expand the blood vessels in the brain. I didn’t think I would be affected like this, and I should probably have tapered instead of going cold turkey. First day back in the office after the holidays. I notice a bit of a headache again past 8am, but they went away after 10am or so; didn’t even notice exactly when it got better. I feel a difference in how I focus and work. Caffeinated drinks immediately create more energy and a drive to work on something big/demanding for me, but if the work is not enough to fulfill that desire (mundane, repetitive and small), I’d struggle to get myself started or work on it uninterrupted. I’d take more frequent breaks to check stuff on my phone, I’d play music or YouTube videos to keep that eager part of my brain busy enough to get the boring work done. It seems like the caffeine boost made me more dopamine-seeking. I was craving anything that would fully utilize me mentally and then searching for a replacement when that didn’t happen. Now without the caffeine, there is no intense energy spike or crash, no frantic seeking of more intense work that would make me a bit anxious, and no search for something that soothes and distracts me from that sensation. Instead, I was able to continuously work without much breaks, distraction or distress for hours. It was easier for me to focus, to get into the zone, in a sort of flow state, even without music or videos. While I am still bored of my current repetitive work, I felt better equipped to deal with that, as I had no strong urge for a challenge inside of me that’d make me uncomfortable if I couldn’t find one. My focus and motivation felt more sustainable and persistent, instead of coming in short, intense bursts. I felt happy for no specific reason during my lunch walk, which was a nice change from the overwhelm and feeling of being hunted that I got so used to. Had some intense headaches again in the late evening; I think I am more sensitive to very bright screen light, because it always starts when I boot up Hello Kitty Island Adventure on the TV, and I’m currently in a very bright area. Very brief headache this morning in the tram that didn’t come back, not even in the evening. I may have put the worst behind me. I notice I am less sensitive to my environment; the glaring lights, the tram sounds and people. I’m still a bit sensitive in general aside from caffeine or not, but it doesn’t feel heightened. I sit there present, aware, no noise cancelling, and feel… content. At work, I feel like I have more… time? To arrive, to slowly get started in my own pace, and as said in the previous day, keep a comfortable momentum. I’m not suddenly extremely “on”, feeling rushed by the caffeine buzz. I like this. I also feel like I’m more comfortable with switching tasks than I’ve been the last few months. I’m also more comfortable with rest and intentional boredom. I felt very very tired close before 10am, but made a great recovery somehow that kept me going until 10pm without feeling exhausted or fatigued in between. The caffeine withdrawal headaches and light sensitivity seem to be gone for good. What remains is craving the reward, the treat; those were my comfort drinks, irrespective of their caffeine content, but that maybe that also played a role chemically. I miss it for a sort of mental relief. I notice effects on my hunger! It feels more controlled, and less urgent. There is less food noise in my head. It could be that increased stress and anxiety that were exacerbated by caffeine raised cortisol and made me hungrier, or smaller/skipped meals via caffeine lowering appetite makes the hunger return with a vengeance later. Or I seek to comfort and soothe myself after becoming frustrated of not finding mentally stimulating work while on caffeine, and I crave food for that. I underestimated how much it really affected my mood and anxiety. Everything feels calmer and more manageable now, and I no longer feel like I am constantly drowning. Rest feels truly restful. I blamed it on some challenges and problems in my life, but I guess a lot of it really was the caffeine, and I didn't notice how truly bad the baseline anxiety had gotten. On the first day, I even said to people that it doesn't make me anxious. I guess it did, though. What still remains is the need for reward I talked about, and seeking comfort, knowing it would brighten up my day a little. I want to work on some non-work things that are a bit demanding, each in different ways (a secret blog project, job applications, studying for my exams in March, translating for GDPRhub...) and it would be great right now to borrow a bit of drive and alertness on what feels like the click of a button. I wanna rip myself from the afternoon drowsiness, but I have to do it "on my own" right now. I really have to make sure to drink enough without my go-to choices. It's getting harder to do so when I can't drink the stuff I love or even crave! I have to be more intentional about drinking enough, when it hasn't been a problem before. For when I continue in 23 days! Reply via email Published 11 Jan, 2026 I will reserve caffeinated drinks for when it really matters (harder, more complex and important tasks; not just because, and not to keep up with people). If the task is not later in the day, it’s preferable to not consume any caffeine after noon. I will make/order the drinks to have a lot less caffeine. I will keep in mind that appetite suppressed or lowered by caffeine means more ferocious hunger comes later, so I have to feed myself well regardless.

go Go Health Wellness Lifestyle
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annie's blog 1 months ago

Do you want to read a detailed post about eyelid surgery? Here it is. With photos.

I find this sort of thing fascinating. I looked for detailed info before my own surgery because I like to know what I’m getting into. If you’re grossed out by surgical/medical descriptions or photos, skip this one. So I had this spot — like a pimple or small wart — appear under my right eye years ago. 2017, 2018? Sometime in there. It was very small, directly under/partially on the lash line near the inside corner of my right eye. Not really noticeable, didn’t hurt or itch or grow or change so I didn’t worry about it 1 . Anyway over the last year it got a bit bigger, so I had it checked out. My dermatologist did a biopsy. Result: basal cell carcinoma. So I needed to have the spot removed. Due to its location, it was likely the lid margin 2 would be affected. So after the removal, I’d need eyelid reconstruction surgery by an ophthalmic surgeon. Here’s how they do it: They schedule the Mohs surgeries 3 in the morning. They schedule the reconstruction surgeries the same afternoon. They do this because Mohs surgeries can take… hours. They don’t know till they’re doing it. The surgeon takes off the cancerous area and a layer of the skin around it, then examines it under a microscope. If they still see carcinoma cells 4 , they take off another layer. Inspect the removed layer. Repeat until there are no carcinoma cells visible in the removed layer. The removal is quick. The inspection takes longer. So each “layer” (removal + inspection) can be over an hour. Once that’s done, they either sew you up there or send you off for reconstruction surgery. I was at the hospital from 7am to 5pm. Most of that time was spent waiting. The Mohs surgery required two layers removed. I was done there around 9:30. They bandaged my eye and sent me off for reconstruction which was scheduled for…. 2:30pm. So, yeah, lots of waiting. Mohs surgery Local anesthetic (needle in the cheek below the right eyelid). They lean you back in a chair and tuck surgical drapes around the area. Assisting docs hold the head still and hold the eyelid open or closed or whatever it needs to be. It’s pretty surreal to see a scalpel coming directly toward your eyeball. But the most surreal part was hearing the snip-snip-snip of scissors knowing it’s my skin  that’s being snipped off my face . Pain: none. They gave me another shot of anesthetic right before they patched me up which was nice. Hungry (no eating allowed before the reconstruction surgery). Did some Christmas shopping. Pirate impressions. Thought about food. Went to the bathroom a couple of times to peek under the bandage and make sure my eye was still there. Then the anesthetic wore off so I didn’t need to do that anymore. Contemplated the hierarchy of snacks. Assured 4 different nurses that there is zero possibility of pregnancy, no really, I promise, I do not have a uterus . Speaking of the beast (not) in me: Watched a couple of episodes of The Beast In Me . Looked at the entire Internet. Thought about food some more. Napped a little. Eyelid reconstruction Sedation (via IV) plus local anesthetic. I was very relaxed and full of warm happy thoughts. This part was fascinating: The removal took about half the width of my eyelid rim above the area of removed tissue. They took skin from my left eyelid and grafted it on. To do that, they cut right along the crease of my left eyelid, removed some skin, and sutured the eyelid back together. Then they sewed those two strips of skin (I think it was two, I was a little drowsy) below my right eye, creating a new portion of eyelid rim and filling the hole. Amazing that we can do this stuff. The surgery itself took about an hour. Recovery was quick. I was home eating a giant Chipotle bowl very soon after. It was delicious. Pain: minimal. Took Tylenol that first night and following day, then didn’t need it again. Antiobiotic ointment applied 3x a day. This is annoying as fuck because I have to make sure I get a lot of ointment on that lid margin (very important to keep it moisturized) which means some ointment always gets in my eye so vision is blurred for an hour+ every time I apply. Swelling: yes. Bruising: some. Not as much as I anticipated. Itchy and irritated: YES. OMG. I get the dressing & sutures off tomorrow morning and I CANNOT WAIT. Here’s how it looks today (six days post-op): Oh, what’s that? You were hoping for an EYELID SURGERY RECOVERY MONTAGE of POOR QUALITY PHOTOS documenting the healing process from DAY 1 TO DAY 6 POST-OP? I’ve got that right here for you. Also I did not have health insurance at the time so even if I had been worried about it I probably wouldn’t have done anything. Say you're in the U.S. without saying you’re in the U.S. The eyelid margin is the “edge” of the eyelid. Also known as the mucocutaneous margin. Eyelashes grow from the margin & there are glands that produce oil to help keep the eye moisturized. Detailed explanation of  Mohs Micrographic Surgery . Molecular imaging of different skin cancer cells vs normal skin cells. Local anesthetic (needle in the cheek below the right eyelid). They lean you back in a chair and tuck surgical drapes around the area. Assisting docs hold the head still and hold the eyelid open or closed or whatever it needs to be. It’s pretty surreal to see a scalpel coming directly toward your eyeball. But the most surreal part was hearing the snip-snip-snip of scissors knowing it’s my skin  that’s being snipped off my face . Pain: none. They gave me another shot of anesthetic right before they patched me up which was nice. Hungry (no eating allowed before the reconstruction surgery). Did some Christmas shopping. Pirate impressions. Thought about food. Went to the bathroom a couple of times to peek under the bandage and make sure my eye was still there. Then the anesthetic wore off so I didn’t need to do that anymore. Contemplated the hierarchy of snacks. Assured 4 different nurses that there is zero possibility of pregnancy, no really, I promise, I do not have a uterus . Speaking of the beast (not) in me: Watched a couple of episodes of The Beast In Me . Looked at the entire Internet. Thought about food some more. Napped a little. Sedation (via IV) plus local anesthetic. I was very relaxed and full of warm happy thoughts. This part was fascinating: The removal took about half the width of my eyelid rim above the area of removed tissue. They took skin from my left eyelid and grafted it on. To do that, they cut right along the crease of my left eyelid, removed some skin, and sutured the eyelid back together. Then they sewed those two strips of skin (I think it was two, I was a little drowsy) below my right eye, creating a new portion of eyelid rim and filling the hole. Amazing that we can do this stuff. The surgery itself took about an hour. Recovery was quick. I was home eating a giant Chipotle bowl very soon after. It was delicious. Pain: minimal. Took Tylenol that first night and following day, then didn’t need it again. Antiobiotic ointment applied 3x a day. This is annoying as fuck because I have to make sure I get a lot of ointment on that lid margin (very important to keep it moisturized) which means some ointment always gets in my eye so vision is blurred for an hour+ every time I apply. Swelling: yes. Bruising: some. Not as much as I anticipated. Itchy and irritated: YES. OMG. I get the dressing & sutures off tomorrow morning and I CANNOT WAIT. Also I did not have health insurance at the time so even if I had been worried about it I probably wouldn’t have done anything. Say you're in the U.S. without saying you’re in the U.S. The eyelid margin is the “edge” of the eyelid. Also known as the mucocutaneous margin. Eyelashes grow from the margin & there are glands that produce oil to help keep the eye moisturized. Detailed explanation of  Mohs Micrographic Surgery . Molecular imaging of different skin cancer cells vs normal skin cells.

Personal Experience Surgery Health
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Kix Panganiban 1 months ago

Great device, wrong problem: Two months with the Ultrahuman Air

I've been wearing an Apple Watch daily for the last 7-ish years now. It's kinda become part of my personality -- like, something feels off when I'm not wearing it. But lately, I thought I wanted a change. Maybe it’d be nice to wear a proper watch every now and then, or even go bare-wristed for a bit. So, a couple of months ago, I started hunting for an alternative device that could keep track of my health and stats -- which I figured was the main reason I wore my watch. After tons of research, I settled on the Ultrahuman Air. Some reviews mentioned that the Oura Ring seems generally more accurate, but the Ultrahuman does not require a subscription to fully utilize -- a total dealbreaker for me with the Oura Ring. I was stoked to try something new. It’s a fantastic device, no question. I was impressed. But as the weeks went on, I started to notice what it couldn’t do -- and that’s when I realized it's not replacing my watch. So I’ve come to realize that health tracking isn’t even the main thing I use my Apple Watch for -- it’s the alarms and notifications that keep my life together. This all means that while the Ultrahuman Air can definitely handle the health-tracking side of things, it can’t touch everything else I rely on the Apple Watch for. And now that both devices do a solid job at tracking stats, wearing two smart gadgets -- both needing charging and occasionally shining bright green lights at night -- feels redundant. I really love the Ultrahuman Air. It’s sleek, it’s smart, and it taught me a lot about my body. But it’s not the change I needed. So, it’ll probably be up on Facebook Marketplace soon. Maybe I’ll stick with my Apple Watch for now -- or who knows, maybe I’ll finally try going watch-free for a bit. We’ll see. Its app is fantastic. I love the design language they chose and how the stats are presented. Honestly, I didn’t know much about Heart Rate Variability (HRV) or VO2max until I wore the Ultrahuman Air, and now those are two stats I keep a close eye on. Handy features like Stress Rhythm and Caffeine Window feel a bit gimmicky, but they’ve got a ton of utility when you actually use them. The ring itself is super lightweight -- even lighter than a couple of carbide rings I like to wear. I barely notice it’s on, and its texturing makes it really scratch- and grime-resistant. Its reported stats are pretty close to what my Apple Watch shows, so without proper scientific gear to test it, I’m inclined to think they’re accurate enough. Its battery life is killer. I get about 4 and a half days on average -- compared to my Apple Watch, which I routinely charge before bed at night (thanks, low-battery anxiety issues). I wear my watch to bed so I can wake up at 5 AM without risking disturbing my wife and kid (who co-sleep with us). A phone alarm is a no-go since they’re both fairly light sleepers. I rely on reminders and message notifications to function. Seriously. With the amount of stuff I forget unless I write it down and set a reminder, the entire system I’ve built to manage my ADHD just breaks down without them. I use random Apple Watch features more than I realized: the handy flashlight that helps me navigate to the bathroom at midnight, the camera app that lets me take better group pics, and even the walkie-talkie that lets my wife and me ping each other quickly and directly.

Electronics Health
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ava's blog 2 months ago

one year of hair growth

At the end of October 2024, I cut all my hair off, and let my wife shave it off to 9mm. I wrote about that here . I did it because various illness and medication effects made me a lose a lot of hair. In November that year, I shaved it once more, down to 5mm, then let it grow. This is the current status: Have done nothing to it except letting it grow. It looks and feels healthy and seems like the hairloss has stopped and reversed. :) I still wear wigs most of the time I'm out of the home, though. Reply via email Published 12 Nov, 2025

writing Writing Health ai AI
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DYNOMIGHT 6 months ago

Do blue-blocking glasses improve sleep?

Back in 2017, everyone went crazy about these things: The theory was that perhaps the pineal gland isn’t the principal seat of the soul after all. Maybe what it does is spit out melatonin to make you sleepy. But it only does that when it’s dark, and you spend your nights in artificial lighting and/or staring at your favorite glowing rectangles. You could sit in darkness for three hours before bed, but that would be boring. But—supposedly—the pineal gland is only shut down by blue light. So if you selectively block the blue light, maybe you can sleep well and also participate in modernity. Then, by around 2019, blue-blocking glasses seemed to disappear. And during that brief moment in the sun, I never got a clear picture of if they actually work. So, do they? To find out, I read all the papers. Before getting to the papers, please humor me while I give three excessively-detailed reminders about how light works. First, it comes in different wavelengths . Outside the visible spectrum, infrared light and microwaves and radio waves have even longer wavelengths, while ultraviolet light and x-rays and gamma rays have even shorter wavelengths. Shorter wavelengths have more energy. Do not play around with gamma rays. Other colors are hallucinations made up by your brain. When you get a mixture of all wavelengths, you see “white”. When you get a lot of yellow-red wavelengths, some green, and a little violet-blue, you see “brown”. Similar things are true for pink/purple/beige/olive/etc. (Technically, the original spectral colors and everything else you experience are also hallucinations made up by your brain, but never mind.) Second, the ruleset of our universe says that all matter gives off light, with a mixture of wavelengths that depends on the temperature. Hotter stuff has atoms that are jostling around faster, so it gives off more total light, and shifts towards shorter (higher-energy) wavelengths. Colder stuff gives off less total light and shifts towards longer wavelengths. The “color temperature” of a lightbulb is the temperature some chunk of rock would have to be to produce the same visible spectrum. Here’s a figure , with the x-axis in kelvins. The sun is around 5800 K. That’s both the physical temperature on the surface and the color temperature of its light. Annoyingly, the orange light that comes from cooler matter is often called “warm”, while the blueish light that comes from hotter matter is called “cool”. Don’t blame me. Anyway, different light sources produce widely different spectra . You can’t sense most of those differences because you only have three types of cone cells . Rated color temperatures just reflect how much those cells are stimulated. Your eyes probably see the frequencies they do because that’s where the sun’s spectrum is concentrated. In dim light, cones are inactive, so you rely on rod cells instead. You’ve only got one kind of rod, which is why you can’t see color in dim light. (Though you might not have noticed.) Finally, amounts of light are typically measured in lux . Your eyes are amazing and can deal with upwards of 10 orders of magnitude . In summary, you get widely varying amounts of different wavelengths of light in different situations, and the sun is very powerful. It’s reasonable to imagine your body might regulate its sleep schedule based that input. OK, but do blue-blocking glasses actually work? Let’s read some papers. Kayumov et al. (2005) had 19 young healthy adults stay awake overnight for three nights, first with dim light (<5 lux) and then with bright light (800 lux), both with and without blue-blocking goggles. They measured melatonin in saliva each hour. The goggles seemed to help a lot. With bright light, subjects only had around 25% as much melatonin as with dim light. Blue-blocking goggles restored that to around 85%. I rate this as good evidence for a strong increase in melatonin. Sometimes good science is pretty simple. Burkhart and Phelps (2009) first had 20 adults rate their sleep quality at home for a week as a baseline. Then, they were randomly given either blue-blocking glasses or yellow-tinted “placebo” glasses and told to wear them for 3 hours before sleep for two weeks. Oddly, the group with blue-blocking glasses had much lower sleep quality during the baseline week, but this improved a lot over time. I rate this as decent evidence for a strong improvement in sleep quality. I’d also like to thank the authors for writing this paper in something resembling normal human English. Van der Lely et al. (2014) had 13 teenage boys wear either blue-blocking glasses or clear glasses from 6pm to bedtime for one week, followed by the other glasses for a second week. Then they went to a lab, spent 2 hours in dim light, 30 minutes in darkness, and then 3 hours in front of an LED computer, all while wearing the glasses from the second week. Then they were asked to sleep, and their sleep quality was measured in various ways. The boys had more melatonin and reported feeling sleepier with the blue-blocking glasses. I rate this as decent evidence for a moderate increase in melatonin, and weak evidence for near-zero effect on sleep quality. Gabel et al. (2017) took 38 adults and first put them through 40 hours of sleep deprivation under white light, then allowed them to sleep for 8 hours. Then they were subjected to 40 more hours of sleep deprivation under either white light (250 lux at 2800K), blue light (250 lux at 9000K), or very dim light (8 lux, color temperature unknown). Their results are weird. In younger people, dim light led to more melatonin that white light, which led to more melatonin that blue light. That carried over to a tiny difference in sleepiness. But in older people, both those effects disappeared, and blue light even seemed to cause more sleepiness than white light. The cortisol and wrist activity measurements basically make no sense at all. I rate this as decent evidence for a moderate effect on melatonin, and very weak evidence for a near-zero effect on sleep quality. (I think its decent evidence for a near-zero effect on sleepiness, but they didn’t actually measure sleep quality.) Esaki et al. (2017) gathered 20 depressed patients with insomnia. They first recorded their sleep quality for a week as a baseline, then were given either blue-blocking glasses or placebo glasses and told to wear them for another week starting at 8pm. The changes in the blue-blocking group were a bit better for some measures, but a bit worse for others. Nothing was close to significant. Apparently 40% of patients complained that the glasses were painful, so I wonder if they all wore them as instructed. I rate this was weak evidence for near-zero effect on sleep quality. Shechter et al. (2018) gave 14 adults with insomnia either blue-blocking or clear glasses and had them wear them for 2 hours before bedtime for one week. Then they waited four weeks and had them wear the other glasses for a second week. They measured sleep quality through diaries and wrist monitors. The blue-blocking glasses seemed to help with everything. People fell asleep 5 to 12 minutes faster, and slept 30 to 50 minutes longer, depending on how you measure. (SOL is sleep onset latency, TST is total sleep time). I rate this as good evidence for a strong improvement in sleep quality. Knufinke et al. (2019) had 15 young adult athletes either wear blue-blocking glasses or transparent glasses for four nights. The blue-blocking group did a little better on most measures (longer sleep time, higher sleep quality) but nothing was statistically significant. I rate this as weak evidence for a small improvement in sleep quality. Janků et al. (2019) took 30 patients with insomnia and had them all go to therapy. They randomly gave them either blue-blocking glasses or placebo glasses and asked the patients to wear them for 90 minutes before bed. The results are pretty tangled. According to sleep diaries, total sleep time went up by 37 minutes in the blue-blocking group, but slightly decreased in the placebo group. The wrist monitors show total sleep time decreasing in both groups, but it did decrease less with the blue-blocking glasses. There’s no obvious improvement in sleep onset latency or the various questionnaires they used to measure insomnia. I rate this as weak evidence for a moderate improvement in sleep quality. Esaki et al. (2020) followed up on their 2017 experiment from above. This time, they gathered 43 depressed patients with insomnia. Again, they first recorded their sleep quality for a week as a baseline, then were given either blue-blocking glasses or placebo glasses and told to wear them for another week starting at 8pm. The results were that subjective sleep quality seemed to improve more in the blue-blocking group. Total sleep time went down by 12.6 minutes in the placebo group, but increased by 1.1 minutes in the blue-blocking group. None of this was statistically significant, and all the other measurements are confusing. Here are the main results. I’ve added little arrows to show the “good” direction, if there is one. These confidence intervals don’t make any sense to me. Are they blue-blocking minus placebo or the reverse? When the blue-blocking number is higher than placebo, sometimes the confidence interval is centered above zero (VAS), and sometimes it’s centered below zero (TST). What the hell? Anyway, they also had a doctor estimate the clinical global impression for each patient, and this looked a bit better for the blue-blocking group. The doctor seemingly was blinded to the type of glasses the patients were wearing. This is a tough one to rate. I guess I’ll call it weak evidence for a small improvement in sleep quality. Guarana et al. (2020) sent either blue-blocking glasses or sham glasses to 240 people, and asked them to wear them for at least two hours before bed. They then had them fill out some surveys about how much and how well they slept. Wearing the blue-blocking glasses was positively correlated with both sleep quality and quantity with a correlation coefficient of around 0.20. This paper makes me nervous. They never show the raw data, there seem to be huge dropout rates, and lots of details are murky. I can’t tell if the correlations they talk about weight all people equally, all surveys equally, or something else. That would make a huge difference if people dropped out more when they weren’t seeing improvements. I rate this as weak evidence for a moderate effect on sleep. There’s a large sample, but I discount the results because of the above issues and/or my general paranoid nature. Domagalik et al. (2020) had 48 young people wear either blue-blocking contact lenses or regular contact lenses for 4 weeks. They found no effect on sleepiness. I rate this as very weak evidence for near-zero effect on sleep. The experiment seems well-done, but it’s testing the effects of blocking blue light all the time, not just at night. Given the effects on attention and working memory, don’t do that. Bigalke et al. (2021) had 20 healthy adults wear either blue-blocking glasses or clear glasses for a week from 6pm until bedtime, then switch to the other glasses for a second week. They measured sleep quality both through diaries (“Subjective”) and wrist monitors (“Objective”). The differences were all small and basically don’t make any sense. I rate this weak evidence for near-zero effect on sleep quality. Also, see how in the bottom pair of bar-charts, the y-axis on the left goes from 0 to 5, while on the right it goes from 30 to 50? Don’t do that, either. I also found a couple papers that are related, but don’t directly test what we’re interested in: Appleman et al. (2013) either exposed people to different amounts of blue light at different times of day. Their results suggest that early-morning exposure to blue light might shift your circadian rhythm earlier. Sasseville et al. (2015) had people stay awake from 11pm to 4am on two consecutive nights, while either wearing blue-blocking glasses or not. With the blue-blocking glasses there was more overall light to equalizing the total incoming energy. I can’t access this paper, but apparently they found no difference. For a synthesis, I scored each of the measured effects according to this rubric: And I scored the quality of evidence according to this one: Here are the results for the three papers that measured melatonin: And here are the results for the papers that measured sleep quality: We should adjust all that a bit because of publication bias and so on. But still, here are my final conclusions after staring at those tables: There is good evidence that blue-blocking glasses cause a moderate increase in melatonin. It could be large, or it could be small, but I’d say there’s an ~85% chance it’s not zero. There is decent evidence that blue-blocking glasses cause a small improvement in sleep quality. This could be moderate (or even large) or it could be zero. It might be inconsistent and hard to measure. But I’d say there’s an ~75% chance there is some positive effect. I’ll be honest—I’m surprised. If those effects are real, do they warrant wearing stupid-looking glasses at night for the rest of your life? I guess that’s personal. But surely the sane thing is not to block blue light with headgear, but to not create blue light in the first place. You can tell your glowing rectangles to block blue light at night, but lights are harder. Modern LED lightbulbs typically range in color temperature from 2700K for “warm” lighting to 5000 K for “daylight” bulbs. Judging from this animation that should reduce blue frequencies to around 1/3 as much. Old-school incandescent bulbs are 2400 K. But to really kill blue, you probably want 2000K or even less. There are obscure LED bulbs out there as low as 1800K. They look extremely orange, but candles are apparently 1850K, so probably you’d get used to it? So what do we do then? Get two sets of lamps with different bulbs? Get fancy bulbs that change color temperature automatically? Whatever it is, I don’t feel very optimistic that we’re going to see a lot of RCTs where researchers have subjects install an entire new lighting setup in their homes. Appleman et al. (2013) either exposed people to different amounts of blue light at different times of day. Their results suggest that early-morning exposure to blue light might shift your circadian rhythm earlier. Sasseville et al. (2015) had people stay awake from 11pm to 4am on two consecutive nights, while either wearing blue-blocking glasses or not. With the blue-blocking glasses there was more overall light to equalizing the total incoming energy. I can’t access this paper, but apparently they found no difference. There is good evidence that blue-blocking glasses cause a moderate increase in melatonin. It could be large, or it could be small, but I’d say there’s an ~85% chance it’s not zero. There is decent evidence that blue-blocking glasses cause a small improvement in sleep quality. This could be moderate (or even large) or it could be zero. It might be inconsistent and hard to measure. But I’d say there’s an ~75% chance there is some positive effect.

Science data-analysis Data Analysis Health
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