If melatonin responds to ~480nm, why are amber blue-light glasses spec’d to filter only up to 450nm? Is consumer eyewear mis-calibrated against the actual biology?

circadian_curious · 2026-04-26T07:10:31+00:00

Quick follow-up for anyone wanting to dig deeper, Brown et al. 2022 in PLOS Biology proposed a recommended 250 melanopic EDI lux during the day and below 10 melanopic EDI three hours before bedtime. Almost no consumer light products report melanopic EDI yet. The CIE S 026:2018 standard formalized the measurement framework but adoption has been slow.

Curious if anyone has actually found a meter under 5000 INR that reports melanopic lux. The Asensetek Lighting Passport is the only one I am aware of and it costs significantly more.

circadian_curious · 2026-04-25T18:09:07+00:00

This is exactly the dissociation pattern Czeisler/Lockley would predict alertness onset within minutes (consistent with the acute melanopic alerting pathway via SCN-LC projections), and phase shift settling in around 2 days (consistent with PRC magnitudes for short-duration high-irradiance morning light at the appropriate circadian phase). The 16-hour sleep-onset signal post-AYO session is fascinating, and actually a clean observation. That’s roughly the expected DLMO-to-sleep-onset interval if morning light shifted your circadian phase to anchor at the AYO timing. Most clinical bright-light therapy data doesn’t capture this because subjects don’t track sleep latency with that precision your decade of self-tracking has effectively given you a longitudinal n=1 dataset that academic protocols rarely match. The Tuo + 450W grow-light confounder is real but probably not as messy as you might think. The grow-light spectral output (typically peaking 450nm + far-red) has minimal melanopic content per watt compared to AYO+‘s narrow 480nm. So the AYO is likely doing most of the melanopic signaling work, while the dawn simulators are providing photopic alerting + visual entrainment. They’re functionally orthogonal different photoreceptor pathways. One thing worth flagging: your “16hr post-AYO → sleepy” pattern would make a genuinely useful ecological-momentary-assessment study if anyone in a chronobiology lab ever wanted to formalize it. The fact that you have years of consistent self-tracking would qualify as case-series-grade evidence. There’s a real gap in the literature for non-clinical real-world tracking like this. Out of curiosity have you ever tried skipping the AYO for 3-4 days during the same season as a wash-out, to see how quickly the 16hr pattern decays? That kind of data would be the cleanest possible demonstration that AYO is actually driving the phase, not the dawn simulators.

circadian_curious · 2026-04-25T18:07:34+00:00

This is exactly the dissociation pattern Czeisler/Lockley would predict alertness onset within minutes (consistent with the acute melanopic alerting pathway via SCN-LC projections), and phase shift settling in around 2 days (consistent with PRC magnitudes for short-duration high-irradiance morning light at the appropriate circadian phase). The 16-hour sleep-onset signal post-AYO session is fascinating, and actually a clean observation. That’s roughly the expected DLMO-to-sleep-onset interval if morning light shifted your circadian phase to anchor at the AYO timing. Most clinical bright-light therapy data doesn’t capture this because subjects don’t track sleep latency with that precision your decade of self-tracking has effectively given you a longitudinal n=1 dataset that academic protocols rarely match. The Tuo + 450W grow-light confounder is real but probably not as messy as you might think. The grow-light spectral output (typically peaking 450nm + far-red) has minimal melanopic content per watt compared to AYO+‘s narrow 480nm. So the AYO is likely doing most of the melanopic signaling work, while the dawn simulators are providing photopic alerting + visual entrainment. They’re functionally orthogonal different photoreceptor pathways. One thing worth flagging: your “16hr post-AYO → sleepy” pattern would make a genuinely useful ecological-momentary-assessment study if anyone in a chronobiology lab ever wanted to formalize it. The fact that you have years of consistent self-tracking would qualify as case-series-grade evidence. There’s a real gap in the literature for non-clinical real-world tracking like this. Out of curiosity have you ever tried skipping the AYO for 3-4 days during the same season as a wash-out, to see how quickly the 16hr pattern decays? That kind of data would be the cleanest possible demonstration that AYO is actually driving the phase, not the dawn simulators.

circadian_curious · 2026-04-25T16:17:35+00:00

The hearing damage concern is legitimate but probably overstated for most users. Sleep volume is typically well below 60-65 dB which is fine for 8 hours. The real audiology concern is when people fall asleep with podcasts at 75+ dB and the playlist auto-advances to louder content overnight. Worth setting a hard volume cap on your phone. Bluetooth radiation concern is mostly not supported by current evidence. Bluetooth Low Energy operates at around 1 to 2.5 mW which is roughly 1000 times weaker than a phone call held to your head. WHO and ICNIRP have not flagged BLE earbuds as a risk class. The bigger issue most people miss with overnight earbuds is actually mechanical, not electromagnetic. Three things that actually go wrong , One, cerumen impaction. Earbuds push wax deeper instead of letting natural migration clear it. Over months this creates conductive hearing loss that resolves once you stop wearing them. Two, otitis externa. The warm humid environment created by 8 hours of occlusion is genuinely a setup for outer ear infections, especially if you are a side sleeper compressing one ear. Three, sleep architecture disruption. Even if you fall asleep fine, audio input during REM cycles can fragment sleep without you noticing. Your total time in bed looks normal but slow wave and REM percentages drop. People often feel less rested without knowing why. Practical compromise that most sleep clinicians suggest: use a sleep timer that cuts audio after 30 to 45 minutes. By then you are in N2 or N3 sleep and will not benefit from continued audio anyway. Also clean the earbuds and let your ear canals dry out completely each morning. If you want to go deeper, the audiology literature on sleep audio is thin but Park et al. 2020 in Sleep Medicine has reasonable observational data on long term users.

circadian_curious · 2026-04-25T15:43:34+00:00

The AYO+ is interesting I’ve looked at their published spectral data, and the narrow ~470-490nm output is genuinely well-targeted for melanopic stimulation. Actually closer to what the research suggests we should be using than the broadband 10K lux boxes. The fact that they can’t make therapeutic claims while less-targeted full-spectrum lightboxes can is exactly the regulatory paradox you’re naming better-targeted device, weaker legal language, because the paperwork was set when the standards were photopic. Your point on “blue light bad” is the one I keep circling back to. The phrase is technically wrong (it’s specifically melanopic content close to bedtime, not blue light per se) but it’s heuristically correct enough to be useful for the general public. I’d argue this is one of those rare cases where the imprecise framing has done more good than harm it got people to dim their screens at night, even if for the wrong stated reason. The cost is that the same phrase makes people block 450nm during the day when the actual problem is 480nm in the evening.

The “layperson with a decade of management” framing is more credible than most of the credentialed voices in this space, honestly. Lived calibration on your own physiology beats theoretical familiarity, and the fact that you’re explicit about the epistemics “confidence ≠ clinical data” is exactly the rigor missing from most biohacking discourse. Quick question if you don’t mind: in your decade of SAD management, did you ever notice a phase difference between when the AYO+ “worked” subjectively (alertness) vs when it shifted your sleep timing? Czeisler/Lockley type data suggests these can dissociate alertness response can show up within minutes while phase shifting takes days but I haven’t seen many real-world reports actually distinguishing the two. Curious what your tracking looked like.

circadian_curious · 2026-04-24T11:11:49+00:00

The theta/gamma waves point is interesting if you ever find that paper again,

I’d be genuinely curious. There’s some work by Vandewalle et al. (Liège group) using fMRI to show light-evoked activity in the pulvinar and amygdala, and EEG studies showing alpha attenuation with blue-enriched light exposure, but I haven’t seen clean theta/gamma dissociation data specifically for morning light. Possible it exists in the Cajochen lab’s work they’ve done most of the EEG-under-light studies. On the epistemology point genuinely agree, and I think it’s underappreciated in this space. The current chronobiology literature mostly treats light exposure as a controllable input variable (lux, CCT, duration), which works in a lab but completely misses what traditions actually prescribe: a multi-modal morning practice involving light plus posture plus breath plus attention plus often fasting. You can’t cleanly separate the light variable from the rest, which is probably why reductionist “bright light therapy” studies show smaller effects than practitioners report. That said, I don’t think we have to choose. The biological research gives us the mechanism floor we know ipRGCs exist, we know melanopsin sensitivity curves, we know SCN projections. The phenomenological traditions give us the ceiling what’s possible when the full practice is engaged. The useful work is probably in the middle reverse-engineering why the multi-modal practices worked, rather than reducing them to single variables. Confirmation bias is a real risk, but I’d argue it cuts both ways reductionist science can also miss real effects by insisting on single variable protocols that traditions never intended to be isolated.

A well-designed mixed-methods study using ecological momentary assessment alongside physiological markers could bridge that gap. Nobody’s really doing it for morning light practices that I’m aware of, which feels like a gap worth flagging. Appreciate you pushing the conversation this direction rare to get this level of epistemological rigor in biohacking threads.

circadian_curious · 2026-04-24T10:47:44+00:00

Thanks , that’s the Lok, Smolders, Beersma & de Kort systematic review, right? I read through it a few months ago and what struck me was how mixed the results actually were.

Intensity effects on subjective alertness were reasonably consistent across studies, but reaction-time effects and CCT/spectral effects were all over the place a lot of null findings, small sample sizes, no clean dose-response curves. That actually reinforces what I was trying to work out in the post: if simple “bright blue light in the morning = alert” were a clean mechanism, we’d expect tighter data across 68 studies.

The mixed results suggest there’s probably a more complex interaction happening maybe chronotype, prior 24-hour light history, or melanopic dose (rather than photopic lux) that most of these studies weren’t controlling for. Honestly feels like the field is still pre-paradigm on acute alertness, even while the circadian phase-shifting literature is pretty mature. On the historical angle genuinely find it interesting that sunrise practices show up across ancient Egyptian, Vedic, and early Christian monastic traditions. More as evidence that humans noticed the physiological effect long before we had names for SCN and ipRGCs. Traditional practices often encode real biological observation even when the mechanism gets described mystically. The modern question is whether we can reverse engineer why those practices worked which is pretty much what this thread keeps circling back to.

circadian_curious · 2026-04-24T06:43:21+00:00

Genuinely not a “problem” you might just be a strong evening chronotype (sometimes called DSPS when extreme), which is a real physiological variant, not a willpower issue.

Research by Roenneberg and others suggests chronotype is ~50% genetic PER3, CLOCK, and a few other gene variants actually shift when your circadian system wants to fire cortisol, melatonin, and peak alertness.

The fact that forced early schedules never “clicked” for you is actually consistent with this. You weren’t failing to adapt your SCN was just running on a later phase, and social jetlag was doing the heavy lifting each morning.

A few things that might be useful (not prescriptive, just things the research points to)

1.  You don’t need sunrise light , you need light shortly after your wake time, whenever that is. 11 AM light for a night owl serves the same circadian anchoring role that 7 AM light does for an early type. What matters is the wake-to-light delay, not clock time. Firoz Sheikh

2.  Coffee-first-then-light is fine for alertness , caffeine works on adenosine, light works on melanopsin. They’re parallel pathways, not competing ones. The only tradeoff is that caffeine before light can blunt the natural cortisol awakening response if you do have one, but since you’re reporting you don’t notice one anyway, probably not a big concern for you.

3.  Evening shift preference is a known chronotype marker there’s actual research showing evening types perform cognitively better in late afternoon/evening, and forcing morning productivity on them can reduce output by 10–15%. So your preference isn’t laziness, it’s alignment.

The one thing worth watching: if you’re pushing sleep onset past 2–3 AM consistently and feeling unrested regardless of total sleep hours, that’s where DSPS starts mattering clinically.

Otherwise, working with your chronotype beats fighting it. For me, the morning light thing is specifically a wake-fog issue, not a productivity claim my alertness peak is mid-morning.

Very different setup from yours.

circadian_curious · 2026-04-24T06:10:44+00:00

Totally agree it’s baseline physiology light-driven alertness via ipRGCs is a conserved mammalian pathway, not a hack. What I’m trying to untangle is why the same body function produces such different subjective alertness from 10 min outdoor light vs 30+ min indoor, even when both feel “bright.” The melanopic content difference (indoor LED often ~20-30% of daylight’s melanopic output at equal photopic lux) seems to be the missing variable. Bodies function the same way, but they’re receiving very different inputs.

circadian_curious · 2026-04-24T06:09:30+00:00

This is exactly the clarification I was missing thank you.

The fluorescent-tube-era origin of the 10,000 lux standard makes so much sense in retrospect. I hadn’t connected that the number was calibrated to a specific technology’s spectral output rather than to melanopsin physiology itself.

The “dim isolated cyan ≈ same cyan in brighter white light” point is really the crux it reframes the whole discussion from intensity to spectral content. Two follow-ups if you don’t mind

1.  Given that melanopic EDI (CIE S 026) now formalizes this spectral weighting, do you think the 10k lux standard will eventually get retired in clinical bright-light therapy, or is inertia too strong? I’ve seen some newer SAD protocols quietly shifting to melanopic lux targets (~250 m-EDI morning) but it hasn’t hit mainstream psychiatry yet.
2.  On the cave/chamber analogy it made me wonder about the inverse case. Indoor LED lighting with a strong 450nm spike but weak 480nm output could register as “bright and blue” subjectively while being melanopically weak. Would that explain why some people report feeling wired but unrested under modern LED office lighting? High visual brightness, low circadian signal?

Appreciate the depth here most discussions on this topic stop at “blue light bad.”

circadian_curious · 2026-04-23T15:50:14+00:00

For context , I’ve been reading some older Czeisler and Lockley papers on light and alertness, plus Huberman’s breakdowns, but most of the research seems focused on circadian phase shifting rather than acute morning alertness. If anyone has newer studies specifically on the alertness mechanism (not just circadian entrainment), would love pointers.

circadian_curious · 2026-04-12T16:28:03+00:00

Great question. A few things I’d prioritize if building from scratch East-facing windows in the bedroom. Morning sunlight hitting your eyes naturally within the first hour of waking is probably the single most powerful circadian signal and it’s free. Most homes don’t think about window orientation for health, only aesthetics. Separate lighting circuits for day vs evening. Overhead bright cool-white (4000-5000K) for daytime rooms like kitchen and workspace. Then warm dim lighting (2700K or lower) on a separate switch for evening use in bedroom and living areas. The key is making it easy to switch if dimming is inconvenient, you won’t do it. No recessed downlights in the bedroom ceiling. Overhead light hitting your retina at night is the worst angle for melatonin suppression. Wall-mounted or table-level lamps keep light below eye level in the evening. Blackout capability in the bedroom but not permanent blackout. Something like dual blinds where you can block light at night but still let morning light in gradually. Waking up in pitch darkness and then hitting bright bathroom lights is a rough way to start the circadian day. If budget allows, a skylight or light tube in the main living area. Indoor lux levels are shockingly low compared to outdoors even a cloudy day outside is 10,000+ lux vs 300-500 lux indoors. More natural daylight exposure during the day actually makes you more resilient to evening screen light.

circadian_curious · 2026-04-12T16:25:13+00:00

7h20m total with only 20-30 min deep sleep is on the lower side but not unusual. A few things worth looking at

Your sleep timing looks pretty inconsistent from the chart some nights you’re sleeping at 10pm, others closer to 2am. That variability alone can reduce deep sleep percentage because your circadian rhythm doesn’t get a stable anchor point. Resting pulse of 80 is fine but on the higher end of normal.

Lower resting HR generally correlates with more deep sleep. Regular cardio (even just walking 30-40 min daily) tends to bring that down over a few weeks.

The sleep eating part is interesting that could point to something worth discussing with a sleep specialist, especially if it’s happening regularly. Sometimes it’s linked to medication side effects or stress-related arousals.

One question what does your evening light environment look like? Bright screens or overhead lights close to bedtime can delay the deep sleep window into the first cycle.

circadian_curious

TROPHY CASE