In winter I get up at night
And dress by yellow candlelight.
In summer, quite the other way,
I have to go to bed by day.
I cannot wait for the return of Standard Time!
The above lines by Robert Louis Stevenson return to me every morning these days. In point of fact, I have been "dressing by yellow candlelight" all summer, too. In Orlando, the earliest sunrise is about 6:30 EDT, which occurs in early June, and the latest sunset about 8:30 EDT, in late June. According to reality (sun time as opposed to clock time), these numbers are 5:30 for the earliest sunrise, and 7:30 for the latest sunset, which my own body clock finds much more reasonable.
Recently I came upon the advice that the first thing we should do when we awaken in the morning—specifically, within the first 10 minutes—is to expose our eyes to sunlight.
I'm a big fan of sunshine—I live in the Sunshine State after all—but my immediate reaction was the impossibility of following that advice for anyone who, like me, is up well before the sun peeks over the horizon. And what about Alaskans and Scandinavians?
I decided to ask Claude for the extremes of sunrise and sunset for Central Florida, and that led into the following conversation:
My prompt: These thoughts were inspired by reading someone's theory that it's important for our metabolic health that our eyes take in actual sunlight during the first 10 minutes or so after waking up. My reaction was that that sounds good, but it's not going to happen with any consistency, not only because of modern artificial light, but because the times of sunlight vary so much geographically. Have you ever heard of that theory? If so, what do you know about it?
Claude's response:
Yes — that's a real and pretty widely discussed idea, most associated these days with Andrew Huberman (Stanford neuroscientist with a popular podcast), though the underlying science predates him by decades in circadian biology research.
The core mechanism, briefly: Your eyes have specialized retinal cells (ipRGCs — intrinsically photosensitive retinal ganglion cells) that don't contribute to vision but feed directly into your suprachiasmatic nucleus, the brain's master circadian clock. Bright light exposure early in the day — especially the low-angle light around sunrise, which is rich in certain wavelengths — helps set that clock, which cascades into timing for cortisol release, melatonin onset later that night, and various metabolic processes (insulin sensitivity, body temperature rhythm, etc.).
What's solid: The general principle that morning light exposure helps anchor circadian rhythms is well-established in sleep and chronobiology research, going back to work in the 1980s-90s. Poor circadian alignment is genuinely linked to worse metabolic outcomes — shift workers, for instance, show elevated rates of metabolic syndrome. Light intensity matters a lot: outdoor light even on an overcast day is far brighter than typical indoor lighting (think 1,000-10,000+ lux outside vs. 100-300 lux in a typical room).
Where it gets oversold: The specific claims — that it has to be within the first 10 minutes, that it has to be actual sunrise, that you need a precise duration — go well beyond what the research actually nails down. Most of the underlying studies show benefits from "bright light exposure earlier in the day" generally, not a narrow 10-minute window. That kind of precision makes for a compelling podcast soundbite but isn't something the science actually demands.
Your instinct is right, too: the practical version of this advice — "get outside in the morning when you can" — is useful and low-cost. The rigid, must-be-within-minutes-of-waking version runs into exactly the problems you flagged: it's not achievable consistently for people with early alarms in winter, night-shift workers, or anyone at high latitudes where sunrise might be 9 AM in December. A "rule" that only works for early risers near the equator in summer isn't a robust health principle — it's a lifestyle-compatible one, dressed up as more universal than it is.
My next prompt: Thanks—although I would push back on the idea that it "works for early risers," since I am routinely up before the sun in Orlando (no alarm clock, just the way my body works), and natural light isn't available until much later. It's good to know that it's still helpful to get out in the sun once it shows up to the party.
Claude's response:
Fair pushback, and you're right — I stated that carelessly. "Early riser" doesn't line up with "sunlight available at wake time" at all; those are two different things that just happen to overlap for people whose wake time is late enough (or whose local sunrise is early enough) to coincide. You're up before the sun regardless of the clock, so the "within 10 minutes of waking" version of the rule was never going to apply to you no matter how you set your schedule.
The more accurate framing is probably: get bright light exposure reasonably early in your day, whenever the sun actually shows up relative to your own wake time — not tied to the moment you open your eyes. The circadian benefit comes from getting that light signal before too much of the day has passed, not from some magic window immediately post-wake. So for you, sun exposure shortly after sunrise (even if that's an hour or two after you're already up) should still be doing useful work — you're just not getting it in the first few minutes, and that's fine.
That is not only comforting but makes real sense. We humans could not have been designed (or evolved, if you prefer; for this point it makes no difference) to have our well-being depend on a very narrow window of time that has been unavailable for most of the population since long before the invention of electric lights.
It's also good to know that the anti-natural clock machinations of the government can't take away the benefits of early morning sunshine.
But I still can't wait for the return of Standard Time.
