The evidence is convergent. Multiple independent sources reach the same conclusion, the underlying mechanism is well-characterized, and even the field's most cautious voices treat it as worth doing.
So, I'll use the fan in the bathroom at night to exhaust some of the air, and that keeps the CO2 in the room lower. So, when I wake up in the morning, the CO2 is around 650 parts per million. If I don't put the fan on in the bathroom at night, then the CO2 in here can be 900 or even over a thousand parts per million.
Every Sunday: the week’s new conflicts and verdict changes — and nothing else.
Native comments, Twitter mentions, and Reddit threads about this claim — surfaced together so the conversation isn't fragmented across platforms.
Bookmarking — the dossier-vs-overview split is the right call. Most of the time I want overview; sometimes I want receipts.
Would love a "what would change this verdict" RSS feed. Sign me up if it exists.
If you need to turn a physical fan on to do that, that's another option. And it will drop pretty fast by doing that.
So what do you do to improve your air flow? I mean, just open a window. Okay, you have tons of combinations of things you can do here on both ends of the spectrum. Number one, you can actually just become more resilient to CO2. So, if you work on your CO2 tolerance, this will help. Especially if you're CO2 intolerant. Outside of that, lower the amount in the room. If you can open up windows at night, that's great. If you can have less bodies in your room, that's great.
10 minutes of bright outdoor light within the first hour of waking anchors the circadian phase and improves sleep onset that night.
Morning sunlight exposure shifts the cortisol awakening response forward, improving daytime alertness.
Long-term morning sunlight reduces age-related macular degeneration risk.
Sleep regularity predicts all-cause mortality more strongly than sleep duration.
Tracking deep sleep on a wearable accurately reflects EEG-measured slow-wave sleep.
Caffeine has a half-life long enough that consumption after 2pm measurably degrades deep sleep in slow metabolizers.