The department of
Caffeine
Caffeine affects sleep timing, depth, and quality in ways worth understanding. Explore half-life, sensitivity, timing, and how much is too much with science and honest reviews.
Pieces
6
Sleep
August 2026 · 9 min
What Four Fitness Trackers Told Me About My 2 p.m. Coffee: 100 Nights, One Number, and 17 Minutes
Seventeen minutes. That is the number this piece is built on: the median difference in how long it took me to fall asleep on nights when I'd had caffeine after 2 p.m.
By James Hartley · Read →
Sleep
August 2026 · 6 min
What Fitness Tracker Wearables Can Actually See When You Drink Coffee at Four in the Afternoon
I drank a double espresso at 4:15 on a Tuesday afternoon — about 130 mg of caffeine, roughly a small diner coffee — and then went to bed at 11:20 with a band on my wrist. I knew it was a bad idea.
By Daniel Whitfield · Read →
Sleep
August 2026 · 6 min
Smartwatch Deals and the 2pm Rule: Five Watches, One Evening Coffee, Six Weeks of Data
Every September the wearables go on the front page, and a certain kind of buyer — me, for about six years — starts justifying the upgrade with sleep. The pitch writes itself.
By Samuel Briggs · Read →
Sleep
August 2026 · 10 min
Down Jacket Reviews From the 6 a.m. Coffee Walk: Five Jackets, 41 Dark Mornings, One Sleep Log
Last winter I bought five down jackets in nine days and wore each of them on the same pre-dawn loop, with the same dog, after the same 200 mg of coffee.
By Elliot Carver · Read →
Sleep
August 2026 · 5 min
Apple Watch Deals Before the Series 12: I Wore Three Generations to Bed for 41 Nights
The sleep-tracking upgrade you're waiting for already shipped, and it shipped in 2022. Everything after that has been faster charging, a brighter screen at 3 a.m., and a slightly nicer thing to have…
By Marcus Webb · Read →
Sleep
August 2026 · 6 min
European Train Travel vs. the 06:25 Flight: I Tracked My Sleep and My Coffee Across 2,340 Kilometres
A night train is sold on a single number: seven hours of travel that cost you nothing, because you were going to be unconscious anyway.
By Emily Drayton · Read →
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