Airplane during golden hour. — a Sleep Finally guide to What Causes Social Jet Lag.

Dec 27, 2025 · 8 min read

What Causes Social Jet Lag

What causes social jet lag: the gap between alarm-clock weekdays and your body's weekend drift. The arithmetic, why it runs later, and the anchor that fixes it.

Circadian Rhythm Explained Simply

Dec 22, 2025 · 7 min read

Circadian Rhythm Explained Simply

Circadian rhythm explained simply: the 20,000-cell clock that runs on light, why it drifts, and the morning habit that resets it without gadgets.

Sleep-themed photo for how much sleep debt is too much

Dec 21, 2025 · 7 min read

How Much Sleep Debt Is Too Much

How much sleep debt is too much: a week of short nights leaves a real deficit no weekend repays in two sittings, and the anchor that stops the slide is wake time.

Sleep-themed photo for how to find your personal coffee cutoff time

Dec 20, 2025 · 7 min read

How to Find Your Personal Coffee Cutoff Time

Your personal coffee cutoff is a bedtime math problem: count back eight hours from lights out, run a two-week experiment, and let your own log find the line.