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Sleep Groove is a myth-busting guide to circadian science that teaches you to work with your body’s natural rhythms rather than fight them, using accessible explanations, charts, and comics.
As I get older, I wake up in the middle of the night more than I did in my twenties and thirties. A lot of people my age tell me the same thing. Sleep Groove gave me a new way to think about it. Walch argues that the strength and steadiness of your daily rhythm are more important than a single long, unbroken stretch of sleep.
When your internal clock has a strong, well-defined beat, your sleep consolidates around it. When that rhythm flattens out, which tends to happen as we age, sleep breaks into pieces, and you wake more often during the night.
The fix is to make your clock beat louder by keeping a fixed wake-up time, getting bright light early in the day, and staying in darkness at night. Since I started protecting my rhythm, my night wakings have gotten shorter, and I drop back to sleep faster.
Core Principles
1. Regularity Beats Duration
Forget the eight-hour rule. Research shows that sleep regularity (how much your sleep schedule on one day resembles your sleep schedule the next day) predicts health outcomes better than total hours of sleep. Going to bed and waking up at the same time every day matters more than hitting a magic number.
2. Light Is a Drug
Light exposure is the most powerful tool for setting your circadian clock, but timing is everything. Bright light during midday boosts your system and strengthens your rhythms. Light during your biological night confuses your brain and throws everything off. The same light can help or harm, depending on when you get it.
3. Find the Beat, Then Groove With It
Your body is wired to cycle through a biological rhythm, and when your sleep doesn’t follow that pattern, you feel terrible. The same goes for food, activity, and mood. All of it is rhythmic, and acknowledging that is the first step to feeling better.
4. You Can’t Bank Sleep
Oversleeping on weekends doesn’t make up for undersleeping during the week. Sleep debt doesn’t work like a bank account. The goal isn’t to average out over time but to establish consistent rhythms your body can rely on day after day.
Try It Now
Pick a wake-up time and stick to it every day this week, including weekends. Regularity matters more than duration.
Get outside for 15-30 minutes around midday. Bright natural light strengthens your circadian amplitude.
If you wake up in the middle of the night, stay in the dark. Don’t check your phone. Let your body find its way back to sleep.
06/12/26
