# The Sleep Edge: A Protocol for Fixed Sleep Times

> Fixed sleep times are the basis of recovery. This protocol sets light, food, screens and temperature, with a weekly plan to follow.

Most sleep problems do not start in bed. They start in the afternoon with the third coffee, in the evening with bright ceiling lights and at 11 pm with the screen in your hand. A fixed bedtime does not solve that on its own, but it is the frame in which everything else takes hold. This protocol shows how to set the edge and hold it with four levers: light, food, screens and temperature. Plus a weekly plan that introduces everything within seven days.

## What the sleep edge is

An edge is a boundary that is not negotiated: a bedtime and a wake-up time that apply seven days a week. The wake-up time is the more important part. It sets the internal clock, because the first daylight sets the rhythm for the next 24 hours. If you get up at 6.30 am during the week and at 9.30 am on Sunday, you shift your clock by three hours every weekend. Monday then feels like a flight across the Atlantic. Experts call this social jetlag.

The rule for the edge: wake-up time with a maximum deviation of 30 minutes, weekends included. Choose the bedtime so that seven to eight hours remain in bed. For most adults that means lights out between 10 pm and 11 pm, up between 6 am and 7 am.

## Lever 1: Light

Light is the strongest signal for the internal clock. Two rules are enough.

Morning: within 30 to 60 minutes of getting up, 10 minutes outside, no sunglasses. An overcast sky delivers several thousand lux outdoors, a well-lit flat only 300 to 500. The window does not count, the pane filters too much. The walk to the bakery or the station counts.

Evening: two hours before lights out, ceiling lights off, only lamps below eye level with warm light. The flat should feel like a mountain hut in the evening, not like an office. The same in the bathroom before brushing your teeth: a small lamp instead of the mirror lighting.

## Lever 2: Food and drink

Caffeine has a half-life of around five to six hours. A coffee at 4 pm is still half active at 10 pm. The edge for caffeine is therefore 2 pm. That also applies to black tea, cola and most energy drinks.

The last big meal is three hours before lights out. A full stomach keeps core body temperature high and digestion active, both disturb the process of falling asleep. If you get hungry late, take a small portion: a yoghurt, a handful of nuts, a banana.

Alcohol makes you fall asleep faster and sleep worse. It suppresses REM sleep in the first half of the night and wakes you in the second. If you want to drink, drink early and little. Reduce water from two hours before bed so your bladder does not wake you at three in the morning.

## Lever 3: Screens

The screen disturbs in two ways: through the light and through the content. The light can be solved with night mode and low brightness. The content cannot. An email from the boss or a video that plays on automatically keeps the mind awake, no matter how warm the display glows.

The edge: 30 minutes before lights out, the last screen is off. The phone charges outside the bedroom or lies in flight mode in a drawer. The alarm clock is an alarm clock. Those 30 minutes belong to things without a screen: a paper book, a few notes for tomorrow, stretching, a conversation.

## Lever 4: Temperature

The body has to lower its core temperature by about one degree to fall asleep. Anything that supports that drop helps.

Bedroom at 18 degrees, cooler if in doubt. Tilt the window or air the room thoroughly for five minutes before bed. A warm shower 60 to 90 minutes before sleep works paradoxically: it widens the blood vessels in the skin and speeds up cooling afterwards. Cold feet prevent the drop in core temperature, so wear socks if needed. Choose a blanket that is light and breathable rather than heavy and warm.

## The times at a glance

Example for a wake-up time of 6.30 am:

| Edge | Time |
|---|---|
| Get up | 6.30 am, weekends included |
| Daylight outside | by 7.30 am, 10 minutes |
| Last coffee | 2.00 pm |
| Last big meal | 7.30 pm |
| Ceiling lights off | 8.30 pm |
| Screens off | 10.00 pm |
| Lights out | 10.30 pm |

If you get up later, shift all times by the same amount.

## The weekly plan: reaching the edge in seven days

Introducing everything at once usually fails on day three. So one lever is added each day and the previous ones stay.

1. Monday: set the wake-up time, set the alarm, get up when it rings. Just that.
2. Tuesday: add morning light. 10 minutes outside before work.
3. Wednesday: caffeine edge. Last coffee at 2 pm, then water or herbal tea.
4. Thursday: screen edge. Phone out of the room 30 minutes before lights out.
5. Friday: light and temperature edge. Ceiling lights off two hours before, room at 18 degrees.
6. Saturday: the test. Hold the wake-up time even though nobody demands it. This is the day the edge proves itself.
7. Sunday: review. How many nights did you manage within the 30 minutes? Four out of seven is a good start, six out of seven the goal for week three.

## When it does not work

You lie awake for 20 minutes: get up, go to another room, dim light, do something calm, back to bed when tiredness comes. The bed stays a place for sleeping, not for brooding.

You slept badly: get up at the wake-up time anyway. Sleeping in does not repair the night, it shifts the next one. A short nap of at most 20 minutes before 3 pm is allowed.

You have an exception: parties happen. The rule is to hold the wake-up time the next morning anyway and go to bed normally the night after. One exception costs a day, two in a row cost a week.

After three weeks the edge is no longer an effort but the default. Then sleep becomes what it should be: the part of the day that carries all the other parts.

## Frequently asked questions

**Do I really have to get up at the same time on weekends?**
Yes, with 30 minutes of leeway. The wake-up time is the anchor of the internal clock. Two hours of sleeping in on Sunday shift the clock so that you are not tired on Sunday evening and all the more so on Monday.

**What if I work shifts?**
Then the edge applies per shift block. Within a block, wake-up time, light and screen edge stay the same. When switching, it helps to place the morning light at the new start of the day and to darken the flat consistently before sleep.

**How long until the edge works?**
The first nights are often worse because the body does not know the new time yet. After about two weeks the rhythm stabilises, after three to four weeks many people wake up on their own shortly before the alarm.