Circadian Rhythms with 5 Clock Subsystems, Part 2: Diurnal Rhythms & Lighting

Key Takeaways

This video is part 2 of our Circadian Rhythms with 5 Clock Subsystems
It will continue to discuss how to resolve two problems: 1
At what time we are more likely to fall asleep, and how to meet the necessary conditions for falling asleep
How to stay asleep longer
So one problem is the starting point of sleep, the other is achieving a longer sleep duration

Why This Matters

This video is part 2 of our Circadian Rhythms with 5 Clock Subsystems. It will continue to discuss how to resolve two problems:

At what time we are more likely to fall asleep, and how to meet the necessary conditions for falling asleep.
How to stay asleep longer. So one problem is the starting point of sleep, the other is achieving a longer sleep duration. Part 1, discussed the 24-hour Circadian Rhythm and the 90-minute Ultradian Rhythms. Today’s video is about the Diurnal Rhythm to mark the end of sleep and to calibrate your clocks so that the clock does not drift away. We explained everything you need to know about the lighting, blue light, different kinds of light bulbs, and how to test your sunglasses. To help you to track sleep debt and sleep pressure and to create sleepiness, we discussed Homeostatic Sleep Drive. However our discussion is limited to only some of the principles of Homeostatic Sleep Drive, more details will be provided in future videos. We also have two previous videos to help solve the problem of falling asleep for people with various difficulties, initial states and skill levels. The first one, titled “Fastest ways to fall asleep with 4 states transition, Part 1: Z-state systematic analysis platform” defined 4 presleep states, including 2 new states: the Calm-State and Z-State. The second video, is based on the states defined in the first video and focuses on the Z-Loop and the sleep speedup secret, the sinking sensation. The Z-loop is one of our 5 Clock Subsystems. Timestamp Circadian Rhythms with 5 Clock Subsystems, Part 2: Diurnal Rhythms & Lighting

Understanding the Basics

The most valuable health information is practical, actionable, and based on evidence. Rather than vague advice, this guide focuses on specific techniques, measurable results, and the science that explains why they work.

The DIY Advantage

Preventive health measures and simple daily practices can reduce the need for expensive medical interventions. Understanding these practical approaches saves both money and the inconvenience of preventable health issues.

Tips for Best Results

Start with the simplest recommendation and build from there. Consistency matters more than perfection — doing something small every day is more effective than doing something elaborate once a month. Track your results so you can adjust your approach based on what works for you personally.

Video Chapter Guide

Here is a quick reference for the key sections covered in the video:

0:0 goal of this video
0:21 Diurnal Rhythm vs Circadian
0:39 Diurnal Rhythm Diagram
1:09 cortisol: caffeine 6 hours before bedtime
1:19 A. melatonin 2 hours before bedtime
1:29 B. melatonin at bedtime
1:39 C. melatonin timed-release
1:57 melatonin & light
2:14 2017 Nobel Prize blue light
2:30 remove or add blue light
2:47 blue 460-480 nm & phototoxic violet 415–455 nm
3:13 A. remove blue light with curtain or mask

Use these timestamps to jump directly to the section most relevant to your situation.

More Practical Guides

Practical health knowledge that you can apply immediately in your daily routine is more valuable than theoretical information you never act on.

For more hands-on tutorials, check out our guides on peeling garlic easily without special tools and preparing for Europe travel. Each one follows the same practical, no-nonsense approach to help you save money and build useful skills.