The Healthspan Map · Sleep (Ch6)
Sleep hygiene - Clock & light
Compiled by Aamir Malik, PhD, Professor of Neuroengineering at Brno University of Technology, from published studies. He is a researcher, not a physician. Last updated 21 August 2026.
What this is linked to
| Condition or system | Direction | Strength | Evidence type | What was found | Source |
|---|---|---|---|---|---|
| Anxiety | Do this | Emerging | RCT / meta-analysis | Poor/short sleep and anxiety are bidirectionally linked; better sleep lowers physiological arousal. | De Nys et al. 2022 (opens in a new tab) |
| Brain fog & memory | Do this | Emerging | Systematic review | Sleep deprivation impairs attention and working memory; 7-8 h is optimal for cognition. | Sleep-cognition overview 2023 (opens in a new tab) |
| Chronic fatigue / low energy | Do this | Emerging | Cohort / observational | Consistent light/dark timing anchors the circadian clock and next-day alertness. | Morning light & sleep/alertness field study (PubMed 36058557) (opens in a new tab) |
| Depression / low mood | Do this | Emerging | RCT / meta-analysis | Insomnia roughly doubles the risk of developing depression (OR 2.60); a core modifiable risk factor. | Baglioni et al. 2011 (opens in a new tab) |
| Headache & migraine | Do this | Emerging | RCT / meta-analysis | Irregular sleep is a major migraine trigger; consistent sleep-wake schedules are a cornerstone of prevention. | Robblee & Starling 2019, Cleveland Clinic J Med; lifestyle-migraine meta 2024 (opens in a new tab) |
| Headache & migraine | Do this | Emerging | Review / narrative | Irregular sleep is a major migraine trigger; consistent sleep-wake schedules are a cornerstone of prevention. | Robblee & Starling, "SEEDS for success: Lifestyle management in migraine", Cleve Clin J Med 2019 (opens in a new tab) |
| Insomnia / poor sleep | Do this | Strong | RCT / trial | Light is the dominant melatonin synchronizer; blue/bright evening light suppresses melatonin, dim light and a dark room preserve it. | Evening light-melatonin studies (opens in a new tab) |
| Stress | Do this | Emerging | RCT / meta-analysis | Poor sleep and elevated stress are bidirectionally linked; better sleep associates with lower cortisol. | De Nys et al. 2022 (physical activity, cortisol & sleep) (opens in a new tab) |
The Healthspan Map is part of Fix the Floor, a book by Aamir Malik. About the book