The Healthspan Map · Sleep (Ch6)
Sleep quality (refreshed)
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 | Watch this | Moderate | 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) |
| Balance & falls risk | Watch this | Moderate | Cohort / observational | Poor sleep quality (higher PSQI, fragmentation, daytime dysfunction) independently raises falls via impaired attention and psychomotor speed. | Sleep quality & falls nationwide study (PMC8566001) (opens in a new tab) |
| Brain fog & memory | Watch this | Moderate | 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 | Watch this | Strong | Established clinical | Non-restorative, fragmented sleep (frequent unnoticed awakenings) leaves people unrefreshed and fatigued despite adequate hours in bed. | Excessive daytime sleepiness review (AFP) (opens in a new tab) |
| Depression / low mood | Watch this | Moderate | 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) |
| Digestive discomfort | Watch this | Moderate | RCT / meta-analysis | Non-restorative sleep is bidirectionally linked with GI symptom flares. | Sleep quality & IBS (opens in a new tab) |
| Headache & migraine | Watch this | Moderate | 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 | Watch this | Moderate | 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) |
| High blood pressure | Watch this | Moderate | RCT / meta-analysis | Insomnia symptoms and disturbed sleep raise hypertension risk; untreated sleep apnea is a major cause of high blood pressure. | Sleep/insomnia & hypertension meta (opens in a new tab) |
| Muscle & joint pain / weakness | Watch this | Moderate | Review / narrative | Most muscle repair happens in deep (slow-wave) sleep, when the growth-hormone pulse peaks; fragmented, poor-quality sleep loses deep sleep first and blunts recovery. | Sleep & muscle recovery review (opens in a new tab) |
| Osteoporosis / low bone density | Watch this | Moderate | RCT / meta-analysis | Undisturbed, dark sleep drives melatonin, which promotes bone-building osteoblasts and curbs bone-resorbing osteoclasts; poor-quality sleep and light at night suppress it. | Melatonin & bone meta (opens in a new tab) |
| Peripheral neuropathy | Watch this | Emerging | RCT / trial | Nerve-pain patients have fragmented, unrefreshing sleep; better sleep quality helps pain and function. | Neuropathic pain & sleep (opens in a new tab) |
| Reproductive & sexual health | Watch this | Moderate | Cohort / observational | Fragmented sleep and obstructive sleep apnea are independently associated with lower testosterone, impaired semen quality and erectile dysfunction that improves when OSA is treated. | OSA & male reproductive function (PMC12483905) (opens in a new tab) |
| Respiratory infections & airway health | Watch this | Strong | RCT / trial | Sleep efficiency below 92% predicted 5.5× higher odds of developing a cold after viral exposure, in graded fashion. | Sleep habits & susceptibility to the common cold (Cohen, Arch Intern Med 2009) (opens in a new tab) |
| Skin, hair, nails & wound healing | Watch this | Strong | Established clinical | Poor sleepers had double the intrinsic skin-ageing score and 30% less skin-barrier recovery at 72 h (higher TEWL). | Sleep quality & skin ageing (opens in a new tab) |
| Stress | Watch this | Moderate | Established clinical | Poor sleep quality amplifies amygdala reactivity and perceived stress; good-quality sleep buffers stress sensitivity. | Sleep quality & amygdala/perceived stress (opens in a new tab) |
| Thyroid dysfunction | Watch this | Emerging | Review / narrative | Poor sleep quality correlates with elevated TSH/T4 and, via HPA-axis/cortisol activation, can disturb the hypothalamic–pituitary–thyroid axis. | Thyroid dysfunction & sleep quality study (PMC11144793) (opens in a new tab) |
| Tinnitus | Watch this | Moderate | Cohort / observational | Reduced sleep quality is consistently associated with bothersome tinnitus. | Tinnitus & sleep quality (opens in a new tab) |
| Type 2 diabetes & metabolic syndrome | Watch this | Moderate | RCT / meta-analysis | Poor sleep quality and fragmentation (including sleep apnea) worsen insulin sensitivity and raise diabetes risk. | Sleep & T2D risk meta (opens in a new tab) |
| Vision problems | Watch this | Moderate | Review / narrative | Unrefreshing sleep is the hallmark of OSA, consistently linked to floppy eyelid syndrome, ischemic optic neuropathy, diabetic macular oedema and other retinal changes. | Sleep & eye disease review (PMC9544516) (opens in a new tab) |
| Weak immunity & chronic inflammation | Watch this | Strong | RCT / meta-analysis | Poor sleep efficiency raises cold susceptibility and CRP/IL-6 (Cohen; AASM consensus). | Sleep quality & infection (opens in a new tab) |
| General / Whole-body Energy | Watch this | Strong | Established clinical | Poor sleep quality is strongly associated with fatigue, physical complaints and reduced quality of life. | Pittsburgh Sleep Quality Index review (Occupational Medicine 2025) (opens in a new tab) |
| Neurological & Mental Health | Watch this | Moderate | RCT / meta-analysis | Poor sleep quality raises risk of depression, anxiety and cognitive dysfunction. | Sleep-quality and mental-health meta-analyses (opens in a new tab) |
| Liver, Kidney & Urinary | Watch this | Moderate | Systematic review | Obstructive sleep apnea (fragmented, unrefreshing sleep) is independently associated with kidney impairment and with hepatic steatosis. | OSA & renal impairment meta-analysis (PMC7987709) (opens in a new tab) |
The Healthspan Map is part of Fix the Floor, a book by Aamir Malik. About the book