Sleep

SummaryFactor descriptionImpact on all-cause mortalityPatternsKamaLama scoringPractical tipsReferences

Summary

  • Sleep supports survival by helping the brain, hormones, metabolism, immune system, and heart recover each day.
  • In adults aged 50–75, sleeping about 7–8.5 hours/night is linked to about 19.1 years in good health (and 13.5 years without chronic disease) between ages 50 and 75.
  • Short (<7 h) or long (≥9 h) sleep is linked to about 1–3 fewer healthy and disease-free years in this age range.
  • Severe sleep disturbances are linked to up to ~6 fewer healthy years (and ~3 fewer disease-free years) between ages 50 and 75.
  • Large meta-analyses show a U-shaped pattern for all-cause mortality: both short and long sleep are linked to higher death risk compared with mid-range sleep.

Factor description

This factor measures your typical sleep pattern over time, including:

  • Sleep duration: how many hours you usually sleep per night (average across a typical week, not just one night).
  • Sleep regularity: how stable your bed and wake times are from day to day.
  • Sleep disturbances: whether sleep is often disrupted (for example, insomnia symptoms, frequent awakenings, breathing-related problems such as loud snoring or pauses in breathing, or strong daytime sleepiness).

Sleep can be measured by self-report (what you say you usually sleep) or by devices (wearables/actigraphy). Device-based measures can capture timing and regularity more precisely, but many large studies use self-report.

Impact on all-cause mortality

  1. Sleep duration shows a U-shaped risk pattern
  • Across many long-term cohort studies, the lowest all-cause mortality risk is usually around 7–8 hours per night.
  • Habitual short sleep and habitual long sleep are both linked to higher mortality risk.
  • Short sleep can raise risk through higher blood pressure, worse glucose control, weight gain, inflammation, and mental health effects.
  • Long sleep is often linked to higher mortality in studies, but part of this can reflect underlying illness, depression, frailty, or low activity (reverse causation).
  1. Sleep disturbances reduce years lived in good health
  • Disturbed sleep is linked to fewer years of healthy life and fewer years free from chronic disease.
  • Severe and persistent problems (especially when combined with short sleep) show the largest reductions in healthy years.
  1. Cardiovascular pathways are a major link to all-cause mortality
  • Poor sleep health is associated with fewer cardiovascular disease (CVD)–free years.
  • Sleep-disordered breathing (for example, obstructive sleep apnea patterns) can strongly increase cardiometabolic stress (intermittent low oxygen, surges in blood pressure, inflammation), which raises risk of CVD events that contribute to all-cause mortality.
  1. Sleep regularity adds independent information beyond hours
  • Irregular sleep timing (shifting bed/wake times) predicts higher all-cause mortality even after accounting for sleep duration.
  • Practically, a stable schedule plus a reasonable duration often performs better than perfect “hours” with chaotic timing.
  1. Causal evidence is strongest for short sleep
  • Genetic (Mendelian randomisation) evidence suggests that a tendency toward short sleep is likely a causal risk factor for shorter lifespan, not only a marker of poor health.
  • For insomnia symptoms without short sleep, causal signals can be weaker or less consistent, suggesting sleep duration and chronic restriction may be especially important.

Patterns

  • Age: sleep becomes lighter and more fragmented with age, and sleep disturbances are more common in older adults.
  • Work schedule: shift work and irregular hours increase irregular sleep timing and can shorten sleep.
  • Health status: chronic pain, depression/anxiety, cardiometabolic disease, and some medications commonly worsen sleep.
  • Sleep-disordered breathing risk: breathing-related sleep problems are more common with older age and higher body weight, and can occur in any sex.
  • Social and environmental factors: stress, long commutes, noisy/light environments, and crowded housing can reduce sleep duration and regularity.

KamaLama scoring

KamaLama uses a hybrid scoring logic:

  • Duration has a U-shaped pattern (both too little and too much are linked to higher risk).
  • Disturbances and irregular timing add extra risk beyond hours alone.
  • Scores are based on long-term patterns (what you do most weeks), not occasional bad nights.
  • Categories reflect increasing deviation from a stable, mid-range, good-quality sleep profile.
Category/RangeScore (in years)
Optimal0 years (reference)
Slightly suboptimal−0.3 to −0.8 years
Clearly suboptimal−0.8 to −1.8 years
High-risk sleep profile−1.8 to −3.0 years

Practical tips

  • Start with timing: choose a consistent wake time (even on weekends), then move bedtime earlier to match it.
  • Protect the last hour before bed: dim lights, reduce screens, and do one calming routine (shower, stretching, reading, breathing).
  • Use caffeine strategically: avoid caffeine late in the day (many people do better with no caffeine after lunch).
  • Make the bedroom “sleep-first”: cool, dark, quiet, and phone out of reach.
  • If you wake up often, focus on the basics first: regular schedule, morning daylight, daily movement, and fewer late heavy meals/alcohol.
  • If you snore loudly, gasp, or feel very sleepy in the daytime, consider screening for sleep apnea (treating it can improve health risks).
  • If insomnia lasts weeks and affects daytime function, evidence-based insomnia treatment (CBT-I) is often more effective long-term than relying on sleep pills.

References

This website is for informational purposes only and not a substitute for medical advice.
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