Sleep need varies more across the lifespan than almost any other physiological metric. Recommendations below are based on the National Sleep Foundation's expert panel and AASM clinical guidelines.
NEWBORNS (0–3 MONTHS): 14–17 HOURS. Fragmented into 1–4 hour stretches. Circadian rhythm undeveloped; melatonin production begins around 2–3 months.
INFANTS (4–11 MONTHS): 12–16 HOURS. Including 2–3 daytime naps. Circadian rhythm consolidates around 3–4 months. Sleep regression normal at 4, 8, and 12 months.
TODDLERS (1–2 YEARS): 11–14 HOURS. Including 1–2 naps. Bedtime resistance peaks here.
PRESCHOOLERS (3–5 YEARS): 10–13 HOURS. Most drop their nap during this window. Night terrors and sleepwalking peak here.
SCHOOL-AGE (6–13 YEARS): 9–12 HOURS. Most American children get 1–2 hours less than recommended due to early school starts. Linked to lower academic performance and higher rates of obesity, anxiety, depression.
TEENAGERS (14–17 YEARS): 8–10 HOURS. Adolescent circadian rhythm shifts 1–2 hours later — a real biological change. AAP recommends school starts no earlier than 8:30 a.m.; most US schools start earlier, producing chronic deprivation in 75% of teens.
YOUNG ADULTS (18–25 YEARS): 7–9 HOURS. Circadian rhythm remains shifted later through early 20s. Highest-risk age range for drowsy driving fatalities.
ADULTS (26–64 YEARS): 7–9 HOURS. Below 6 hours nightly = measurably higher all-cause mortality. Above 9 hours = also higher mortality (likely reverse causation).
OLDER ADULTS (65+ YEARS): 7–8 HOURS. Sleep need does NOT significantly decrease with age — the "less with age" belief is a myth. What changes is architecture: less deep sleep, more nighttime wakes.
INDIVIDUAL VARIATION. Less than 1% have a DEC2 or ADRB1 mutation allowing healthy 4–6 hour sleep. The vast majority of "short sleepers" are actually deprived.
HOW TO TELL IF YOU'RE GETTING ENOUGH. You wake naturally before your alarm. You don't need caffeine within 90 min of waking. No mid-afternoon sleepiness. Weekend sleep within 1 hour of weekday.