Overview
- In a Jan. 27 interview on Spain’s Hoy por Hoy, chronobiologist Juan Antonio Madrid advised an optimal nightly range of roughly 6.5 to 8.5 hours.
- Madrid said sleeping under six hours has medium- and long-term harms and cited studies suggesting those regularly getting 10 to 12 hours may face higher mortality.
- Coverage referenced the Framingham Heart Study, which found people sleeping more than nine hours were more likely to develop dementia than those sleeping less.
- Alzheimer’s Research UK’s Dr Rosa Sancho noted that altered sleep can precede symptoms, reinforcing that changes may be early markers rather than proven causes.
- Madrid emphasized sleep quality and regularity, noting normal hourly micro-awakenings, evidence linking consistent schedules to longevity, and that naps do not replace night sleep.