For decades, napping research has relied on a deceptively simple question: do you nap or not? In a new perspective piece published in Sleep Health, chronobiology researcher Marta Garaulet (University of Murcia, Brigham and Women’s Hospital/Harvard) and co-author M. Rodriguez-Martin argue that this binary approach obscures the complex relationship between daytime sleep and health outcomes. The field, they contend, must move toward a multidimensional phenotyping framework that captures the full variability of human napping behavior.
The authors propose that napping should be characterized across at least four core dimensions: frequency, duration, timing, and individual differences. A 15-minute power nap taken daily at noon is biologically and behaviorally distinct from a two-hour afternoon sleep that occurs only on weekends, yet both are simply labeled napping in most survey instruments. These distinctions matter because each nap phenotype may carry different implications for circadian alignment, metabolic health, and recovery.
The framework connects directly to Garaulet’s broader research on circadian rhythms and obesity. Napping timing, in particular, may reflect underlying chronotype and circadian phase. Afternoon sleep that aligns with the post-lunch dip in alertness may be physiologically adaptive, while napping at other times could signal circadian disruption. Duration also plays a key role: short naps (under 30 minutes) have been linked to improved cognitive performance, while longer naps have been associated with metabolic risks in some epidemiological studies.
A distinctive feature of the piece is its attention to the siesta as a culturally embedded nap phenotype. In Mediterranean and many Latin American societies, the siesta is not an occasional indulgence but a structured, socially sanctioned period of daytime rest. The authors argue that studying the siesta phenotype specifically can illuminate how cultural norms shape the health effects of napping, offering a natural experiment that binary yes/no measures would miss.
The implications extend to precision health. If napping phenotypes differ in their associations with obesity, cardiovascular risk, and cognitive function, then personalized sleep recommendations require richer characterization than current tools provide. A one-size-fits-all recommendation to nap or not to nap may be as outdated as recommending the same sleep duration for everyone.
The authors call for new measurement instruments and analytical approaches that treat napping as a continuous, multidimensional behavior rather than a binary trait. No conflicts of interest were declared.
Citation: Garaulet M, Rodriguez-Martin M. Beyond yes or no napping: From binary nap definitions to multidimensional phenotyping of daytime sleep. Sleep Health. 2026 Jul 10. doi: 10.1016/j.sleh.2026.06.002. PMID: 42431814