Literacy development and sleep habits across the second-grade school year

Second grade is a key period in reading acquisition, when children consolidate decoding and strengthen orthographic, phonological, and semantic representations through sustained instruction and practice. Because sleep is linked to learning and memory consolidation in childhood, we examined whether children’s self-reported sleep habits are reflected in literacy levels and within-year literacy growth in a socioeconomically disadvantaged school context. Participants were 309 Hebrew-speaking second graders from five public schools, assessed at the beginning (T1) and end (T2) of the school year. Sleep habits were measured with the Sleep Self-Report (SSR); children were classified at T1 as poor sleepers or good sleepers using k-means clustering on three SSR subscales (bedtime behavior, sleep behavior, daytime sleepiness). Literacy performance included orthographic word identification, phonological decoding, reading comprehension, spelling, and vocabulary in pointed Hebrew. Over the year, total sleep problems, bedtime behavior, and sleep behavior improved, with greater improvement among poor sleepers, whereas daytime sleepiness showed no measurable change. All literacy outcomes improved from T1 to T2, but neither overall literacy levels nor within-year literacy gains differed by sleep group. Together, the findings suggest that during second grade, when reading development is strongly driven by ongoing practice and consolidation of foundational skills in Hebrew, sleep-profile differences captured by child self-report may be less likely to translate into differentiated literacy development over a single school year. These findings should be interpreted cautiously, as sleep was assessed only through child self-report, and associations with literacy might differ if caregiver reports or other indicators such as actigraphy were used.