Secular Trends in Sleep Duration & Implications for Public Health

Abstract

Adults are believed to be sleeping less now than in the past and this “sleep loss epidemic” poses a public health dilemma because of health risks associated with short sleep durations. The current thesis aimed to determine if sleep duration has declined in recent decades. Three studies were carried out: (i) systematic literature review for evidence of secular trends in sleep duration; (ii) analysis of repeat cross-sectional data to examine changes in average sleep duration in Australia from 1992 to 2006; and (iii) analysis of time-use data from 10 countries to assess changes in prevalence of short (<6 hour) and long (>9 hour) sleep durations from 1960s to 2000s. The results show adult sleep durations are not in universal decline. Long sleep rather than short sleep appears to be increasing in the majority of countries studied. The current emphasis on short sleep overlooks the potential health impact of long sleep. Selective reporting and citation has contributed to the myth of declining sleep durations and future work needs to overcome this bias. Further studies should examine trends in sleep quality and improve the measurement of population sleep patterns.