June 7, 2023—Female health care workers who had healthier sleep prior to COVID-19 infection had a lower risk of developing long COVID than their colleagues whose sleep was less healthy, according to a new study led by Harvard T.H. Chan School of Public Health.
The study, published May 30 in JAMA Network Open, is the first to examine associations between sleep and post-COVID-19 condition (also known as long COVID), defined as experiencing COVID-19 symptoms for four or more weeks. Co-authors included Siwen Wang, research fellow in the Department of Nutrition; Andrea Roberts, senior research scientist in the Department of Environmental Health; Marc Weisskopf, professor of environmental epidemiology and physiology; and Jorge Chavarro, professor of nutrition and epidemiology.
The researchers assessed the sleep health of women enrolled in the Nurses’ Health Study II who tested positive for COVID-19 between April 2020 and November 2021. Each participant’s sleep health—which they reported on both before and during the pandemic—was given a score from zero (least healthy) to five (most healthy). Scores were based on factors like sleep duration (hours slept per night) and quality (including experiences such as insomnia, snoring, or daytime dysfunction).
Of the 1,979 participants, 870 developed long COVID. The researchers observed an inverse relationship between a long COVID diagnosis and sleep: Compared to women whose pre-pandemic sleep habits were least healthy (scoring zero or one), women whose pre-pandemic sleep habits were most healthy (scoring five, indicating quality sleep for seven to eight hours per night) had a 30% lower chance of developing long COVID.
“The findings indicate that healthy sleep measured prior to SARS-CoV-2 infection, both before and during the COVID-19 pandemic, may be protective against [long COVID],” the researchers wrote. “Future research should investigate whether interventions on sleep health may prevent [long COVID] or improve [long COVID] symptoms.”