Sleep and the Common Cold

Sleep deprivation can adversely affect immune function, and one study has suggested a link between poor sleep habits and increased risk for common colds (JAMA 1997; 277:1940). Researchers now report results from a prospective study of sleep habits and rhinovirus susceptibility.

Participants were interviewed daily for 14 days to assess sleep duration and “sleep efficiency” (the proportion of time in bed spent asleep). Information on several other variables (e.g., rhinoviral antibody titers, age, body-mass index, race, income, sex, smoking) was also collected to allow control for potential confounders. After this assessment, participants were placed in quarantine, exposed to an experimental rhinovirus (RV-39), and monitored for 5 days for signs and symptoms of illness. The outcome (a cold) was defined as infection (recovery of RV-39 from nasal lavage fluid or a ≥4-fold rise in RV-39 antibody titer) plus the presence of signs (mucus weight ≥10 g or nasal clearance time ≥35 minutes) or symptoms of a cold.

Of 153 individuals enrolled, 135 (88%) became infected, but only 54 (35%) and 66 (43%) developed a cold as determined by signs and by symptoms, respectively. Participants who averaged <7 hours of sleep per night had the highest risk for colds as determined by signs (odds ratio, compared with participants sleeping ≥8 hours/night, 2.9; 95% confidence interval, 1.2–7.3). Similarly, those with “sleep efficiency” <85% had the highest risk for colds after RV-39 exposure (OR, compared with the rest of the sample, 5.4; 95% CI, 1.5–19.1).