A composite measure of healthy sleep—which captured not just how long people sleep but how well and how consistently—is associated with a substantially lower risk of pneumonia, according to a long-term cohort study published this week in Open Forum Infectious Diseases.
For the prospective analysis, Chinese researchers examined health data from 361,589 adults in the United Kingdom. Those with the healthiest overall sleep patterns had a 26% lower risk of developing pneumonia over roughly 13 years of follow-up than those with the poorest sleep profiles.
Pneumonia risk falls as sleep quality rises
Five sleep characteristics—duration, chronotype (being a “morning person” vs an “evening person”), insomnia symptoms, snoring, and daytime sleepiness—were used to determine an overall sleep score of 0 to 5. Participants were then grouped into poor (0 to 1), intermediate (2 to 3), and healthy (4 to 5) sleep score categories.
Over the study period, 20,116 participants (5.6%) developed pneumonia. The findings showed that risk decreased as sleep improved. Those with the healthiest sleep profiles had the lowest risk of developing pneumonia overall, while those with intermediate scores had modestly lower risk, and those with poor scores had the highest risk.
The findings also suggest that different aspects of sleep are associated with respiratory infection risk in specific ways. People who didn’t often feel sleepy during the day had a lower risk of pneumonia (hazard ratio [HR], 0.79), as did those who didn’t experience frequent insomnia symptoms (HR, 0.88). Being a “morning person” was also associated with a lower risk (HR, 0.93).
Hitting the sweet spot in sleep duration
Sleep length mattered, too. The lowest risk was seen in people who slept seven to eight hours per night. Sleeping less than seven hours (HR, 1.15) or more than 8 hours (HR, 1.29) was linked to a higher risk of pneumonia, forming a U-shaped pattern. Snoring didn’t appear to affect pneumonia risk (HR, 1.00).
The link between healthy sleep and lower pneumonia risk was more pronounced in adults younger than 60 and in women, findings that “should be interpreted cautiously, but may be consistent with evidence that younger adults exhibit greater immunological responsiveness to sleep variation before the onset of age-related immunosenescence [gradual weakening of the immune system], and that associations between sleep disturbance and inflammatory responses are, in some settings, stronger in women.”
They team didn’t find any evidence that factors like body weight, smoking, exercise, diet quality, or having multiple health conditions changed the relationship between sleep and pneumonia risk.
Poor sleep may weaken immune function
Sleep plays a central role in immune function, and disrupted or insufficient sleep has been linked to impaired immune responses, altered inflammatory signaling, and reduced ability to fight infections, all of which could increase susceptibility to respiratory illnesses like pneumonia, the study authors said.
The study had some limitations. Sleep variables were self-reported, and some potential confounding factors, such as differences in vaccination status, were unknown.
Even so, write the researchers, while the findings shouldn’t be interpreted as proof that modifying sleep can reduce pneumonia risk, they “suggest that multidimensional sleep assessment may complement established risk factors in identifying individuals at potentially higher respiratory infection risk.”
