The study of smart-bed sleepers found that there was a statistically significant correlation between a higher number of episodes of influenza-like illnesses (ILI) per year with longer duration compared to people without insomnia.
However, more research is needed to determine causality and whether insomnia may predispose to ILI or whether ILI affects long-term sleep behavior, the researchers noted.
“Several lines of evidence make me think that it’s more likely that insomnia makes one more vulnerable to influenza through pathways that involve decreased immune function,” study investigator Gary Garcia-Molina, PhD, with Sleep Number Labs, San Jose, Calif., said in an interview.
Sleep disorders, including insomnia, can dampen immune function and an individual’s ability to fight off illness, he noted.
The findings were presented at the annual meeting of the Associated Professional Sleep Societies.
Smart, connected devices
Pathophysiological responses to respiratory viral infection affect sleep duration and quality in addition to breathing function. “Smart” and “connected” devices that monitor biosignals over time have shown promise for monitoring infectious disease.
In an earlier study presented at SLEEP 2021, Dr. Garcia-Molina and colleagues found that real-world biometric data obtained from a smart bed can help predict and track symptoms of COVID-19 and other respiratory infections. They showed that worsening of COVID-19 symptoms correlated with an increase in sleep duration, breathing rate, and heart rate and a decrease in sleep quality.
In the new study, the researchers evaluated vulnerability to ILI in people with insomnia.
They quantified insomnia over time using the insomnia severity index (ISI). They quantified ILI vulnerability using an established artificial intelligence model they developed that estimates the daily probability of ILI symptoms from a Sleep Number smart bed using ballistocardiograph sensors.
Smart bed data – including daily and restful sleep duration, sleep latency, sleep quality, heart rate, breathing rate and motion level – were queried from 2019 (pre-COVID) and 2021.
A total of 1,680 smart sleepers had nearly constant ISI scores over the study period, with 249 having insomnia and 1,431 not having insomnia.
Data from both 2019 and 2021 show that smart sleepers with insomnia had significantly more and longer ILI episodes per year, compared with peers without insomnia.
For 2019, individuals without insomnia had 1.2 ILI episodes on average, which was significantly less (P < .01) than individuals with insomnia, at 1.5 episodes. The average ILI episode duration for those without insomnia was 4.3 days, which was significantly lower (P < .01) in those with insomnia group, at 6.1 days.
The data for 2021 show similar results, with the no-insomnia group having significantly fewer (P < .01) ILI episodes (about 1.2), compared with the insomnia group (about 1.5).
The average ILI episode duration for the no-insomnia group was 5 days, which was significantly less (P < .01) than the insomnia group, at 6.1 days.
The researchers said their study adds to other data on the relationship between sleep and overall health and well-being. It also highlights the potential health risk of insomnia and the importance of identifying and treating sleep disorders.
“Sleep has such a profound influence on health and wellness and the ability to capture these data unobtrusively in such an easy way and with such a large number of participants paves the way to investigate different aspects of health and disease,” Dr. Garcia-Molina said.