Your oral bacteria may reveal how long you sleep

According to new research on adolescents and young people in the United States, trillions of bacteria that live in your mouth may match the clues of your sleeping habits.

Scientists have found that sleeping much more time than recommended oral microorganisms for people, a discovery that opens an unexpected window to the complex relationship between sleep and the microecosystem.

The study tracked 1,332 participants aged 16 to 26, indicating that 3% of the reported prolonged periods of sleep showed significantly different oral bacterial patterns compared to healthy sleep habits. The finding marks the first time that researchers have linked the diversity of the oral microbiome to the way adolescents sleep, a critical developmental period in which sleep and oral health experience significant changes.

Beyond the Intestine: New Microbial Frontiers

“For two decades, researchers hypothesized that the microbiome was largely seen as a determinant of health and disease,” explains Marie-Rachelle Narcisse, assistant professor at the Warren Alpert Medical School at Brown University. Although most microbiome studies focus on gut bacteria, the study shifted attention to the mouth, one of the most dense microbial habitats in the human population.

The human mouth occupies hundreds of bacterial species in a delicate balance. These microcommunities not only affect dental health; they are gatekeepers at the entrance of the human body, affecting everything from immune function to the entire body’s inflammation level.

The numbers tell a story

The team analyzed the data from the National Health and Nutrition Examination Survey and studied four different measures of microbial diversity. They found that adolescents and young people who sleep longer than recommended showed higher diversity among three key indicators:

• 43 More Operational Taxonomy (Measurement of Bacterial Varieties)
• Phylogenetic diversity score nearly three points
• 0.64 Shannon-Weiner index value

But here’s what’s interesting: According to the American College of Sleep Medicine guidelines, about half of teenagers (50.6%) and ten young people (61.2%) reported healthy sleep durations, but only a small percentage of them experienced prolonged sleep. AASM recommends 8-10 hours for teenagers and 7-9 hours for young people.

The Big Picture: What does the abstract reveal

In-depth research shows that key background is missing in the initial report. The study adjusted for complex investigation design factors and controlled for multiple variables when examining the relationship between sleep and oral microbiome diversity. This approach strictly enhances the reliability of discovery.

Perhaps more interesting is that researchers use complex indices to measure diversity that not only capture how many different bacterial species exist, but also their evolutionary relationships and relative abundance. The reverse Simpson index (the only measure that did not show a significant correlation with sleep duration) specifically examines the dominant patterns of species, which suggests that while long-sleepers have more bacterial changes, none of a single species overwhelmingly occupying its oral ecosystem.

A two-way street?

These findings raise the question of chickens and eggs: Will changing sleep change the oral microbiome, or will certain bacterial communities affect sleep patterns? Deficiency of sleep can weaken immune function and increase inflammation and may produce diseases in which different bacterial populations reproduce. In contrast, oral bacteria produce various metabolites that may theoretically affect the sleep regulation system.

“Our findings suggest that improving sleep health in adolescents, or conversely, improving sleep to affect the oral microbiome is expected to provide more accessible and cost-effective intervention strategies,” Narcisse noted.

Why is adolescence important

Attention to teenagers and young people is not arbitrary. Adolescence brings a drastic change in the sleep effect cycle, driven by the biological changes that make natural night owls in adolescents. This is also the time when oral health habits solidify or worsen. Understanding how these two systems interact during this critical period can inform interventions that benefit long-term health.

Consider a typical teenager: staying up late to scroll through social media, maybe ignoring the night teeth, and then sleeping on weekends until noon. Each of these behaviors can affect the oral bacterial community in a way that we only begin to understand.

expect

This study, supported by the National Institute of General Medical Sciences, represents only the beginning. Scientists need to determine whether these associations persist in longitudinal studies and whether interventions targeting sleep or oral bacteria can improve overall health.

At present, this information is still subtle. While maintaining recommended sleep time and good oral hygiene, this study reminds us that our bodies’ systems are interconnected in surprising ways. The bacteria in the mouth may learn more about your sleeping habits than you think, and understanding how connections can unlock new ways of teenage health.

The findings will be held in Seattle on June 10 in the same professional sleep society’s annual conference 2025 Sleep.