Over 70 million Americans wear fitness trackers to monitor steps, sleep, and heart rate. A new study suggests these popular devices could soon do even more—like help detect serious health risks, including sleep apnea and high blood pressure.
Researchers from Scripps Research found that night-to-night changes in when people fall asleep and wake up—known as sleep variability—may reveal if they’re at higher risk for obstructive sleep apnea or hypertension. The study was published in the Journal of Medical Internet Research.
The lead author, Dr. Stuti Jaiswal, says this kind of data could offer a unique way to find important health patterns without needing new devices.
“Digital health research is becoming more accepted,” Jaiswal explains. “This shows that information from everyday wearables could be used to understand how sleep affects heart health.”
Sleep apnea is a common condition that causes repeated pauses in breathing while asleep, due to relaxed airway muscles. It affects around 50 million Americans and increases the risk of heart problems, stroke, and other serious conditions.
High blood pressure, or hypertension, is also widespread—nearly half of U.S. adults have it. Left untreated, it raises the risk of heart attacks and heart failure. Being able to detect early signs of these conditions using fitness tracker data could lead to earlier treatment and better outcomes.
To conduct the study, the research team created a digital trial called REFRESH (Research Framework for Exploring Sleep Health). They recruited over 1,000 adults from across the country, asking them to share sleep data from their fitness trackers and complete health surveys.
For this part of the study, the team focused on about 400 people who had at least two years of sleep data. Most participants used Fitbit devices, which have been widely used in sleep research. The data included sleep patterns, bedtime habits, and survey results on their risk for sleep apnea.
The researchers discovered a strong connection between sleep variability and health risks. People whose bedtimes varied by just one hour from night to night were more than twice as likely to have sleep apnea. They were also 71% more likely to have high blood pressure compared to those with consistent sleep schedules.
These findings show that even small changes in sleep timing can have a big impact on health. It also highlights the power of long-term data collected from wearables. Although more research is needed to understand why this happens, the connection is clear.
Dr. Natalia Orendain, the study’s first author, said this type of research shows how consumer devices could become powerful tools for early detection of disease. “These devices can track data over time and help identify hidden risks,” she noted.
The study also challenges the idea that total sleep time is the only thing that matters. While getting seven to nine hours of sleep is important, having a regular bedtime may be just as critical. Irregular sleep can disrupt hormones, increase inflammation, and affect metabolism—all of which contribute to heart disease.
Dr. Jaiswal says the next step is learning how to help people improve their sleep patterns using these findings. The team also hopes to study how sleep data connects to mental health conditions like depression and anxiety.
In the future, data from fitness trackers could play a role in personalized healthcare. Instead of relying only on traditional tests, doctors might also use real-time sleep and activity data to spot risks early and guide lifestyle changes.
This research offers hope that wearable technology could do more than track steps—it might help save lives by identifying health issues before symptoms even begin.
If you care about high blood pressure, please read studies about breakfast for better blood pressure management, and the gut feeling that lowers blood pressure.
For more health information, please see recent studies about how the dash diet helps lower blood pressure, and how to eat your way to healthy blood pressure.
Copyright © 2025 Knowridge Science Report. All rights reserved.
