We all have an inner clock — what doctors call circadian rhythm. It’s the body’s 24-hour cycle. Cell Reports Methods

Circadian rhythm has wide-ranging health implications. It plays a critical role in regulating functions including hormone levels; quality and quantity of sleep; and weight, eating and digestion. 

And soon, our everyday wearables may unlock its secrets.

Researchers at the University of Michigan recently created a statistical method to extract the circadian rhythm in heart rate from data collected on wearables such as the Apple Watch, Fitbit, and Mi Band. 

The potential for this information is significant. Giving individuals and doctors access to circadian rhythm data could facilitate the detection of a change in health status and aid in early diagnosis. It could also inform doctors’ personalized recommendations for timing medications, improving sleep, supporting weight management, optimizing the impact of fitness training, and more. 

The ability to easily identify an individual's circadian rhythm has important implications for medicine. But, it’s been challenging and expensive to study it at a population level and in real-world situations. Until now.

In the study, scientists analyzed 130,000 days of real-world sleep, heart rate, and motion data from wrist-based sleep-tracking devices on more than 900 people. Using a statistical method called Bayesian uncertainty quantification, they found they could estimate an individual's circadian rhythm in heart rate, the daily cycle in heart rate independent of acute activity and sleep. With the data, researchers demonstrated they could measure adaptive adjustments in the daily rhythm in response to real-world stimuli, such as changes in sleep schedule. 

This is yet another great example of household-grade technology empowering highly personalized medicine, with the potential to help millions of people live healthier lives. The HealthTap primary care team looks forward to the opportunity to work with patients to better understand their inner clock, and improve their health and wellbeing.

If you’re struggling with sleeplessness or any of the conditions mentioned above, I encourage you to reach out to your primary care doctor for help. Don’t have a doctor? Get a great one with HealthTap. Our virtual primary care clinic is available in all 50 states and HealthTap members pay only $39 per visit. You choose your own doctor and see them for all your visits.