Researchers at the University of Michigan have identified a bidirectional relationship between daily physical activity and mood stability in adults living with bipolar disorder.
The study, published inNPP—Digital Psychiatry andER Neuroscience, tracked 252 participants over 12 months using a combination of smartphone mood surveys and Fitbit wearable technology.
Using data from the PROviding Mental Health Precision Treatment study, the team analyzed how changes in steps, high-intensity activity, and resting heart rate correlated with daily emotional states.
The activity-mood loop
The researchers found a small but credible feedback loop between daily step counts and emotional wellbeing. Specifically, individuals who reported a better mood than their personal average tended to take more steps the following day. Conversely, higher step counts often preceded better mood ratings.
While the study also tracked 'very active minutes'—periods of higher-intensity exercise—the results were one-sided. Higher-intensity activity predicted a better mood the next day, but the researchers did not find a corresponding reverse effect where intense exercise led to more frequent high-intensity sessions later.
Data from the Fitbit devices also tracked resting heart rate (RHR), but no significant link emerged between heart rate fluctuations and daily mood changes. The study did note that participants with higher baseline anxiety levels experienced more significant daily variability in their resting heart rate.
By using 'digital phenotyping'—the passive collection of data via sensors—the researchers were able to observe these patterns in real-world settings rather than in a controlled clinical environment. The findings suggest that maintaining regular daily movement, particularly total step counts, may serve as a practical tool for mood regulation in bipolar disorder management.
