Daylight Saving Time Doesn't Change How Much We Move, Just When We Move, Study Finds
New research using Fitbit data suggests the bi-annual clock change has a negligible effect on overall physical activity levels, but it does shift when people take their steps.
"Eliminating DST or keeping the bi-annual switch is unlikely to meaningfully affect population activity levels."
A study from Duke University, published in Nature Health on April 23, 2026, analyzed Fitbit data from the All Of Us Research Program to investigate the real-world impact of Daylight Saving Time (DST) on physical activity. By comparing step counts in Arizona—a state that does not observe DST—against neighboring states Colorado, New Mexico, and Utah, researchers sought to isolate the effect of the time change.
Key Findings: A Shift in Timing, Not Total Volume
The core finding of the study is straightforward: there was no appreciable difference in total daily steps after time changes. The total amount of walking people did remained largely the same.
However, a clear shift in when those steps occurred was observed across the board. Steps moved from the morning to the evening, or vice versa, depending on the season. This adjustment likely reflects an instinctive response to changes in daylight availability, as people shift their outdoor activities to times when the sun is up.
Who Adjusts Their Routine?
The study identified specific demographic groups that were more likely to alter their daily routines in response to the time change:
- Younger individuals
- Higher-income earners
- Those living in walkable neighborhoods
The research suggests that people with flexible schedules—such as remote workers or those with more leisure time—are better positioned to recalibrate their activity patterns. In contrast, individuals with rigid, fixed work schedules may lack the flexibility to shift their exercise or walking habits.
Implications for Society
The authors conclude that from a public health perspective, the debate over DST may be a distraction. Keeping the bi-annual switch or eliminating it entirely is unlikely to have a significant impact on population-wide activity levels.
However, the study highlights a potential fairness concern. The data suggests that individuals with less flexible work schedules—who are often lower-income or in less accommodating jobs—are less able to adapt their routines to the changing daylight. This could mean they miss out on potential benefits or face greater disruption without the ability to compensate.
The research was supported by the National Science Foundation, National Institutes of Health, and the Google Cloud Research Credits Program.