Overview
- Published in PNAS, the modeling study estimates that permanent standard time in the U.S. could prevent about 300,000 strokes annually and lower the number of people with obesity by roughly 2.6 million compared with biannual clock changes.
- Permanent daylight time also outperforms the current system, with about 220,000 fewer strokes and 1.7 million fewer obesity cases, though the projected benefits are smaller than under standard time.
- The authors simulated indoor and outdoor light across U.S. locations and coupled circadian-response models with official health and demographic data from sources including the CDC and the census.
- Specialists call the work a pioneering population-level estimate but stress it is theoretical, assumes uniform sleep and light patterns, and may not translate directly to Spain given latitude and social differences.
- Spain and other EU countries are still scheduled to set clocks back overnight on Oct. 25–26, 2025, as discussion over abolishing seasonal changes continues.