Study suggests most Americans would be healthier without daylight saving time

- Daylight Saving Time (DST) is the US practice of setting clocks forward one hour in spring and back in fall, observed March–November. "Standard time" (winter clocks) aligns noon closer to the sun's peak; DST shifts daylight later into evening. - The core debate: DST disrupts the body's circadian rhythm, which is primarily set by morning light. Permanent DST would mean dark winter mornings; permanent standard time would mean lighter mornings but darker summer evenings. - Prior research links the spring "spring forward" to short-term spikes in heart attacks, strokes, and traffic accidents from sleep loss. - Most US states have proposed switching to permanent DST or permanent standard time, but federal law only permits DST's current March–November window unless Congress acts. - This Stanford study adds population-level health evidence to the policy debate, arguing year-round standard time is better for sleep and cardiometabolic health.