Clocks Fall Back as DST Ends, Health Experts Favor Standard Time

Most of the United States will set clocks back one hour at 2 a.m. local time Sunday as daylight saving time ends, effectively shifting most of the country into standard time and giving people an extra hour of sleep overnight. The change will remain in place until March 8, when clocks spring forward again, and it comes amid debate over the health and safety effects of the twice yearly shift.

Scientists and major medical groups increasingly say the onetime change is disruptive to the body's internal clock and that permanent standard time would be healthier than switching back and forth. New research from Stanford University, along with positions from organizations including the American Medical Association and the American Academy of Sleep Medicine, found that avoiding the biannual transitions is better for public health and that yearround standard time most closely aligns with human circadian rhythms. Jamie Zeitzer, co director of Stanford's Center for Sleep and Circadian Sciences, said, "More light in the morning and less at night is key to keeping that rhythm on schedule all the instruments in sync."

Human sleep and alertness are governed by a roughly 24 hour circadian rhythm...