This Sunday, clocks across most of the United States will jump ahead one hour as daylight saving time begins. While losing an hour of sleep might seem like a minor inconvenience, medical experts warn the effects extend far beyond feeling groggy Monday morning.
The shift to earlier sunrises and extended evening daylight disrupts your internal body clock, potentially triggering sleep problems that can persist for weeks. Medical research has documented increases in heart attacks and strokes immediately following the March time adjustment.
However, there are strategies to minimize the transition’s impact, such as seeking morning sunlight exposure to help recalibrate your body’s natural sleep-wake cycle.
At 2 a.m. Sunday, most Americans will lose an hour as daylight saving time officially starts. The change reverses on November 1 when clocks move backward an hour.
Several areas don’t participate in the time shift, including Hawaii, most of Arizona, Puerto Rico, American Samoa, Guam, and the U.S. Virgin Islands, which maintain standard time throughout the year. Many nations worldwide also practice daylight saving time, though their start and end dates vary.
While some individuals attempt to prepare by retiring slightly earlier for several nights beforehand, the adjustment proves particularly challenging for the one-third of American adults who already fall short of the recommended seven hours of nightly rest.
Your brain contains a master timekeeper that responds to light and darkness exposure. This internal rhythm operates on approximately a 24-hour schedule, controlling when you feel sleepy versus alert. These patterns shift with age, explaining why young children who wake early often become teenagers who struggle to get up.
Sunlight exposure in the morning resets this internal clock. As evening approaches, your body increases production of melatonin, a hormone that promotes sleepiness. Extended daylight from the time change interferes with this melatonin release, throwing the entire system off balance.
Insufficient sleep connects to cardiovascular disease, mental decline, weight gain, and many other health issues. Your circadian rhythm influences more than just sleep, affecting heart rate, blood pressure, stress hormone levels, and how your body processes food.
Research examining U.S. traffic deaths shows a temporary spike in fatal accidents during the initial days after the spring time change. Morning crashes showed the highest increase, which scientists linked to sleep loss.
Cardiovascular risks also rise during this period. The American Heart Association references studies indicating more heart attacks occur on the Monday following daylight saving time’s start, with stroke rates climbing for the following two days.
Medical professionals already recognize that heart attacks, particularly severe cases, happen more frequently on Mondays and during morning hours when blood clotting increases.
Scientists haven’t determined exactly why the time change amplifies the Monday pattern, but the sudden disruption to circadian rhythms may worsen risk factors like elevated blood pressure in vulnerable individuals.
Sleep specialists recommend getting outside for morning sunlight during daylight saving time’s first week to help reset your internal clock. Adjusting daily activities like meal times and exercise schedules earlier can also signal your body to begin adapting.
Avoiding afternoon naps and caffeine, along with limiting evening screen time from phones and electronic devices, makes the transition to an earlier bedtime less difficult.
Annual discussions about eliminating time changes continue. President Donald Trump has pledged to end daylight saving time during his second term. Congressional legislation called the Sunshine Protection Act, which would make daylight saving time permanent, has repeatedly failed to advance despite bipartisan support.
Medical organizations favor a different approach. Both the American Medical Association and American Academy of Sleep Medicine support ending time changes but recommend adopting standard time year-round, arguing it better matches natural sunlight patterns and human biological needs for consistent sleep.
