Spring Forward 2026: What Losing an Hour of Sleep Does to Your Body

On March 8, 2026, most of the United States moved clocks forward for daylight saving time. That meant losing one hour of sleep overnight. For many people, it felt like a minor inconvenience. But research suggests that even a one-hour shift in sleep and light exposure can temporarily affect heart health, mood, alertness, and safety.

The overall risk for any one person remains low. Still, when millions of people shift their sleep at once, small effects can show up at the population level. Here’s what the evidence shows—and what families can do to reduce disruption.

How One Hour Affects the Body

Your body runs on an internal 24-hour clock called the circadian rhythm. It helps regulate sleep, hormone release, blood pressure, heart rate, digestion, and alertness. Light is the main signal that sets this clock.

When clocks “spring forward,” morning light comes later by the clock, and evening light stretches longer. That delays the release of melatonin, the hormone that signals your body it’s time to sleep. For many people, especially teens and night owls, it becomes harder to fall asleep earlier—even though work and school start at the same time.

According to the National Heart, Lung, and Blood Institute (NHLBI), ongoing sleep deprivation is linked to higher blood pressure, increased heart strain, insulin resistance, and inflammation. Even short-term sleep loss can temporarily raise heart rate and stress hormone levels.

The American Academy of Sleep Medicine (AASM) explains that daylight saving time creates a misalignment between the social clock (work and school schedules) and the body clock. That misalignment is most pronounced in the days right after the spring shift.

A Sleep-Deprived Nation Is More Vulnerable

The impact may be greater because many Americans are already not getting enough rest. According to the Centers for Disease Control and Prevention (CDC), about 1 in 3 U.S. adults report not getting the recommended amount of sleep on a regular basis.

If you are already short on sleep, losing another hour can deepen sleep debt and worsen alertness. For people living with chronic insomnia, obstructive sleep apnea, or long work hours, the adjustment may take several days.

What the Research Shows About Heart Risk

Several studies have examined whether heart events change around daylight saving time transitions. Most of this research is observational, meaning it looks at patterns in large groups of people rather than testing cause and effect in a controlled trial.

An early letter published in the New England Journal of Medicine reported a short-term increase in heart attacks in the days following the spring shift. More recently, a peer-reviewed study in JAMA Cardiology analyzed national cardiovascular data and found a modest increase in certain heart-related events immediately after the transition.

These increases were small in percentage terms, but measurable across large populations. Importantly, observational studies cannot prove that daylight saving time directly causes heart attacks. Other factors—such as stress, routine changes, or seasonal variation—may also play a role. Still, the consistent timing across studies suggests sleep disruption is a likely contributor.

For individuals without heart disease, the absolute risk remains low. But for people with known cardiovascular disease, uncontrolled high blood pressure, or a history of heart attack, even temporary strain may matter.

Crashes and Workplace Injuries

Researchers have also studied traffic collisions and workplace injuries during the days after the spring clock change. Several analyses have found short-term increases in motor vehicle crashes and on-the-job injuries following the transition.

Sleep loss affects reaction time, attention, and decision-making. Even one hour less sleep can reduce alertness the next day. In a country where many people commute long distances or operate heavy equipment, small reductions in attention can translate into measurable safety effects.

Again, these are population-level patterns. They do not mean every driver is at high risk. But the findings are consistent with what we know about sleep and performance.

Who May Be Most Affected

People with heart disease or stroke risk factors
Shift workers, who already have circadian disruption
Teens, whose body clocks naturally run later
Chronically sleep-deprived adults
People with sleep disorders, such as insomnia or sleep apnea

If you fall into one of these groups, it may take longer for your body clock to adjust.

The Policy Debate: Permanent Standard Time?

The American Academy of Sleep Medicine has issued a position statement recommending permanent standard time rather than permanent daylight saving time. The organization argues that standard time better aligns with human circadian biology because it provides more morning light, which helps regulate sleep–wake cycles.

Some lawmakers have proposed making daylight saving time permanent, while others support permanent standard time. The debate is ongoing at the federal level. There is not universal agreement on policy, but the AASM’s recommendation reflects concerns about chronic circadian misalignment.

How Families Can Reduce Risk After the Time Change

You cannot undo the clock change, but you can reduce its impact:

Shift gradually: Go to bed 15–20 minutes earlier for several nights before and after the transition.
Prioritize morning light: Spend time outdoors in the morning to help reset your body clock.
Keep a consistent schedule: Wake up at the same time each day, even on weekends.
Avoid late-night screens: Bright light in the evening delays melatonin.
Be cautious while driving: Especially during the first few days, allow extra travel time and avoid drowsy driving.
Manage heart risk factors: Take prescribed medications, monitor blood pressure if advised, and seek care for new chest pain or shortness of breath.

When to Seek Medical Care

Seek emergency care immediately for chest pain, sudden shortness of breath, weakness on one side of the body, slurred speech, or severe confusion. These can be signs of heart attack or stroke.

If you continue to struggle with sleep for weeks after the time change, talk with your healthcare provider. Ongoing insomnia, loud snoring with daytime sleepiness, or chronic fatigue may signal an underlying sleep disorder.

The Bottom Line

Losing one hour of sleep on March 8, 2026, may seem minor. But research suggests that even small shifts in sleep and light exposure can temporarily affect heart strain, mood, alertness, and safety—especially in a country where many adults are already sleep deprived.

The increases in heart events and crashes seen in studies are modest and based on observational data. They do not mean the clock change directly causes medical emergencies. Still, the pattern is consistent enough that sleep specialists recommend taking the transition seriously.

A small shift can have real effects—but most of the risk is manageable with good sleep habits and extra caution during the first week.

Sources

This article is for general informational purposes only and is not medical advice. Research findings can be early, limited, or subject to change as new evidence emerges. For personal guidance, diagnosis, or treatment, consult a licensed clinician. For current outbreak or public health guidance, follow your local health department, the CDC, or another relevant public health authority.