Daylight Saving Time Could Trigger Heart Attacks—Here's Why Your Sleep Matters

When you "spring forward" for daylight saving time, your body's internal clock gets disrupted in ways that can seriously affect your heart health. Research shows a marked increase in heart attacks and strokes in the days following the spring time change each year, with one study finding a 24% spike in heart attacks on the Monday after the switch. The culprit isn't just losing an hour of sleep—it's the disruption to your circadian rhythm, your body's natural 24-hour cycle that regulates everything from heart function to blood pressure.

Why Does Daylight Saving Time Increase Heart Attack Risk?

The American Heart Association has identified circadian rhythm disruption as a key factor in cardiovascular health problems. When your internal clock gets thrown off, it can increase your risk of heart disease, obesity, type 2 diabetes, and high blood pressure. Research from Finland found that the overall rate of ischemic stroke (a type caused by blood clots) was 8% higher during the first two days after a daylight saving time transition. Even more concerning, studies show that more serious heart attacks occur on Mondays than any other day of the week, making the Monday after the time change particularly risky.

"We don't really know exactly why there is an increase in heart attacks and strokes during the change to daylight saving time. It's likely connected with the disruption to the body's internal clock, or its circadian rhythm," said Dr. Karen Wagner, a cardiologist at MaineHealth Cardiology in Scarborough. "It's important to be aware of this increased risk, especially if you already have heart disease or other risk factors."

How Does Poor Sleep Quality Damage Your Heart?

The connection between sleep and heart health goes deeper than just the time change. More than one in three adults don't get the recommended amount of sleep for heart health, and the consequences are significant. Recent research has uncovered several ways that sleep problems directly harm your cardiovascular system. A study published in the Journal of the American Heart Association found that adults who stay up late and are active at night were more likely to have poor cardiovascular health scores than people with more typical sleep-wake timing. Additionally, a study presented at the American Heart Association's Scientific Session 2025 found that long-term use of melatonin supplements, often taken to address insomnia, was associated with a higher risk of heart failure diagnosis, heart failure hospitalization, and death from any cause among adults with chronic insomnia.

Sleep problems also affect specific populations differently. Research published in the journal Hypertension found that irregular sleep patterns contributed to elevated blood pressure in adolescents who had excess belly fat. For women, the stakes are particularly high: a study in the Journal of the American Heart Association found that about one in four women may develop atrial fibrillation (irregular heart rhythms) after menopause, with stressful life events and poor sleep being leading contributing factors.

How to Prepare Your Body for Daylight Saving Time

• Get Natural Light Exposure Now: Start immediately to get outside and absorb as much natural light as possible each day. This helps adjust your body's internal clock before the time change arrives, making the transition less jarring to your circadian rhythm.
• Begin Winding Down Earlier: Start going to bed a little earlier in the evenings ahead of the time change. While you can never fully make up lost sleep, going into the transition well-rested gives your body a better foundation to handle the disruption.
• Avoid Extra Caffeine: Don't compensate for grogginess with extra coffee or energy drinks. Too much caffeine is not heart-healthy and can interfere with your sleep quality even more.

Daily Sleep Habits That Protect Your Heart

Beyond preparing for daylight saving time, the American Heart Association recommends building consistent sleep habits year-round. These practices support your circadian rhythm and overall cardiovascular health:

• Skip the Snooze Button: Sleeping past your alarm makes you groggier in the morning. Try placing your alarm clock across the room so you must physically get out of bed to turn it off, which helps you wake up more alert.
• Prioritize Morning Sunlight: Maximize exposure to natural light during the day to regulate your body's internal clock and prepare for restful sleep. Going for a walk when you wake up promotes both physical activity and natural sunlight exposure.
• Eat a Heart-Healthy Diet: Enjoy plenty of fiber-rich vegetables, fruits, legumes, and whole grains while balancing your calories throughout the day. Consuming more calories late at night can make sleep less peaceful.
• Watch Your Beverages: Limit sugary, caffeinated, and alcoholic drinks, as they can lead to more disruptions during the night and interfere with sleep quality.
• Limit Afternoon Naps: Avoid long daytime naps because they can disrupt your sleep patterns and make it harder to achieve restful sleep at night. Instead, focus on maintaining consistent sleep schedules.
• Reduce Evening Screen Time: The blue light from electronic devices can interfere with your circadian rhythm and melatonin production. Aim to disconnect from screens at least one hour before bedtime to reduce blue light exposure and promote better sleep quality.
• Create a Relaxing Bedtime Routine: Engage in calming activities before bed, such as reading a book, journaling, taking a warm bath, or practicing relaxation exercises like deep breathing or meditation to ease into restful sleep.

"Making small changes in your daily habits can make a big difference in your sleep quality and overall health," Dr. Wagner explained. "Instead of turning on the TV to help you fall asleep, try reading a book or journaling about your day. Putting your phone in another room can also prevent the temptation to scroll in bed."

How Much Sleep Does Your Heart Actually Need?

The American Heart Association has added sleep to its "Life's Essential 8," a framework of four health factors and four health behaviors needed for good cardiovascular health. The recommended sleep amounts vary by age:

• Adults: 7 to 9 hours daily
• Teenagers (ages 13-18): 8 to 10 hours daily
• Children (ages 6-12): 9 to 12 hours daily
• Young Children (ages 5 and younger): 10 to 16 hours daily

Beyond protecting your heart, adequate sleep prevents depression, cognitive decline, and obesity. The key is consistency—maintaining a healthy sleeping pattern all year long, not just around daylight saving time, is what truly protects your cardiovascular health.