Sleeping is not always safe: Heart attack can strike amid nighttime. Know the silent warning signs

Heart attacks are a leading cause of death worldwide, and while they are commonly linked to daytime stress, physical exertion, or emotional strain, medical evidence shows that a significant number also occur during sleep or in the early morning hours. This is because the body’s circadian rhythm influences heart rate, blood pressure, and hormone levels at night, which can increase vulnerability to cardiac events. Many people are unaware that night-time heart attacks often present subtle signs that are easily overlooked, making awareness and timely response critical to preventing severe outcomes.

According to the Mayo Clinic, a heart attack occurs when the flow of blood to the heart is severely reduced or blocked, usually due to the buildup of plaques—fatty, cholesterol-containing deposits—in the coronary arteries. If a plaque ruptures, a blood clot can form, obstructing blood flow and damaging heart muscle. During sleep, blood pressure typically drops, but certain conditions such as stress, irregular sleep patterns, or undiagnosed heart disease can still trigger cardiac events. Research published in PubMed indicates that nearly 20% of myocardial infarctions occur between midnight and 6 AM, emphasizing that night-time heart attacks may have distinct characteristics compared to those occurring during the day.

Common Night-Time Warning Signs
Even while asleep, the body may send signals indicating that something is wrong. Chest discomfort or pressure, often described as tightness, squeezing, or aching, can sometimes radiate to the arms, neck, jaw, back, or upper abdomen and may be more pronounced when lying down. Shortness of breath can appear suddenly, causing people to wake up gasping or feeling that their lungs are not receiving enough oxygen.


Unusual sweating, including cold or clammy skin and night sweats without a clear cause, may also signal cardiovascular stress. Nausea, lightheadedness, or fainting can indicate reduced blood flow to the heart or brain. A rapid, fluttering, or irregular heartbeat at rest is another warning that should not be ignored. Women, in particular, may experience atypical symptoms such as sharp or brief pain in the neck, arm, or back.

Factors That Increase Night-Time Heart Attack Risk
Certain health conditions and lifestyle habits can make night-time heart attacks more likely. High blood pressure puts additional strain on the heart, while sleep apnoea, which causes interrupted breathing during sleep, elevates cardiac risk. Diabetes can affect blood sugar and overall heart health, and obesity increases the workload on the heart even while resting.

Chronic stress may trigger hormonal changes that precipitate a cardiac event, while smoking and excessive alcohol consumption further impair cardiovascular function. Individuals with these risk factors need to be especially vigilant about recognizing night-time warning signs.


Preventive Measures
Although it is impossible to prevent every heart attack, adopting heart-healthy habits can significantly lower the risk. Maintaining a balanced diet low in saturated fats, sugar, and salt helps protect arteries from plaque buildup. Regular exercise strengthens heart function and circulation, while good sleep hygiene and addressing conditions like sleep apnoea can reduce night-time risk.

Avoiding smoking and limiting alcohol consumption are critical steps in preserving cardiovascular health. Regular monitoring of blood pressure, cholesterol, and blood sugar can help detect problems early, and managing stress through relaxation techniques such as meditation or yoga may also provide protective benefits. Prompt attention to any unusual nighttime symptoms and timely medical intervention can make a life-saving difference.