Dr Balbir Singh - Head of Cardiology, Max Saket Hospital, New Delhi (India) - said that many people feel healthy but have heart attacks while sleeping. What seems sudden but in fact it is the culmination of potential risk factors that the patient has not felt or been checked.
There are several reasons why heart attacks occur during sleep:
Irregular heartbeat
According to Dr. Balbir Singh, this happens when the electrical impulses in the heart are out of rhythm and affect the synchronization of the heart muscle. The contractions can be too fast or too slow, affecting the heart's pumping mechanism.
Brugada syndrome is a genetic disorder that can cause dangerous irregular heart rhythms. The lower chambers of the heart (ventricles) beat rapidly and irregularly, preventing blood from circulating normally.
The problem with arrhythmia is that the irregular heartbeat or arrhythmia becomes worse when the body suddenly switches to a state of wakefulness while in sleep.
This process also causes the stress hormone cortisol to surge in the body, preparing the body to move into the activity phase. Rapid fluctuations in heart rate can cause the heart to stop beating, causing sudden cardiac arrest.
Normally, the body is in a resting state in the middle of the night, explains Dr. Balbir Singh. The parasympathetic nervous system (responsible for stimulating rest and digestion or eating and reproduction) releases acetylcholine, a hormone that slows the heart rate. Underlying conditions such as diabetes or electrolyte imbalances due to dehydration and low potassium and magnesium levels can affect the parasympathetic system's activity, causing arrhythmias.
Heart attacks caused by blockages
After midnight, levels of blood-thinning proteins increase, causing platelets to clot more quickly, says Dr. Balbir Singh. If you have risk factors like cholesterol, obesity, high blood pressure, and diabetes, anything that causes inflammation in the body, clotting can be the final straw and block blood flow to the heart.
Sleep Apnea
In this condition, your muscles, especially those in your neck, relax during sleep. As a result, your airways collapse and contract, slowing down the oxygen supply to your lungs.
If you stop breathing intermittently for 10 seconds or longer while sleeping, this puts stress on your heart.
Additionally, your blood pressure typically drops at night, which can increase and trigger a surge of stress hormones like cortisol and adrenaline.
“This puts extra stress on your heart to normalize your blood pressure. Researchers have found that sleep apnea increases inflammation, changes blood vessel walls, and causes irregular heart rhythms, all of which can trigger a heart attack,” says Balbir Singh, MD.
