The jarring sound of the clock has a harmful effect on heart health. The body's natural sleep-wake cycle is designed to prepare us for waking up and falling asleep gradually.
Waking up suddenly by the ringing of the alarm clock disrupts this natural process, causing a stress response in the body. This response, known as the "fight or flight" response, releases stress hormones such as cortisol and adrenaline, leading to an immediate increase in blood pressure. Persistent high blood pressure can lead to hardening and narrowing of the arteries, increasing risk of heart attack and stroke.