What Are Hypnic Jerks?
Hypnic jerks, also known as sleep starts, are sudden, involuntary muscle twitches that occur as you transition from wakefulness to sleep. They often feel like you’re falling, followed by a startling jolt that wakes you up. This experience is common, with about 60-70% of people experiencing it at some point. Though unsettling, hypnic jerks are harmless and are more likely to happen when you’re sleep-deprived or exhausted.

Stages of Sleep
To understand hypnic jerks, it’s helpful to know the stages of sleep. Stage one is a light sleep where your body begins to relax, and your brain activity slows down. In stage two, this relaxation deepens, and your body temperature drops. Stage three is a deep sleep, crucial for feeling refreshed, while REM sleep occurs later, during which most dreaming happens. We cycle through these stages multiple times a night.

Why Hypnic Jerks Happen
Hypnic jerks typically occur during the transition from wakefulness to stage one sleep. When you’re sleep-deprived, your body may skip straight from stage one to REM sleep, causing these jerks. According to experts like Rafael Pelayo from Stanford Sleep Medicine Center, a hypnic jerk is your body’s way of signaling that you’re overtired and need rest.

How to Manage Hypnic Jerks
While hypnic jerks are not dangerous, they can disrupt sleep or be embarrassing in situations like meetings or lectures. To prevent them, focus on getting 7-9 hours of sleep each night. If you experience a hypnic jerk in a public setting, try making eye contact with someone or drinking coffee to stay alert. Most importantly, remember that these jerks are normal and a sign your body needs more rest.