Dr Amir Khan, a familiar face on ITV's Good Morning Britain and Lorraine, has explained the science behind the sudden body jolt that wakes you up just as you're about to fall asleep. Known as a hypnic jerk, this phenomenon is experienced by around 60 to 70 per cent of people, according to The Sleep Charity.
What Is a Hypnic Jerk?
In a TikTok video, Dr Khan said: "Have you ever felt you're falling just as you nod off? That sudden jolt awake is actually called a hypnic jerk." He elaborated: "As you drift into sleep, your muscles relax, and sometimes your brain interprets that as falling. It's a misinterpretation, so it sends a quick signal to your body to catch you, and that's why you twitch awake."
Dr Khan added that some scientists believe it is an ancient survival reflex from when humans slept in trees, where a sudden twitch might have prevented falling. He reassured viewers it is "totally harmless" and more common when stressed, after caffeine late in the day, or when extremely tired.
Common Causes
The Sleep Charity notes that hypnic jerks are involuntary twitches occurring during the first stage of light sleep. They can affect the whole body or just the legs and are often accompanied by a sensation of falling, a loud noise, or a flash of light. Factors that can trigger them include caffeine, alcohol, stress, physical exercise too close to bedtime, and other sleep disorders like sleep apnoea.
The charity advises that treatment is not necessary unless hypnic jerks occur frequently with other symptoms such as physical injury, bedwetting, or confusion upon awakening. In such cases, a GP should be consulted.
Tips to Reduce Hypnic Jerks
The Sleep Foundation recommends several strategies to help reduce hypnic jerks:
- Going to bed and waking up at the same time every day
- Keeping the bedroom between 18 and 20 degrees Celsius
- Making the bedroom dark and quiet
- Avoiding electronics at least one hour before bed
- Reducing stress through yoga, meditation, reading, or taking a bath
- Exercising daily but not late in the evening
- Limiting caffeine, nicotine, and alcohol
Dr Khan concluded: "So next time it happens, don't panic. It's just your brain being quirky."
