It’s common to experience body shakes or tremors when trying to fall asleep at night. Known as hypnic jerks or sleep starts, these involuntary muscle contractions can occur in healthy individuals. While annoying, sleep starts are not usually cause for concern. Understanding what causes them and some tips to reduce their occurrence can help you get better rest at night.
What Causes the Body to Shake Before Falling Asleep?
Your body undergoes several changes as you fall asleep. Brain wave activity slows down as you transition from wakefulness to light sleep. Muscle activity starts decreasing and you become less responsive to external stimuli. As sleep deepens, your breathing, heart rate, and body temperature drop.
Hypnic jerks are sudden, brief involuntary muscle contractions that often happen as someone is drifting off to sleep. The muscle spasms associated with hypnic jerks are most commonly seen in the legs, arms, or the whole body. These twitches can cause sensations of falling or jumping just as sleep starts.
Doctors are still researching the exact mechanisms behind hypnic jerks, but they often occur during the transition from wakefulness to sleep due to the following factors:
The Release of Hypnic Jerks
– Natural Muscle Relaxation – As the body begins to relax during the progression to sleep, hypnic jerks bring on contractions to compensate for this relaxation.
– Overactive Neural Activity – Electrical impulses from the brain can overstimulate groups of skeletal muscles as they start to relax. This causes them to contract involuntarily.
– Sudden Changes in Breathing – Respiration slows as you fall asleep. Irregularities in breathing patterns can sometimes precede a hypnic jerk.
– Anxiety and Stress – Anxiety or caffeine close to bedtime can heighten physical tension as you try to fall asleep, contributing to hypnic jerks.
– Exhaustion – Fatigue disrupts the body’s normal mechanisms for muscle hypotonia that accompany sleep onset. Jerks may occur as a result.
Other Contributing Factors
Other potential causes or contributing factors to nighttime body tremors and spasms can include:
– Using alcohol, nicotine, or recreational drugs close to bedtime
– Sleep deprivation
– Irregular sleep cycles and habits like shift work
– Excessive physical activity or strain before bed
– Dehydration or electrolyte imbalances
– Genetics – a family history of nighttime involuntary muscle contractions
– Certain neurological or movement disorders like Parkinson’s disease, multiple sclerosis, or restless leg syndrome
Are Hypnic Jerks Harmful?
For most people, hypnic jerks are not harmful or indicative of an underlying medical condition. However, they can contribute to a poor night’s sleep by:
– Causing difficulty falling asleep – It may take longer to drift off if you’re experiencing repeated muscle contractions.
– Interrupting sleep – The sensations or movements triggered by hypnic jerks can pull you out of deep sleep. This leaves you feeling unrested the next day.
– Triggering anxiety – Some people may begin to dread the falling sensation a sleep start causes, provoking anxiety around falling asleep.
– Disturbing sleep partners – Spasms from hypnic jerks can sometimes disturb a bed partner.
If hypnic jerks are severe, frequent, and disrupt your regular sleep schedule, it’s a good idea to bring it up with your doctor. They can help identify if an underlying condition is contributing to your nighttime muscle spasms and recommend solutions to help improve your sleep.
Tips to Reduce Hypnic Jerks at Night
While there is no foolproof way to avoid hypnic jerks completely, certain remedies may help reduce their frequency and intensity. Try the following methods to minimize involuntary muscle contractions at bedtime:
Sleep Hygiene Practices
Following good sleep hygiene can promote more restful sleep and make you less prone to hypnic jerks:
– Stick to a consistent sleep schedule, even on weekends
– Avoid naps late in the day
– Limit stimulating activities, food, alcohol, and screen time before bed
– Make sure your bedroom is cool, dark, and quiet
– Go through a relaxing pre-bedtime routine like reading
Reduce Anxiety
Since anxiety can contribute to hypnic jerks, relaxation techniques can help:
– Take a warm bath before bed to reduce tension
– Practice deep breathing, meditation, or light yoga to unwind
– Listen to soothing music or nature sounds
– Get a massage to relieve muscle tension
Stay Hydrated
Dehydration may worsen muscle contractions at night. Be sure to drink enough water during the day. Limit fluids 1-2 hours before bed to prevent midnight bathroom trips.
Check Medications
Ask your doctor if any medicines you take near bedtime could impact sleep or cause hypnic jerks as a side effect. Adjusting dosage or timing may help.
Mattress Check
Ensure your mattress, pillows, and bedding provide comfortable, supportive rest for your body. Upgrade mattresses older than 10 years.
Nighttime Stretches
Doing gentle stretches before bed can relax tense muscles. Try calf and hamstring stretches in bed to release lower body tension.
Massage
Massage your neck, shoulders, back, and legs with soothing essential oils to relax muscles before sleep. This may reduce spams and tremors.
Stay Active
Regular exercise during the day helps regulate sleep cycles. But avoid overexertion close to bedtime.
When to See a Doctor
In rare cases, hypnic jerks could be linked to an underlying neurological or sleep disorder. Make an appointment with your doctor if you experience:
– Frequent or severe jerks that routinely disrupt sleep
– Other unusual movements or behaviors during sleep
– Jerks combined with significant daytime fatigue, muscle weakness, or difficulty concentrating
– Jerks that persist despite good sleep hygiene practices
Diagnostic sleep studies or nerve conduction tests can help identify any underlying conditions contributing to the jerks. Treatment will focus on managing the disorder to reduce symptoms.
The Takeaway
Hypnic jerks are common, harmless muscle spasms that many people experience when transitioning from wake to sleep. While annoying, they are not usually a cause for concern and have no lingering effects once you fall asleep. Practicing good sleep hygiene, relaxation methods, and healthy habits during the day can help reduce jerks at night. For severe or persistent jerks that routinely impair your sleep, consult your doctor to check for underlying causes. With some simple lifestyle adjustments, you can minimize these involuntary contractions and get better rest.
Frequently Asked Questions
What is the medical term for body shakes when falling asleep?
The medical term is hypnic jerk or hypnagogic jerk. These involuntary contractions as you transition from wakefulness to sleep are also called sleep starts or night starts.
Why do I jerk awake when falling asleep sometimes?
This is caused by a hypnic or hypnagogic jerk. It is a sudden muscle spasm that occurs as your body begins to relax during the progression to sleep. This involuntary contraction gives the sensation of falling or jumping.
Is jerking before falling asleep normal?
Yes, hypnic jerks are very common and occur in most people without any underlying medical conditions. Up to 70% of individuals experience these harmless sleep starts as they fall asleep.
What does it mean if you jump in your sleep?
Jumping or jolting as you transition from wake to sleep is generally caused by hypnic jerks and is not cause for concern. However, if you are physically moving around or jerking excessively during sleep, it could be a sign of sleep disorder like restless leg syndrome.
Why do I shake so much before I fall asleep?
Shaking or trembling before sleep is generally caused by hypnic jerks, which are involuntary muscle contractions that occur as your body relaxes during the progression to sleep. Anxiety, caffeine, sleep deprivation, or genetics can contribute to more frequent or intense shaking.