Muscle twitching while dreaming: Even healthy sleepers move more than expected
The fact that babies twitch in their sleep is nothing new, especially for parents. But adults also move during the night's sleep - and significantly more than previously thought. Researchers have now found that out. Muscle twitches during dreaming can be harbingers of neurodegenerative diseases.
Muscles twitch every six minutes during sleep
A study by scientists from the Medical University of Innsbruck has shown that even healthy people move more in their sleep than expected. According to the research group, which was supported by the Austrian Science Fund FWF, ten smaller movements per hour (i.e. on average every six minutes) are normal. However, muscle twitching during dreaming can also be a harbinger of neurodegenerative diseases, according to an article by "scilog", the magazine of the FWF.
Data was out of date until recently
For a long time, according to the researchers, it was not precisely defined how much movement there is in healthy sleep.
As Birgit Högl, head of the sleep laboratory at the University Clinic for Neurology at the Medical University of Innsbruck, explains, until recently the data for this was largely out of date.
"What we know about 'normal' movements while sleeping is still partly from the time when the sleeping person was observed through a window and handwritten minutes were made," explains Högl in the online magazine "scilog".
"Only visible and strong movements such as turning, jerking or violent swinging were recorded," said the expert.
"To diagnose a sleep disorder, brain flow curves, eye movements, muscle tension in the chin, arms and legs, various breathing parameters, ECG, sound and infrared video are recorded simultaneously in the laboratory."
In the project "Motor activity during sleep in health and illness", norm values for physiological sleep have now been collected.
Hundreds of men and women with healthy sleep were examined
Because many sleep disorders manifest themselves in unusually agitated sleep, the normal level of motor activity was the focus of this basic clinical project, which was supported by the FWF.
A total of 100 “healthy sleepers” between the ages of 19 and 77 were examined in the sleep laboratory.
The test subjects previously had clinically relevant sleep disorders such as difficulty falling asleep and staying asleep, restless legs syndrome, sleepwalking, acting out dreams, narcolepsy or other diseases with an excessive tendency to fall asleep during the day, disturbances in the sleep-wake rhythm or signs of breathing disorders in the Sleep has been excluded.
More muscle twitches in men
As it says in the “scilog” contribution, the muscles in healthy people are usefully paralyzed during the dream phase (REM sleep), since otherwise they would put themselves and others in danger if they act out their dreams.
According to the information, the research team has learned a lot from the precise measurements of what falls into the "normal" category.
"Even super-healthy sleepers move more at night than we thought", Birgit Högl told "scilog".
The scientists measured several muscle twitches per hour in healthy people in REM sleep (dreaming) and in non-REM sleep - more so for men than for women.
The clinical importance of small, irregular muscle twitches, which can be seen in the video and the muscle derivatives, is still unclear. They may just be related to your daily constitution.
Harbinger of neurodegenerative diseases
Conversely, muscle movements during the dream phase are heralds of neurodegenerative diseases such as Parkinson's.
On average, this sleep disorder occurs more than ten years before other physical symptoms.
According to the "scilog", recent studies indicate that REM sleep disorder occurs in up to six percent of people over 50 years of age. (ad)