Large Muscle Group Movements During Sleep Evolve as People Age

Large muscle group movements during sleep are more frequent among older adults than younger people, but become shorter in duration over time, according to study findings published recently in the Journal of Sleep Research.

Recent research has demonstrated that large muscle group movements may have clinical utility among individuals with sleep disorders, as they are linked to changes in sleep activity. Although large muscle group movements have been assessed among patients with restless legs syndrome, comprehensive data on these movements across the lifespan, particularly among healthy people, is sparse.

To address this knowledge gap, investigators conducted a cross-sectional study to evaluate age-related changes in large muscle group movements during sleep and their relationship with sleep architecture. Study participants were healthy adults who underwent polysomnography during overnight sleep studies at a sleep laboratory. The investigators used the polysomnographic recordings to record sleep data and to visually detect and score these movements.

A total of 141 healthy participants, all Caucasians from Italy, were included in the study. The participants were categorized into 5 different age brackets: school-aged children aged 5 to 12 years (n=43), adolescents aged 13 to 17 years (n=31), young adults aged 18 to 35 years (n=27), adults aged 36 to 60 years (n=16), and older adults over 60 years of age (n=24). Individuals with physical, neurological, or psychiatric disorders or history of sleep problems were excluded.

Movements were classified as large muscle group movements not associated with arousal or awakening, associated with an arousal (LMMA), or associated with an awakening (LMMW). Additionally, the investigators counted these movements separately during rapid eye movement (REM) and non-rapid eye movement (NREM) sleep.

The investigators found that each category demonstrated significant changes with increasing age. Older participants had significantly higher indices for large muscle group movements (F=3.547; P =.009), LMMA (F=3.001; P =.021), and LMMW (F=23.768; P <.001). However, there was a significant inverse relationship between participant age and duration of large muscle group movements (F=23.842; P <.001), as younger participants had a longer duration of nighttime movements.

When stratified by REM vs NREM sleep, the investigators found that LMMA and LMMW indices were significantly higher during NREM sleep among school-aged children (both P <.05), while adults exhibited higher LMMA and total large muscle group leg movement indices during REM sleep (both P <.05). These changes may reflect age-related sleep fragmentation and instability.

No significant sex differences in these movements were found across age groups, but the investigators noted that future research with larger cohorts is needed to clarify the role of sex.

This study is the first to provide a comprehensive cross-sectional analysis of large muscle group movements during sleep across the lifespan. These findings suggest that sleep-related motor activities evolve with age and are closely linked to changes in sleep architecture.

 “[O]ur finding that [large muscle group movements] increase with age, even in healthy individuals, underscores the importance of considering age-related normative values when diagnosing sleep disorders,” the investigators concluded. “In clinical settings, distinguishing between age-related increases in [large muscle group movements] and pathological movements associated with sleep disorders is critical for accurate diagnosis and treatment.”

Study limitations include the small sample size and the inability to evaluate longitudinal changes in leg movements over the lifespan, given the cross-sectional design.

This article originally appeared on Sleep Wake Advisor