Men, Women Display Symptoms Related to Sleep, Fatigue Differently, Study Finds

Both men and women present statistically significant associations between sleep-related movement disorders (SRMD) severity and physical fatigue, while men may have more impairment on polysomnography (PSG) and lower symptom levels, according to a recent study published by Nature and Science of Sleep.

However, women had significantly higher levels of sleep-associated complaints across all measures.

Sleepiness is generally defined “as a signal for the spontaneous onset of sleep and therefore refers to sleep propensity,” the authors wrote. Fatigue is usually thought of as a condition in which sustaining physical or cognitive tasks gets increasingly difficult.

The study involved a 1-year period of systematic clinical evaluation using structured symptom scales. A total of 796 patients (420 men and 376 women) attending an academic sleep center for PSG were evaluated using the Brugmann Fatigue Scale (BFS) as well as other scales.

Sleep disorders such as Sleep-Related Breathing (SRBD), Movement (SRMD) and Insomnia Disorders, (ID) were categorized and 4 groups were defined:

• SRBD with a Respiratory Disturbance Index (RDI) larger or equal to 15 and a Periodic Limbic Movement during Sleep index (PLMSI) lower or equal to 15
• SRMD with a clinical diagnosis of restless legs (RLS) or PLMSI larger than 15 and an RDI lower than 15
• ID with a clinical diagnosis of insomnia
• The remaining groups were RDI lower than 15 and a PLMSI lower or equal to 15 and unspecified sleep disorder (USD) being the remainders

All patients completed questionnaires about lifestyle and drinking habits. Naps were not permitted before the PSG or during hospitalization

PSG recordings included at least 3 electroencephalograms, 2 electrooculogram, submental and bilateral anterior tibial electromyograms. Oral and nasal airflow were recorded by an oro-nasal cannula, respiratory effort was measured by thoracic and abdominal belts, and capillary oxygen saturation was monitored by photosensitive finger-oxymetry

“Fatigue related to physical rest propensity, in particular, has been shown to be higher in Sleep-Related Movement Disorder (SRMD) compared to Sleep-Related Breathing Disorders (SRBD),” the authors wrote. “Statistically significant correlations between perceived sleep quality and/or daytime fatigue (but not sleepiness) and polysomnographic variables such as the Periodic Limb Movements during Sleep Index (PLMSI) have also been mentioned.”

Other research has indicated that differences in subjective sleepiness and fatigue may be related to biological sex, but why that is so is unclear.

In this study, men demonstrated higher levels of respiratory events and more periodic limb movements than women of a similar age, body mass index, total sleep time, and sleep efficiency.

Furthermore, the results suggested that associations between common markers of disease severity for SRBD or SRMD and sleep or rest propensity only demonstrated correlation between periodic limb movements and rest propensity, which was similar for both sexes.

“Sex comparison of daytime symptoms show a totally opposite pattern. Women systematically display significantly higher levels on all clinical scales. However, the clinical relevance of the latter emerges essentially for fatigue and rest propensity,” concluded the authors. “In addition, neither sleep nor mental rest propensity did show significant correlation associations to the severity of SRBD (RDI) or SRMD (PLMSI). Only physical rest propensity was significantly correlated to one marker (PLMSI) of disease (SRMD). This association was similarly strong in both men and women.”

The researchers concluded that these results act as evidence for differences in symptom-expression based on sex and diagnosis as well as suggest that movement disorders may be related to fatigue rather than sleepiness.

Reference

Van Eycken S, Neu D, Newell J, Kornreich C, Mairesse O. Sex-related differences in sleep-related PSG parameters and daytime complaints in a clinical population. Nat Sci Sleep. 2020;12:161-171. doi: 10.2147/NSS.S235642.