According to the research, women experienced a more notable decline in cognitive function following night shifts compared to men. The impact of working overnight had a significantly stronger effect on the brain performance of women.
According to a study published in the Proceedings of the National Academy of Sciences, conducted by the Surrey Sleep Research Centre (SSRC) at the University of Surrey, UK, it has been revealed for the first time that disrupted sleep-wake cycles impact men and women differently, leading to noticeable variations in cognitive function and alterations in mood.
The study’s lead author, Dr. Nayantara Santhi, a research fellow at the SSRC, suggests that women may be more affected by night shift work than men based on the study’s results. This could have significant implications for women working in professions such as nursing and law enforcement that require night shift work.
The circadian rhythm, also known as the body clock, is responsible for regulating our daily cycles as we transition between wakefulness and sleep. A “master clock” in the brain coordinates various bodily processes, including hormone production, metabolism, and blood pressure, to ensure they are synchronized.
Recent evidence suggests that certain circadian features, such as the frequency and amplitude of melatonin production, may differ between men and women. However, researchers are now investigating whether these differences extend to mental function, which would be a novel finding.
Circadian rhythm changes affect brain differently in men and women
In a research study conducted at the SSRC, 16 male and 18 female volunteers were subjected to a 28-hour day cycle in a monitored sleep laboratory. This altered their natural circadian rhythm from the standard 24-hour cycle to a 28-hour cycle, leading to disrupted sleep patterns similar to those experienced during shift work or due to jet lag.
At regular intervals during the day, the participants underwent objective tests to evaluate their performance in areas such as attention, motor control, and working memory. Additionally, they provided subjective feedback on their level of sleepiness, mood, and effort.
The study involved monitoring the electrical activity in the brains of participants through continuous readings (EEGs) while they slept. The findings revealed that the subjective measures based on self-assessments were more responsive to the influence of time awake and circadian rhythm compared to the objective measures of performance for both men and women.
However, the study’s most significant discovery was that women’s performance was more adversely affected than men’s during the early morning period, which typically coincides with the end of a night shift for shift workers. This finding highlights that women may experience more significant challenges in adapting to night shift work than men.
Senior author Derk-Jan Dijk, professor of sleep and physiology at the University of Surrey, concludes:
“These results show that in both men and women circadian rhythmicity affects brain function and that these effects differ between the sexes in a quantitative manner for some measures of brain function.”
The author emphasizes that the study underscores the significance of incorporating both male and female participants in such research endeavors, as well as utilizing a variety of objective and subjective indicators to gauge brain functioning.
Sources Of Story ;
- Sex differences in the circadian regulation of sleep and waking cognition in humans, Nayantara Santhi et al., Proceedings of the National Academy of Sciences, doi:10.1073/pnas.1521637113. https://www.pnas.org/doi/abs/10.1073/pnas.1521637113
- Additional source: National Institute of General Medical Sciences https://www.nigms.nih.gov/education/fact-sheets/Pages/circadian-rhythms.aspx