Health & Medicine

Study: Women's Brain Suffer More Than Men During Shifted Sleep-Wake Cycle

Johnson Denise
First Posted: Apr 21, 2016 04:06 AM EDT

A study from the Surrey Sleep Research Center at the University of Surrey has discovered that constant lack of sleep or shifter's sleep-wake cycle affects both sexes. They have also found that although the condition can affect both genders differently. Medical conditions such as mood disorders, reduced brain function and Alzheimer's disease have all been found to be connected to inadequate sleep.

Although some studies show that these disorders are more common in women, they were found to be underrepresented in both circadian and sleep research, according to a new study. The study's author said that the effects have been properly documented; however sex difference specifically related to the internal clock have not.

Medical Daily reported that a person's circadian rhythm is partially responsible for regulating sleep. This biological clock helps humans match their behavior with the time of the day: they are up and ready for the day's work when the sun is out and ready to retire to bed after dark falls. These cues come from a group of nerve cells which can be found almost everywhere in the body. When it fails to work properly, the biological clock will also stop to function normally.

For the study, researchers placed 16 male and 18 female participants on 28-hour days in a controlled environment without natural light-dark cycles. The environment setup effectively messed up the sleep-wake cycle of the participants similar to when someone is having a jetlag or a shiftwork scenario.

The participants were made to perform a wide range of tests every three hours of their awake period. These tests range from self-reported assessment of sleepiness, mood, and effort and different cognitive performance which measures attention, motor control and how their memory works. According to Sleep Review Magazine, the participants' brain electric activity (EEG) was continuously monitored while they were sleeping.

The results showed that both gender's self-reported assessments were more sensitive to the effects of time awake and circadian clock than the objective measures of performance. However, researchers found that the circadian effect on performance was essentially stronger in women than in men as evidenced by women being more cognitively impaired during the early hours of the morning, which is equivalent to the end of a night shift in the real world.

Senior author Professor Derk-Jan Dijk, BSc, MSc, Ph.D., FSB, says, "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." He also added that the overall findings show the importance of including both sexes in research studies and to using various kinds of subjective and objective indicators of brain function.

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