A study carried out in the facilities of the Sleep Research Center of the University of Surrey (United Kingdom) has found that night shifts affect the intellectual performance and mood of women more negatively than that of men.
The researchers put 16 men and 18 women on 28-hour shifts without the natural cycles of light and dark, throwing off their circadian cycle, the biological clock that controls our waking and sleeping periods. The effect was similar to that of jet lag after a long plane trip.
During their waking periods, the subjects studied underwent several tests every three hours: tests of intellectual performance, memory and attention, tests of control of motor functions, questionnaires to measure their mood and their level of drowsiness … When they slept, their brain activity was measured by electroencephalography (EEG).
The results revealed two things: 1) both men and women reported feeling more affected than the objective tests of their performance showed; and 2) the circadian cycle maladjustment influenced them more: their cognitive capacity worsened more than theirs in the early hours of the morning, that is, at the end of the night shift.
Dr. Nayantara Santhi, co-author of the study, says that “we have shown for the first time that altering biological rhythms affects men and women differently in terms of cognitive ability and mood. This suggests that they could suffer more with night shifts. “
