The physical and emotional toll of menstruating is real and widespread for many women, but new research challenges the assumption that women perform worse when on their periods.
Just the opposite, it has found women are quicker at reacting and make fewer mistakes while menstruating.
However, the study by University College London and the Institute of Sport, Exercise and Health (ISEH), found between ovulation and menstruation, a period known as the luteal phase, women showed slower reaction times and poorer timing anticipation.
There were also more errors noticed around ovulation.
The research is surprising as women tend to report feeling worse on their periods, including lower mood and suffering physical symptoms.
Writing in the journal Neuropsychologia, the researchers said “a significant proportion of females felt that their symptoms were negatively affecting their cognitive performance during menstruation on testing day, which was incongruent with their actual performance”.
The study saw 241 men and women take online tests and having their moods and symptoms recorded.
They were tested twice, 14 days apart, for reaction times, attention and ability to relate to visual information as well as anticipation of when something might happen, as the tests were designed to mimic mental processes that are typical in team sports.
There was no difference between men and women’s reactions and accuracy.
But the results for females specifically “challenge what women, and perhaps society more generally, assume about their abilities at this particular time of the month”, Dr Flaminia Ronca, first author of the study, said.
In one test, participants were shown smiling or winking faces and asked to press the space bar only when they saw a smiley face. This tested inhibition, attention, reaction time, and accuracy.
In another, people were asked to identify mirror images in a 3D rotation task, while a further test asked them to click when two moving balls collided on screen.
The results showed that, for women on their periods, timing was on average 10 milliseconds (12%) more accurate in the moving balls task, and they pressed the space bar at the wrong time 25% less in the inhibition task.
In contrast, women’s reaction times were slower during the luteal phase of their cycle – an average of 10-20 milliseconds slower compared with being in any other phase.
They did not make more errors in this phase, however.
Dr Ronca said: “I hope that this will provide the basis for positive conversations between coaches and athletes about perceptions and performance: how we feel doesn’t always reflect how we perform.”
She stressed the study did not measure IQ or intelligence, so it therefore could not be suggested that women were more or less intelligent at any given phase of their cycle.
