Women may feel worse during their time of the month, but their minds are sharper according to new research.
London researchers found that women reacted 12 percent faster and made 25 percent fewer errors during menstruation in psychological tests.
This was despite the women saying they expected their performance to suffer.
The study, published in the journal Neuropsychologia, found that women showed “better overall cognitive scores during menstruation, despite reporting worse mood and symptoms.”
Scientists say the findings may provide an explanation for previous research that female athletes are less likely to be injured when they are menstruating.
One study found that women reacted 12 percent faster and made 25 percent fewer errors during menstruation in psychological tests. This was despite the women saying they expected their performance to suffer.
They say estrogen (the hormone that increases during menstruation in women) may be stimulating brain function, while progesterone, the hormone that activates before menstruation, inhibits it.
The study looked at 248 participants, all between the ages of 30 and 20, including 105 women, of whom 47 were taking contraceptives, and 96 men.
The researchers set up complicated screen-based tests aimed at mimicking the mental processes typical of team sports.
They included pressing buttons only when they saw a correct signal and timing their pressing a button exactly when two balls collide.
They also had to identify mirror images of rotating shapes in three dimensions, a test that measures spatial awareness.
Menstruating women were on average 10 milliseconds (12 percent) more accurate on the ball-moving task, and pressed the space bar at the wrong time 25 percent less often on the inhibition task.
The researchers found that menstruating women had slower reaction times, of around 10 to 20 milliseconds, during the luteal phase, which begins after ovulation and lasts 12 to 14 days until the start of menstruation. They made no more mistakes during this phase.
Dr Flaminia Ronca, from UCL, first author of the study, said there were no group-level performance differences between men and women.
The only differences in performance found were fluctuations within the group of menstruating women.
He said his research suggests that women suffer injuries before they start menstruating because the hormones affect their brains and not their muscles.
She said: “What is surprising is that the participants’ performance was better when they were on their period, which challenges what women, and perhaps society as a whole, assume about their abilities at this particular time of the month.
“I hope this informs positive conversations between coaches and athletes about perceptions and performance – how we feel does not always reflect how we perform.”
The authors say that fluctuation in time, even just 10 milliseconds, could make the difference between an injury or not.
