Women do not suffer any detriment to their brain function while on their period, new research has suggested.
Experts at University College London said that while many women report feeling worse while menstruating, their study found “no evidence” to suggest these mood symptoms impacted participants’ cognition.
The paper, published on Friday in the journal Sports Medicine – Open, said that while the study did identify times in the menstrual cycle when women’s cognitive function was better or worse, neither of these were during the menstruation phase while a woman is on her period.
Researchers tracked the menstrual cycles of 54 women aged between 18 and 40 across the four key phases. Participants were asked to complete a 10-part questionnaire to assess their mood and take two cognitive tests on the first day of menstruation, two days after the end of menstruation (late follicular phase), the first day ovulation was detected, and between ovulation and menstruation (mid-luteal phase).
Analysis showed that while women reported symptoms such as headaches, pain, brain fog, and grumpiness during their menstrual phase, these symptoms did not impact their reaction times and attention levels.
Instead, their findings showed participants had slower reaction times during the mid-luteal phase, and made more errors during the late follicular phase – despite these not being times when women typically assume performance to be affected.
Brain function was found to peak during ovulation – when an egg is released – with participants demonstrating reaction times 30 milliseconds faster than during the mid-luteal phase.
Speaking to The Independent, lead author Dr Flaminia Ronca said she hopes the study generates “positive” discussions around women’s cognitive performance during menstruation.
“Women say they feel that they might be at a disadvantage on their periods because some some women experience symptoms like brain fog and headaches,” she explained. “If we just think about the broad question of does cognitive function change the menstrual cycle, the answer is yes but not in the way that women perceive, which is quite positive.
“We need to start separating how we feel from how we perform. You might be in pain and you might be in a bad mood. That does not determine your performance. You can still perform at at your very best.”
Dr Ronca stressed that while the academics were tracking brain function, this was not the same as intelligence. “We’re not measuring IQ here. They’re not becoming dumber or smarter,” she said.
She added that while the millisecond differences in reaction time measured by scientists were likely to be “inconsequential” in everyday life, the findings were particularly relevant to women’s sport, where slightly quicker reaction times of around 20 milliseconds may make the difference between sustaining or avoiding an injury like a concussion.
Previous research on elite athletes has suggested injuries are more common at certain points during the menstrual cycle, and Dr Ronca said that these changes in cognition might partially explain this.
“Where it does matter is in contact sports where things are moving very quickly and a concussion typically happens in the space of nine to 18 milliseconds,” she explained.
Researchers also separated participants into groups depending on how active they are. Scientists found that compared to active participants, inactive participants had reaction times on average around 70 milliseconds slower and made around three times as many impulsive errors, regardless of cycle phase.
“70 milliseconds is enough time for the brain to register a stimulus and initiate a voluntary reaction, and is therefore far more meaningful for everyday life,” Dr Ronca said.
“This shows the importance of incorporating some form of recreational physical activity into our lives. It doesn’t have to be that intense or competitive to make a difference – and crucially, it’s something that we can control.”
