Exercise increases women’s brain capacity more than the time of ovulation

Summary: While women’s reaction times and accuracy peak during ovulation, physical activity level plays a much larger role in cognitive performance. Inactive participants had reaction times about 70 milliseconds slower and made three times more impulsive errors compared to active women, regardless of menstrual phase.

The study suggests that fitness has a stronger influence on brain function than hormonal fluctuations, with significant effects for both sports performance and daily coordination. These findings challenge assumptions about menstruation-related performance declines and emphasize the brain-boosting benefits of regular exercise.

Key facts:

Peak performance at ovulation: Women performed faster and more accurately during ovulation, reacting about 30 milliseconds faster than later in the cycle. Exercise matters more: Physically active women reacted 70 milliseconds faster and made far fewer impulsive errors than inactive participants, regardless of cycle phase. Practical Impact: Even small gains in reaction time can prevent sports injuries and improve daily coordination, highlighting the cognitive benefits of habitual activity.

Source: UCL

Women performed better on cognitive tests during ovulation, but physical activity level had a greater influence on brain function, according to a new study by UCL researchers.

The study, published in Sports Medicine – Open, explored how different phases of the menstrual cycle and level of physical activity affected performance on a variety of cognitive tests designed to mimic mental processes used in team sports and everyday life, such as precise timing of movements, attention and reaction time.

The team found that women had the fastest reaction times and made the fewest errors on the day of ovulation, when the ovaries release an egg ready to be fertilized (and when the woman’s fertility is at its peak).

But while cognitive performance fluctuated throughout the menstrual cycle, much larger differences were seen between those who were active and those who were not. Compared to active participants, inactive participants had reaction times on average about 70 milliseconds slower and made about three times as many impulsive errors, regardless of cycle phase.

The researchers say the findings are particularly relevant to women’s sport, where slightly faster reaction times, of around 20 milliseconds, can make the difference between suffering or avoiding an injury such as a concussion.

Previous research in elite athletes has suggested that injuries are more common at certain points during the menstrual cycle, and the authors say these changes in cognition could partially explain this occurrence.

However, while a difference of 20 milliseconds is unlikely to have any consequences in everyday life, the much larger difference between the active and inactive groups is more significant, where 70 milliseconds could determine whether we regain our balance after tripping over an obstacle or not.

Dr Flaminia Ronca, lead author of the study from UCL Surgery and Interventional Sciences and the Institute of Sport, Exercise and Health, said: “This is the first time we have directly measured ovulation in this context and we found that cognitive performance was better during this phase, with participants reacting around 30 milliseconds faster compared to later in their cycle, during the mid-luteal phase before periods begin. At an elite level, this could make the difference between sustaining a serious injury in a collision or not.

“But the really interesting finding to me is that the difference between those who were active and inactive was much larger, around 70 milliseconds, which is enough time for the brain to register a stimulus and initiate a voluntary reaction and is therefore much more meaningful for everyday life.

“This shows the importance of incorporating some form of recreational physical activity into our lives. It doesn’t have to be so intense or competitive to make a difference and, more importantly, it’s something we can control.”

The research included 54 naturally menstruating women between the ages of 18 and 40 (not using hormonal contraceptives), who were categorized into four groups based on their level of athletic participation: inactive (reported not participating in any form of structured exercise), recreationally active (participating in at least two hours of structured exercise per week), competing in any sport at the club level, and elite (competing in any sport at the national or national level). international)1.

The researchers followed the participants through the four key phases of the menstrual cycle. Participants completed a 10-part questionnaire to assess their mood and completed cognitive tests2 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).

Confirming previous findings by UCL researchers, the new study showed that reaction times were slower during the mid-luteal phase, likely due to increased levels of the female sex hormone progesterone, which is known to slow down the brain. However, this did not lead to more errors, suggesting that the slower processing speeds observed during this phase do not necessarily compromise accuracy.

More errors were observed in the late follicular phase (just after the period ends). Researchers say it is not yet known why this would be the case.

Participants again reported less energy and more symptoms during menstruation, but these subjective experiences did not correlate with actual performance. 55% of participants believed that their symptoms during menstruation affected their performance, but the researchers found no evidence of this; in fact, reaction time was also faster than during the mid-luteal phase.

Evelyn Watson, study author from UCL Surgery and Interventional Sciences and the Institute of Sport, Exercise and Health, said: “It’s great to see that, while participants assumed they performed worse during menstruation, the findings do not demonstrate any detriment to cognition.

“If anything, cognitive performance peaked during ovulation. This is a positive result that we hope can help develop a new narrative about female health and performance.”

Dr. Ronca concluded: “Incorporating exercise into our daily lives doesn’t have to be difficult. Some of our previous studies have shown that 15 minutes of moderate activity is enough to improve our mood and cognitive performance, which is equivalent to taking a brisk walk around the block or cycling to the shops.”

Key questions answered:

About this research news on cognition, exercise and ovulation

Author: Matt Midgley
Source: UCL
Contact: Matt Midgley – UCL
Image: Image is credited to Neuroscience News.

Original research: Open access.
“Menstrual cycle and athletic status interact to influence symptoms, mood, and cognition in women” by Flaminia Ronca et al. Sports Medicine – Open

Abstract

Menstrual cycle and athletic status interact to influence symptoms, mood, and cognition in women

Background

There is growing interest in understanding whether and how the menstrual cycle can affect physical and cognitive performance, especially in the context of sport and physical activity. While hormonal fluctuations are often assumed to affect cognition, especially during menstruation, empirical evidence remains inconclusive. This study aimed to investigate whether cognitive performance, mood, and symptomatology vary between phases of the menstrual cycle and whether these effects are influenced by the level of athletic participation.

Results

Fifty-four women (18 to 40 years) participated, classified by level of athletic participation (i.e., inactive, active, competitive, elite). At each key menstrual phase (menstruation/early follicular, late follicular, ovulation, and mid-luteal), they completed a cognitive battery (attention, inhibition, and spatial anticipation) and reported their mood and symptoms. Faster reaction times and fewer errors were made during ovulation (p < 0.01), suggesting better overall performance.

In contrast, reaction times were slower during the luteal phase (p < 0.01), but more errors were made in the follicular phase (p = 0.01). Importantly, participants' athletic level had a stronger effect on cognitive performance than phase, with inactive participants scoring worse on the tasks than their more active counterparts, and elite participants showing more significant fluctuations in cognition between phases.

Mood and symptoms worsened during menstruation regardless of athletic level. However, although mood varied between phases, it did not correlate with cognitive performance.

Of note, participants perceived their symptoms to negatively impact their cognitive performance during menstruation, but there was no evidence of any objective impairment in cognitive performance during this phase in either reaction times or errors on any task.

Conclusion

These findings suggest the existence of slight cognitive fluctuations throughout the menstrual cycle, although with high individual variability, and which are incongruent with the symptomatology.

The contrasting results between perceived and measured performance challenge common assumptions about menstruation-related performance and highlight the importance of addressing social biases in women’s sport and health.

The stronger effects of athletic engagement on cognitive performance, rather than phase, reinforce the cognitive benefits of an active lifestyle.