A groundbreaking UCL study reveals that while cognitive function subtly peaks during ovulation, the benefits of an active lifestyle have a far more profound and consistent impact on reaction time and accuracy, challenging long-held beliefs about menstruation and performance.
For generations, the menstrual cycle has been a subject of speculation, often blamed for everything from mood swings to dips in physical and mental performance. Many women have been told, or simply felt, that their cognitive sharpness wanes at certain times of the month. But what if the biggest factor influencing our brainpower isn’t our hormonal cycle, but something entirely within our control? A new study from researchers at University College London (UCL) dives deep into this question, and its findings are shifting the narrative around female health, fitness, and cognition. The surprising conclusion: regular physical activity is a far more powerful brain booster than the timing of ovulation.
The study, published in Sports Medicine – Open, did confirm that hormonal fluctuations have a measurable, albeit small, effect on cognitive abilities. The research team meticulously tracked participants across four key phases of their cycle and found a clear peak in performance on the day of ovulation. During this phase, when an egg is released and fertility is at its highest, women reacted about 30 milliseconds faster and made fewer errors on cognitive tests compared to their performance later in the cycle.
Conversely, the researchers observed a slight slowdown during the mid-luteal phase (the time between ovulation and menstruation). This dip in reaction time is likely linked to increased levels of progesterone, a hormone known to have a calming, and sometimes slowing, effect on the brain. Interestingly, while reaction times were slower, accuracy wasn’t compromised, suggesting the brain compensates to maintain precision. These findings paint a picture of a subtle ebb and flow in cognitive function tied to our biology. However, this is only a small part of a much bigger story.
The most striking discovery from the UCL study was the dramatic difference between active and inactive participants. This wasn’t a subtle shift; it was a chasm. Regardless of where they were in their menstrual cycle, physically active women consistently outperformed their inactive counterparts by a significant margin.
On average, active women had reaction times that were a staggering 70 milliseconds faster than inactive women. To put that in perspective, the hormonal advantage seen during ovulation was less than half of this. Furthermore, inactive participants made around three times as many impulsive errors. As lead author Dr. Flaminia Ronca explains, this 70-millisecond difference is incredibly meaningful in the real world. It "is enough time for the brain to register a stimulus and initiate a voluntary reaction," she notes. It could be the difference between catching your balance after tripping on a curb or taking a hard fall. The message is unequivocal: fitness has a stronger, more consistent influence on brain function than hormonal fluctuations.
Perhaps one of the most fascinating aspects of the study is how it contrasts objective data with subjective feelings. A significant 55% of participants believed their cognitive performance was impaired during menstruation. They reported lower energy and more symptoms, and they felt these were holding them back. The data, however, told a different story.
The researchers found no objective evidence of cognitive decline during menstruation. In fact, reaction times during this phase were still faster than during the sluggish mid-luteal phase. This disconnect highlights a powerful societal narrative that often frames menstruation as a period of weakness or impairment. "It’s great to see that, while participants assumed that they were performing worse during menstruation, the findings don’t demonstrate any detriment to cognition," said Evelyn Watson, an author of the study. This research helps to build a new, more positive and evidence-based narrative in female health, suggesting that what we feel isn’t always what we do.
The study’s findings have important implications for two very different groups: elite athletes and everyone else. For professional athletes, where victory can be decided by fractions of a second, the 20-30 millisecond cognitive boost during ovulation could be relevant. Previous research has hinted that injury rates might be higher at certain points in the cycle, and these subtle changes in reaction time could be a contributing factor, potentially making the difference in avoiding a collision or a concussion.
For the rest of us, however, the much larger 70-millisecond advantage conferred by an active lifestyle is the real headline. This isn’t about winning a gold medal; it’s about enhancing everyday coordination, improving safety, and boosting overall brain health. The study powerfully demonstrates that we have a significant degree of control over our cognitive function. "The really interesting finding for me is that the difference between those who were active and inactive was much greater," Dr. Ronca emphasized, highlighting its relevance for daily life.
This landmark research from UCL provides a clear and empowering takeaway: if you want to sharpen your mind, focus on moving your body. While the menstrual cycle introduces minor fluctuations in cognitive performance, these are dwarfed by the profound and lasting benefits of regular physical activity. The study dismantles outdated assumptions about menstruation and performance, replacing them with a data-driven understanding that puts agency back in women’s hands.
And you don’t need to train like an elite athlete to reap the rewards. As Dr. Ronca concludes, the benefits are accessible to everyone. "Some of our previous studies have shown that 15 minutes of moderate activity is enough to boost our mood and cognitive performance," she says. "That’s equivalent to taking a brisk walk around the block or cycling to the shops.” The path to a quicker, sharper brain isn’t found by tracking your cycle, but by lacing up your shoes.
Reference
Ronca, F., Watson, E., Falla, M., Földes, E., Jones, B., Dikomiti-Kori, D., Solomons, M., & Moore, J. P. (2024). Menstrual cycle and athletic status interact to influence symptoms, mood, and cognition in females. Sports Medicine – Open, 10(1), 68. https://doi.org/10.1186/s40798-024-00733-z
