In the Olympic questions series, researchers from the University of Twente explore how technology, data and human behaviour come together in elite sport. This story shows how menstruation and hormonal fluctuations are still often missing from sports data, and why more inclusive design of wearables and health technologies is needed to better understand both performance and wellbeing.
At the same time, one topic still frequently remains overlooked in elite sport: menstrual cycles. While athletes increasingly track everything from sleep and recovery to heart rate, the menstrual cycle often remains a taboo, both in conversations with coaches and in the way technology is designed.
For Armağan Karahanoğlu, associate professor of Interaction Design at the University of Twente, this issue touches the core of her research: how do you design sports technology that reflects real human experiences rather than male averages?
Data is becoming increasingly important in elite sport
Wearables and tracking apps have become standard tools in elite sport. Training load, sleep and recovery are closely monitored to optimise performance. Yet not everything can be easily captured in numbers.
Research shows that many female elite athletes experience physical or mental effects linked to their menstrual cycle, yet conversations about this are far from routine. In particular, there is still hesitation when it comes to discussing the topic with male coaches.
As a result, part of the physiological context in which performance takes place can be missing, even in an environment built around data.
Why menstrual cycles are still missing from data
According to Karahanoğlu, one reason is simply complexity.
“Menstrual cycles are much more complex to track than steps or heart rate”, she explains. “They are multi-dimensional, they vary from person to person, and they fluctuate from month to month.”
While many tracking apps exist, there is still no shared gold standard for measuring or modelling menstrual cycles in ways that are both reliable and meaningful for sports performance. In recent research conducted at the University of Twente, this lack of common methodology became clear.
“Because the data is messy and difficult to standardise, technology developers often avoid integrating it”, says Karahanoğlu. “It is easier to design systems around stable metrics than around cyclical experiences.”
Designing technology for real bodies
For Karahanoğlu, this is not only a sports issue but also a design challenge. Her research focuses on personal health technologies and on how people make sense of their own health data.
“Health technology should not frustrate or stigmatise users, but connect with sensitive human experiences”, she says.
The same applies to sports tracking. Many systems are designed around mostly male averages and fixed goals, more steps, better scores, higher intensity, while the human body does not always function in a linear way.
“When technology ignores hormonal fluctuations, it risks producing incomplete interpretations of performance,” she explains. Hormonal changes can influence energy levels, recovery and perceived exertion, while training load itself can also affect menstrual regularity.
“If that context is missing, the technology may interpret a lower performance score as poor recovery or reduced effort, while in reality it reflects a physiological phase. That can lead to inappropriate advice or unnecessary psychological pressure.”
More measurement is not always better
Self-tracking has provided athletes with significant insights, but researchers also point to a risk: data without context.
Karahanoğlu investigates how technology can help people understand data rather than be controlled by it. This requires designs that allow space for reflection and personal interpretation, not only for performance optimisation, but also for wellbeing.
From her perspective, the issue is bigger than a technical limitation. “This is not just a data gap,” she says. “It is a bias in how the body is modelled.”
From elite sport to everyday life
Although the discussion often starts with Olympic athletes, the issue reaches far beyond elite sport. Millions of women use smartwatches and apps to guide decisions about exercise, sleep and productivity. Yet these systems rarely account for differences in bodily experience.
“It is important to recognise that hormones influence how we feel, move and perform — not just in elite sport, but in everyday life,” says Karahanoğlu.
If technology presents data as fully objective without acknowledging variation, users may interpret fluctuations as personal failure. “The broader lesson is that data always needs context,” she explains. “Technology should support understanding, not enforce rigid performance norms.”
A future with more empathetic wearables
With the Winter Olympics as a stage, it becomes clear how far sports data has progressed. At the same time, the debate around menstrual cycles highlights that there is still room for innovation, not only in sensors, but in designing technology that is more empathetic and inclusive.
For Karahanoğlu, the future wearable will look very different from today’s devices. “An ideal wearable would not simply display numbers,” she says. “It would help users interpret those numbers, explain uncertainty, and recognise variation as normal.”
Reaching that point will require collaboration across disciplines, from sports physiology and data science to interaction design grounded in women’s lived experiences.
“That is exactly where design and science meet,” Karahanoğlu says. “Technology should not just measure performance; it should help people understand themselves.”
