At the start of the 2026 FIFA World Cup, Bielefeld University is looking for fans of all national teams. The Football Fever Study uses smartwatch data to record how match events affect fans' heart rate and stress levels. Anyone wearing a device from one of 13 supported brands, such as Apple, Google, Samsung, and Garmin, can take part.
When the study launched on 28 May, only Garmin devices were eligible. Twelve further brands have been added since: Apple Watch, Google Pixel Watch, Samsung Health, Withings, Fitbit, Oura, Polar, Amazfit, Coros, Whoop, Xiaomi Mi Fitness and Wahoo.
Fans of all national teams are welcome – participants from Eastern and Southern Europe and Turkey are particularly underrepresented. ‘We want to include as many fans as possible, regardless of the nation they support and the smartwatch they wear. More participants lead to more robust data, and that increases the study's explanatory power,’ says Professor Dr Christian Deutscher, co-project leader at Bielefeld University's Faculty of Psychology and Sports Science.
Joining mid-tournament is possible
Fans can join while the tournament is already under way. ‘Anyone who wants to watch a few matches can still take part. Even individual games give us valuable data,’ says Professor Dr Christiane Fuchs, co-project leader and head of the Data Science group at the Faculty of Business Administration and Economics.
The study captures heart rate, stress levels, movement and sleep automatically via their smartwatch. Data are collected anonymously and in compliance with data protection regulations. Those interested can register at
https://uni-bi.de/worldcupfever to take part. The research team plans to publish initial results on the website during the tournament, particularly after matches played by the German national team.
The research is based at Bielefeld University’s Focus Area QUAMU, which brings together work on the quantification of uncertainty. The cooperation partner for the World Cup Fever Study is Bielefeld’s Wissenswerkstadt [Knowledge Hub].
A predecessor study conducted during the 2025 DFB Cup Final with 229 fans of DSC Arminia Bielefeld demonstrated a direct link between match events and vital signs: stadium attendees averaged 94 heartbeats per minute, television viewers 79. After goals, on-site pulse readings were up to 36 per cent higher.