Measuring football fever through wearable technology: A case study on the German cup final

Football is the world’s most popular sport, evoking strong physiological and emotional responses among its fans. Yet, the specific dynamics of fan attachment to matches have received little attention in the literature. In this paper, we quantify these dynamics through a unique case study from professional football: the 2025 cup final of the German Football Association (DFB) between first-division club VfB Stuttgart and third-division club Arminia Bielefeld. We collected high-resolution smartwatch data, including heart rate and stress level, from 229 Arminia Bielefeld fans over approximately 12 weeks, complemented by survey responses on club attachment, match attendance, and personal characteristics from a subset of 37 participants. By combining physiological data with survey information, we analyse variations in emotional engagement across individuals and contexts, as well as physiological reactions to key match events. This approach provides rare, data-driven insights into the football fever that captivates fans during high-stakes competitions. Furthermore, we compare the vital parameters recorded on the day of the match with baseline levels on non-matchdays throughout the entire observation period. Our findings reveal pronounced physiological responses among fans, beginning hours before the match and peaking at kick-off.

💡 Research Summary

The paper investigates physiological and emotional responses of football fans during a high‑stakes sporting event by leveraging wearable technology. The authors focused on the 2025 German Football Association (DFB) Cup final, in which third‑division club Arminia Bielefeld faced first‑division side VfB Stuttgart. A total of 229 self‑identified Arminia supporters were recruited to wear Garmin smartwatches for approximately twelve weeks, from 14 May 2025 to 31 July 2025. The devices recorded heart rate at 15‑second intervals and a proprietary “stress level” metric (scale 0–100) at three‑minute intervals, the latter derived from heart‑rate variability (HRV) and suppressed during periods of high physical activity.

In parallel, a structured questionnaire was distributed to 95 participants who consented to further contact; 37 completed the survey within the stipulated 16‑day window. The survey captured demographic variables (age, gender), fan‑related characteristics (club membership, season‑ticket ownership, number of matches attended in person during the 2024/25 season), match‑viewing context (stadium, public gathering, television), and alcohol consumption during the final. Among the respondents, 20 attended the match in Berlin, 5 joined public viewings, and 11 watched on TV. Half reported drinking alcohol, with a higher proportion (65 %) among stadium attendees.

The analysis proceeded in three stages. First, descriptive statistics were computed for stress level and heart rate on the day of the final (24 May 2025) and on “regular days” (all non‑match, non‑holiday days within the observation window). On the final day, the mean stress score was 45.3 (median 44.2), representing a 42 % increase over the regular‑day mean of 31.1. The mean heart rate rose to 78.7 bpm compared with 70.9 bpm on regular days. Maximum stress values reached 90 on the final day, whereas the highest regular‑day value was around 50, indicating considerable individual variability.

Second, time‑series visualisations revealed that average stress began to climb around 06:00 h on the final‑day, peaked just before kickoff (08:00 h), and remained elevated for roughly an hour after the final whistle. Night‑time (22:00–02:00) stress levels were consistently low across the entire study period, reflecting typical sleep patterns. Weekly patterns showed that Saturdays generally exhibited higher stress than weekdays, likely due to broader social activities unrelated to football.

Third, the authors linked physiological outcomes to survey variables. Club members and season‑ticket holders displayed 8–12 % higher average stress and heart rate than non‑members. Stadium attendees showed higher peak stress (≈15 % greater) than TV viewers, and participants who reported alcohol consumption exhibited modestly higher stress scores. Moreover, all respondents who attended more than ten matches in person during the season also attended the final in the stadium, suggesting a strong relationship between prior in‑person engagement and physiological arousal during a marquee event.

The study’s strengths include a relatively large sample size for a fan‑physiology investigation, a long baseline period that permits differentiation between event‑specific and routine physiological fluctuations, and high‑resolution wearable data that enable fine‑grained temporal analysis. However, limitations are acknowledged: the stress metric is an indirect HRV‑derived estimate and may not capture hormonal stress responses (e.g., cortisol); data gaps occurred when participants removed the watch or when high activity suppressed stress readings, potentially biasing results during moments of intense cheering; and the survey response rate (37/95) limits the generalisability of the covariate analyses.

In the discussion, the authors compare their findings with prior laboratory‑based studies that reported heart‑rate and blood‑pressure spikes among spectators of high‑intensity matches (van der Meij et al., 2012; Newson et al., 2020). They argue that wearable technology allows for ecological validity—capturing fans in their natural environments over weeks rather than in short, controlled sessions. The observed pre‑match stress rise aligns with literature on “pre‑game rituals” that generate anticipatory arousal, while the post‑match persistence of elevated stress may reflect emotional processing of the outcome.

Future research directions proposed include integrating multimodal biosignals (electrocardiography, blood pressure, salivary cortisol), employing real‑time self‑report emotion scales, and extending the methodology to other sports (basketball, rugby) and cultural events (concerts, political rallies) to test the universality of the “fan fever” phenomenon.

In conclusion, the paper demonstrates that smart‑watch derived heart‑rate and stress data, combined with targeted surveys, can quantitatively capture the physiological imprint of football fandom during a nationally significant match. The results have practical implications for sports marketers, event organizers, and public‑health officials interested in managing crowd stress, optimizing fan engagement strategies, and understanding the health impacts of intense spectator experiences.