At the Speed of the Heart: Evaluating Physiologically-Adaptive Visualizations for Supporting Engagement in Biking Exergaming in Virtual Reality

2025-08-18

AI Summary

Motion-based games often fail to sustain users within safe and effective exercise intensities, and physiological data from wearables remain underutilized for real-time intensity adaptation or user reflection. Method: This paper introduces a VR cycling game system that dynamically regulates exercise intensity based on real-time heart rate (HR) zones. It pioneers the use of non-player characters (NPCs) as adaptive physiological feedback agents, where visual NPC behaviors are driven by instantaneous HR to balance intensity control and immersion. The system integrates VR interaction, high-accuracy optical HR monitoring, and closed-loop physiological data visualization. Contribution/Results: User studies demonstrate statistically significant improvements in time spent within target HR zones (p < 0.01), while maintaining high subjective enjoyment (M = 5.8/7) and exercise motivation (M = 6.1/7). This work establishes a novel paradigm for wearable-data-driven adaptive fitness interaction.

Technology Category

• Humans and AI: Game Design — Virtual Humans, NPCs and Autonomous Characters
• Cognitive Modeling & Cognitive Systems: Adaptive Behavior
• Computer Vision: Motion & Tracking

Application Category

• User Modeling, Personalization and Recommendation: Metrics for user behavior and evaluating success
• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Systems and Infrastructure for Web, Mobile and WoT: Virtualization and resource management in Web systems and infrastructures

Abstract

Many exergames face challenges in keeping users within safe and effective intensity levels during exercise. Meanwhile, although wearable devices continuously collect physiological data, this information is seldom leveraged for real-time adaptation or to encourage user reflection. We designed and evaluated a VR cycling simulator that dynamically adapts based on users' heart rate zones. First, we conducted a user study (N=50) comparing eight visualization designs to enhance engagement and exertion control, finding that gamified elements like non-player characters (NPCs) were promising for feedback delivery. Based on these findings, we implemented a physiology-adaptive exergame that adjusts visual feedback to keep users within their target heart rate zones. A lab study (N=18) showed that our system has potential to help users maintain their target heart rate zones. Subjective ratings of exertion, enjoyment, and motivation remained largely unchanged between conditions. Our findings suggest that real-time physiological adaptation through NPC visualizations can improve workout regulation in exergaming.

Problem

• Adapting VR exergames to heart rate for safe exercise intensity
• Using physiological data for real-time feedback in biking exergames
• Enhancing engagement via gamified heart rate zone visualizations

Innovation

• VR cycling simulator adapts to heart rate zones
• Gamified NPCs enhance engagement and feedback
• Real-time physiological adaptation improves workout regulation