Current sports science judgments of exercise intensity and fatigue mostly rely on the interpretation of specific values (such as ventilation threshold, and blood lactate concentration) or the personal experience of coaches. Several recent studies support that exercise intensity and fatigue can be determined by the degree of variability in heart rate. AI video-based heart rate measurement captures the heart rate information in real-time without additional device burden, utilizes big data to analyze the current exercise intensity and performance during exercise, and gives appropriate exercise suggestions or warnings.