Lower breathing frequencies in personalized slow-paced breathing enhance relaxation and reduce arousal

Among all vital functions, breathing is uniquely under both autonomic and volitional control. This dual control enables conscious recognition and regulation of arousal. While breathwork affects arousal and relaxation, research rarely investigates the impact of specific parameters or individual differences. In a randomized crossover trial (N = 42), university students practiced three 5-min, personalized slow-paced breathing protocols at 40%, 60%, and 80% of their spontaneous breathing frequency. Lower frequencies enhanced subjective relaxation and reduced physiological arousal, as indicated by decreased heart rate, increased heart rate variability, and increased peripheral skin temperature. Lower frequencies also induced a greater shift in prefrontal neurophysiological arousal, with decreased relative delta power and increased relative alpha and beta power. In addition, prior experience with relaxation techniques strengthened subjective benefits, whereas higher anxious-depressive symptoms were associated with greater perceived stress after slow-paced breathing. Personalization and parameter-based optimization of breathing protocols may enhance relaxation during practice and strengthen self-regulatory capacity.