Schmidt JE, et al. - In this work, researchers aimed at exploring whether changes in respiratory rate (RR) alone resulted in autonomic changes during normal, paced, and mechanically assisted breathing in untrained fibromyalgia (FM) patients and controls. Findings revealed that FM patients had markedly reduced heart rate (HR) with higher heart rate variability and spontaneous baroreceptor sensitivity variables during mechanically assisted breathing, compared to the paced breathing condition. However, no significant change in RR were evident between the two breathing condition. In untrained FM patients, mechanically assisted breathing was more beneficial in terms of autonomic function than paced breathing.