Cardiac autonomic regulation during submaximal exercise in women with fibromyalgia

Abstract

Fibromyalgia (FM) patients present impaired cardiac autonomic regula-tion during maximal exercise; however, it is unknown whether these al-terations also manifest during submaximal exercise. The aim of this study was to compare the on-transient heart rate (HR) response and HR variability during a constant-load submaximal cycling exercise between FM and control (CON) women. Ten women with FM (age: 45.2±9.3 years) and 10 age-matched CON women (age: 48.4±6.1 years) performed a 15-min cycling exercise, with the work rate fixed at 50% of the individual peak power output attained in a maximal graded exercise test. The time intervals between consecutive heartbeats were recorded regularly during the exercise for subsequent analysis of on-transient HR response and HR variability indices. The on-transient HR time constant was simi-lar (p=0.83) between the FM (41.0±14.1 sec) and CON (42.2±10.4 sec). During the 5–10 and 10–15 min of exercise, HR variability indices indi-cating sympathetic and parasympathetic activities were similar (p>0.05) between FM and CON groups. In conclusion, women with FM present-ed a normal cardiac autonomic response to submaximal cycling exer-cise. These findings have clinical relevance, as submaximal exercises are commonly prescribed for FM patients.