Analysis of heart rate variability in submaximal exercise in people with obstructive sleep apnea

Abstract

Obstructive Sleep Apnea Syndrome (OSAS) is a respiratory disorder characterized by dysfunctions in the autonomic nervous system (ANS). However, the impacts on the exercise performance in heart rate variability (HRV) in these patients remains unclear. It is an observational transversal study, which included patients diagnosed with OSAS, aged over 18 of both sexes. HRV was collected with a Smart Lab HRV heart rate monitor (HMM Group, Heidelberg, Germany) during submaximal exercise testing with 6 minutes step test (6MST), which included 3 stages: pre-exercise, during exercise and post-exercise. Data were analyzed posteriorly in Kubios HRV Scientific Lite software (KUBIOS OY, Finland), in which time and frequency domain data of HRV analyses were obtained for each person. 30 volunteers were recruited, with a mean age of 53.27±13.47 years and 56.6% male. There was statistical difference between pre, during and post exercise values of all frequency domain data (LF Power and HF Power; p= <0,05), except for Ratio LF/HF (p = 0.096) and between pre and exercise and exercise and post exercise for all time domain data (SDNN, RMSSD and TINN). In time domain, there wasn’t difference between pre and post exercise values in any variable. In people with OSAS, frequency and time domain values reduced during the exercise phase, which means greater sympathetic activity. There wasn’t difference between pre and post exercise phase in time domain variables, which means fast recovery in patients with OSAS.