Investigation of the involvement of body composition in heart rate dynamics during recovery from submaximal physical exercise and muscle isometric contraction in physically active subjects

Abstract

The autonomic regulation of the heart rate in recovery from exercise and voluntary isometric contraction can provide information that system that are not detected at rest. Among the factors influencing the autonomic control of heart rate on exertion are included body mass index (BMI) and fat mass. However, it is unclear whether in healthy subjects the hemodynamic response in the recovery effort differs between subjects of anthropometric factors and with different body compositions, however, within the normal range. Objective: To analyze the involvement of body composition in dynamic heart rate recovery from exercise and isometric muscle contraction. Method: The study will be conducted in young adults of both sexes, 18-35 years old. Volunteers will be divided into groups according to sex: 1. Body mass index between 25 and 30 kg / m2; 2- body mass index between 20 and 25 kg / m2; 3- taper index between 1 and 1.25; 4 taper Index <1; 5- Women with fat percentage between 15% and 19%; 6- Women with fat percentage between 20% and 25%; 7- men with fat percentage between 10% and 15%; 8 Men with fat percentage between 15% and 20%. They will not be analyzed in individuals with cardiorespiratory disorders, neurological and other reported impairments that prevent them from performing the procedures, as well as those who are on medication that influences the autonomic nervous system. Linear indices in the time domain and the frequency of heart rate variability (HRV) and Poincaré plot analysis and symbolic will be analyzed. The groups will perform an aerobic exercise protocol with a speed of approximately 60% of the maximum speed achieved in maximal exercise test as Conconi threshold. The cardiovascular parameters will be analyzed before and after exercise. In voluntary isometric contraction protocol, contractions will be performed using an analog dynamometer grip and perform manual isometric hold 40% of the maximum power for 3 minutes seconds. The cardiovascular parameters will be analyzed before and after voluntary isometric contraction protocol. (AU)