Effect of a High Intensity Interval Training (HIIT) on Serotonin and Cortisol Levels in Obese Women With Sleep Disorders

Abstract

<strong>Background:</strong> Physical and physiological changes in obese middle-aged women cause hormonal changes, which are threatening factor for quality of life and health of elderly. Objectives : The purpose of this study was to investigate the effect of a one-week HIIT on serotonin and cortisol levels in obese women with sleep disorders. <strong>Methods:</strong> The research method was semi-experimental with pre-test post-test design, in which 34 middle-aged obese women with mean age of 47.11 ± 2.3, body mass index of 33.4 ± 2.7, and body fat percentage of 35.8 ± 2.3 were selected based on convenience sampling. Subjects were randomly divided to experimental groups (HIIT exercises) and control group. The experimental group performed a training program for one week, including three sets of RAST protocol (six bouts of 35 meters with 10 seconds of rest between each) with a four-minute rest between each set. Pittsburgh sleep test was used to diagnose sleep disorders (score 11 and above). Actiwatch 8 was used to evaluate quality of sleep in the post-test. In order to to measure the serotonin and cortisol levels, a serotonin kit from the German company LBL and SSGN kit was used, respectively. Independent and dependent t-test were used for data analysis at P ≤ 0.05. <strong>Results:</strong> The results suggested that cortisol level of HIIT training group was decreased significantly after the exercise intervention (P = 0.01; t = 0.93). On the other hand, the serotonin levels of the HIIT training group was significantly lower (P = 0.001; t = 11.02), while in the control group, the change was not significant (P = 0.15; t = 1.53) and the quality of sleep in the training group was improved significantly (P = 0.001; t = 6.52). <strong>Conclusions:</strong> In conclusion, HIIT exercises can improve the quality of sleep through hormonal changes and as a result, improve the physiological functions of middle-aged women.