Abstract
Background: Heart rate variability (HRV) is affected by respiration, circadian factors, environmental factors, yoga, and exercises. There are emerging reports of myocardial infarction in young adults. Reduced HRV is a sign of poor autonomic function. Sedentary life habits in the younger generation have become an important issue in consideration along with the unmodifiable risk factors such as aging and hormonal influences. Several studies have shown that young obese males have reduced HRV. However, there are not many studies, which have explored the changes in HRV indices in young females with higher body mass index (BMI).

Aims and Objectives: The aim of this study was to assess and compare the HRV status of young women with higher BMI and women with normal BMI.

Materials and Methods: A total of 40 apparently healthy females of age between 18 and 25 years were recruited in the study. Sedentary behavior was assessed using the International Physical Activity Questionnaire. According to BMI (WHO guidelines for Asian population), subjects were divided into test group (BMI >23 kg/m2 and waist/hip [W/H] ratio >0.8, n = 20) and control group (BMI = 18-23 kg/m2, W/H ratio <0.8 n = 20). The subjects were made to lie in supine position for 10 minutes and then 5 min electrocardiogram was acquired in lead II configuration following Task Force Guidelines. After screening for ectopic beats and noise, time domain and frequency domain analysis of the data were done using the Kubios HRV analysis software. Mann Whitney U test was used to test for any significant differences between the groups using the SPSS software version 20.

Results: There was no significant differences in the time domain analysis data between the test group and the control group does not show any significant differences. Under frequency domain analysis, low-frequency normalized units (LF nu) is significantly higher (P = 0.043), high-frequency (HF) nu is significantly lesser (0.043), and LF/HF ratio is significantly higher (P = 0.05) in the test group as compared to the control group. This implies that there is predominance of sympathetic activity in the young overweight and obese females.

Conclusion: Apparently healthy young females, who are overweight and obese, have reduced HRV, which is an alarming signal in today’s scenario, wherein we have reports of cardiovascular morbidities and mortalities at an earlier age. This urges us to think if we have to establish HRV analysis as a prophylactic investigation and also to emphasize on earlier adoption of lifestyle modifications to prevent the progress of impending alterations in the cardiovascular status of these young women.

Key words: Heart Rate Variability; Sedentary Females; Sympathetic Overactivity