Specific heart rate variability features in four ethnic groups of young adults residing in the United States: Association with socioeconomic status

Previous research has demonstrated different associations between ethnicity and resting measures of heart rate variability (HRV), an important proxy of an organism's autonomic regulatory pathways, particularly between non-Hispanic Black (NHB) and non-Hispanic White (NHW) adults in the United States. The current study aimed to extend the investigation of differences in HRV to four ethnic groups through a social lens, by examining the impact of socioeconomic status (SES) on the relation between ethnicity and HRV. Time- and frequency-domain indexes of HRV were collected during a 10-min period in 944 young adults (n = 175 Asian, n = 77 NHB, n = 208 Hispanic, n = 484 NHW). After adjusting for several covariates, NHB adults had higher resting values of high-frequency HRV compared to the other ethnic groups, specifically at mean and low estimates of SES. In NHB adults only, SES negatively correlated with HRV metrics. Also, Asian adults showed lower resting values of the standard deviation of inter-beat-intervals, and NHW adults had higher resting values of low-frequency HRV compared to the other ethnic groups. These ethnic differences were consistent among women and men. This study provides evidence of specific HRV features and their association with SES in four ethnic groups of young adults residing in the United States, which may have implications for our understanding of the role of social factors in autonomic regulatory processes in individuals of different ethnic groups.