The data presented in this study demonstrate a significant association of a common b 2 -AR polymorphism, Arg16Gly, with the non-randomness index, a nonlinear HRV measure derived from the IBS method. Moreover, we illustrate that a bottom-up approach using the IBS method was able to measure the dissimilarity of heart rate dynamics among individuals, and we show that the resulting clusters were associated with b 2 -AR Arg16Gly genotype, indicating an impact of this b 2 -AR polymorphism on acceleration/deceleration patterns of heart rate oscillations.