Table 2.
Correlations Between HRV, HRR, and Heart Rate Dynamics (n = 91).
| SDNN | SDNN index | RMSSD | NN50 | HRR | Minimum resting HR | Maximum resting HR | Average resting HR | |
|---|---|---|---|---|---|---|---|---|
| SDNN (ms) | — | 0.763** (0.748**) | 0.349** (0.423**) | 0.684** (0.700**) | 0.207 (0.185) | −0.797** (−0.777**) | 0.241* (0.191 | −0.575** (−0.609**) |
| SDNN index (ms) | — | — | 0.381** (0.389**) | 0.816** (0.796**) | 0.371** (0.310**) | −0.770** (−0.752**) | 0.031 (−0.046) | −0.600** (−0.631**) |
| RMSSD (ms) | — | — | — | 0.531** (0.523**) | 0.235* (0.144) | −0.280** (−0.302**) | 0.013 (0.059) | −0.305** (−0.260*) |
| NN50 (%) | — | — | — | — | 0.291* (0.207) | −0.691** (0.692**) | 0.034 (−0.033) | −0.540** (−0.556**) |
| HRR (bpm) | — | — | — | — | — | −0.255* (−0.223*) | 0.030 (0.031) | −0.245* (−0.205) |
| Minimum resting HR (bpm) | — | — | — | — | — | — | 0.005 (0.054) | 0.644** (0.658**) |
| Maximum resting HR (bpm) | — | — | — | — | — | — | — | 0.274* (0.277*) |
| Average resting HR (bpm) | — | — | — | — | — | — | — | — |
Note. *denotes significance value <0.05; **denotes significance values <0.01; () values reflect Spearman correlations adjusted for the following covariates: age, race (white/non-white), sex (male/female), body mass index (BMI).