Table 3.
Night 1 (baseline sleep) heart rate variability (HRV) measures for subjects with and without frequent nightmares
| Nightmare (N = 16) |
Control (N = 11) |
Group comparisons (P)† |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Time domain | REM | St 2 | Awake | REM | St 2 | Awake | REM | St 2 | Awake | |
| HR | M | 66.8 | 62.2 | 64.5 | 63.6 | 60.9 | 63.0 | ns | ns | ns |
| SD | 12.5 | 11.7 | 10.9 | 6.7 | 5.8 | 7.0 | ||||
| SDNNa | M | 71.3 | 60.6 | 55.7 | 77.8 | 67.9 | 58.9 | ns | ns | ns |
| SD | 38.8 | 35.5 | 28.5 | 38.0 | 29.5 | 29.7 | ||||
| pNN50b | M | 11.0 | 13.0 | 12.6 | 14.7 | 19.1 | 16.4 | ns | ns | ns |
| SD | 8.1 | 8.6 | 9.6 | 9.4 | 8.7 | 10.8 | ||||
|
Frequency domain: Absolute | ||||||||||
| VLF | M | 1416.4 | 693.1 | 552.4 | 1160.4 | 629.6 | 172.9 | ns | ns | ns |
| SD | 1834.3 | 483.2 | 693.0 | 856.2 | 383.0 | 233.2 | ||||
| LF | M | 2095.6 | 1527.0 | 1304.6 | 1875.7 | 1547.2 | 809.4 | ns | ns | ns |
| SD | 2736.7 | 1544.3 | 2116.1 | 1599.8 | 1536.8 | 578.3 | ||||
| HF | M | 2070.3 | 2024.8 | 1542.1 | 2622.0 | 2790.9 | 2299.8 | ns | ns | ns |
| SD | 3612.1 | 3333.3 | 2307.8 | 2977.7 | 3375.7 | 3081.5 | ||||
|
Frequency domain: Normalized | ||||||||||
| LFnuc | M | 56.0 | 44.0 | 42.8 | 45.3 | 34.2 | 28.6 | 0.069 | 0.069 | ns |
| SD | 13.6 | 11.1 | 17.2 | 10.3 | 12.4 | 18.2 | ||||
| HFnuc | M | 36.8 | 47.9 | 51.4 | 47.6 | 56.7 | 65.2 | ns | ns | ns |
| SD | 13.9 | 10.9 | 18.1 | 12.1 | 12.9 | 17.4 | ||||
| LF/HF | M | 2.9 | 1.6 | 1.5 | 1.4 | 1.0 | 0.7 | 0.069 | ns | ns |
| SD | 2.0 | 0.9 | 1.3 | 1.0 | 0.9 | 0.7 | ||||
†
2-tailed, univariate F-tests, P-values > 0.08 not displayed;
a
SDNN = standard deviation of R-R intervals;
b
pNN50 = proportion of R-R intervals differing from preceding interval by ± 50msec;
c
Normalized values calculated as a proportion of total power minus VLF