Table 1.
Characteristics of study participants by quartile of heart rate variability (SDNN) from the Deep Breathing Test.
| Characteristics | All participants N = 101 | Quartiles of SDNN | p-value | |||
|---|---|---|---|---|---|---|
| N = 25 | N = 26 | N = 25 | N = 25 | |||
| SDNN (ms) | 53.5 ± 32.7 | 19.7 ± 5.1 | 36.5 ± 5.9 | 57.7 ± 6.2 | 100.9 ± 22.2 | |
| Age (years) | 60.4 ± 13.4 | 70.6 ± 10.9 | 61.6 ± 11.7 | 59.4 ± 9.3 | 49.9 ± 13.2 | <0.001 |
| Men, n % | 46 (45.5) | 7 (28.0) | 12 (46.2) | 13 (52.0) | 14 (56.0) | 0.20 |
| Race, n % | 0.80 | |||||
| White | 96 (95.0) | 24 (96.0) | 25 (96.2) | 24 (96.0) | 23 (92.0) | |
| Black | 4 (4.0) | 1 (4.0) | 1 (3.8) | 1 (4.0) | 1 (4.0) | |
| Other | 1 (1.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 1 (4.0) | |
| BMI (kg/m2) | 27.7 ± 4.4 | 28.4 ± 4.9 | 28.3 ± 4.3 | 27.3 ± 4.5 | 27.0 ± 3.9 | 0.58 |
| WHR | 0.9 ± 0.1 | 0.9 ± 0.1 | 0.9 ± 0.1 | 0.9 ± 0.1 | 0.9 ± 0.1 | 0.62 |
| Smoking | 16 (15.8) | 4 (16.0) | 6 (23.1) | 4 (16.0) | 2 (8.0) | 0.54 |
| HTN | 48 (47.5) | 16 (64.0) | 12 (48.0) | 12 (48.0) | 8 (32.0) | 0.16 |
| DM | 17 (16.8) | 6 (24.0) | 4 (15.4) | 5 (20.0) | 2 (8.0) | 0.47 |
| SBP supine (mmHg) | 137.0 ± 17.6 | 145.7 ± 18.8 | 137.8 ± 19.2 | 135.5 ± 13.3 | 129.0 ± 15.1 | 0.007 |
| SBP standing (mmHg) | 129.1 ± 17.0 | 135.2 ± 16.8 | 130.0 ± 20.1 | 127.5 ± 15.1 | 123.5 ± 14.1 | 0.09 |
| DBP (mmHg) | 78.4 ± 10.5 | 79.3 ± 10.7 | 78.3 ± 13.0 | 78.3 ± 9.7 | 78.0 ± 8.2 | 0.97 |
| LVEF (%) | 67.8 ± 4.4 | 69.5 ± 5.4 | 65.9 ± 3.9 | 68.7 ± 3.9 | 67.1 ± 3.3 | 0.01 |
| TC (mg/dl) | 191.2 ± 39.4 | 190.7 ± 41.3 | 191.4 ± 38.5 | 189.4 ± 39.9 | 193.3 ± 40.2 | 0.99 |
| HDL (mg/dl) | 46.3 ± 9.6 | 47.3 ± 10.5 | 43.1 ± 8.1 | 48.0 ± 10.2 | 47.0 ± 9.0 | 0.25 |
| LDL (mg/dl) | 113.0 ± 35.9 | 110.5 ± 35.3 | 113.6 ± 33.7 | 108.8 ± 38.6 | 119.2 ± 37.2 | 0.75 |
| ASCVD risk score | 16.4 ± 17.5 | 27.3 ± 17.2 | 19.0 ± 22.3 | 10.9 ± 10.3 | 8.2 ± 10.7 | <0.001 |
| IMT (mm) | 0.80 ± 0.20 | 0.90 ± 0.19 | 0.82 ± 0.21 | 0.81 ± 0.16 | 0.68 ± 0.19 | 0.001 |
Numbers represent N (%) or Mean ± SD. SDNN, standard deviation of all RR intervals; BMI, body mass index; WHR, waist-hip-ratio; HTN, hypertension; DM, diabetes mellitus; SBP, systolic blood pressure; DBP, diastolic blood pressure; LVEF, left ventricular ejection fraction; TC, total cholesterol; HDL, high-density lipoprotein; LDL, low-density lipoprotein; ASCVD, atherosclerotic cardiovascular disease, IMT, carotid intima media thickness.