TABLE 1.
Demographic and clinical characteristics
| MDD (n = 65) | Controls (n = 77) | Overall (n = 142) | |
|---|---|---|---|
| Characteristics | |||
| Gender, male, n (%) | 12 (18.5%) | 24 (31.2%) | 36 (25.4%) |
| Age (years) | 20.7 (2.6) | 20.8 (2.5) | 20.8 (2.6) |
| BMI (kg/m2) | 23.1 (3.5) | 23.5 (4.2) | 23.3 (3.9) |
| VO2peak (mL*kg−1*min−1) | 36.9 (7.0) | 38.7 (8.7) | 37.9 (8.0) |
| BDI-II scorec | 24.1 (8.6) | 8.8 (7.1) | 15.8 (10.9) |
| BAI scorec | 13.4 (8.2) | 7.5 (7.3) | 10.3 (8.2) |
| Comorbidities, n (%)# | 16 (24.6%) | ||
| Autonomic measures | |||
| HR (bpm)b | 78.1 (10.2) | 72.5 (8.7) | 75.0 (9.8) |
| RSA (ms2)a | 6.2 (1.0) | 6.5 (0.8) | 6.4 (1.0) |
| PEP (ms) | 133.1 (13.3) | 137.8 (21.0) | 135.7 (18.0) |
| CABb | −0.3 (1.2) | 0.3 (1.4) | 0.0 (1.3) |
| CAR | −0.1 (1.4) | 0.0 (1.6) | 0.0 (1.5) |
| LF/HF | 2.6 (2.6) | 2.3 (1.7) | 2.4 (2.1) |
| -zPEP/zRSA | 0.8 (10.0) | −1.5 (11.8) | −0.4 (10.9) |
| Respiratory parameters | |||
| Respiratory rate (cycles/min) | 16.5 (3.5) | 15.7 (3.4) | 16.1 (3.5) |
| Respiratory depth | 0.04 (0.07) | 0.03 (0.07) | 0.04 (0.07) |
Note. Values are mean (SD), unless otherwise indicated.
Abbreviations: BAI, Beck Anxiety Inventory; BDI-II, Beck Depression Inventory, 2nd ed.; BMI, body mass index; CAB, cardiac autonomic balance; CAR, cardiac autonomic regulation; HR, heart rate; LF/HF, low frequency/high frequency ratio; MDD, major depressive disorder; PEP, pre-ejection period; RSA, respiratory sinus arrhythmia; VO2peak, peak oxygen consumption; −zPEP/zRSA, ratio of the inverse normalized pre-ejection period to normalized respiratory sinus arrhythmia; cycles/min, respiratory cycles per minute.
p < 0.05
p < 0.01
p < 0.001.
Generalized anxiety disorder (n = 9), substance-related disorders (n = 2), post-traumatic stress disorder (n = 1), panic disorder with agoraphobia (n = 1), social anxiety disorder (n = 1); two participants had two of these comorbidities.