Table 1.
Baseline characteristics of participants
| Characteristic | Sleep restriction (n= 46) Mean (SD) | Control (n= 51) Mean (SD) |
|---|---|---|
| Age, years | 55.4 (12.7) | 51.8 (13.4) |
|
| ||
| Female, n (%) | 39 (85) | 36 (71) |
|
| ||
| Duration of insomnia, years | 15 (14) | 14 (13) |
|
| ||
| Primary outcomes | ||
|
| ||
| Pittsburgh Sleep Quality Index25 | 10.43 (3.08) | 10.29 (3.02) |
|
| ||
| Insomnia Severity Index26 | 14.76 (3.85) | 14.51 (3.36) |
|
| ||
| Sleep efficiency [sleep diary],a % | 73.32 (11.80) | 74.15 (11.05) |
|
| ||
| Sleep efficiency [actigraphy], % | 82.68 (4.66) | 82.37 (4.67) |
|
| ||
| Secondary outcomes — sleep | ||
|
| ||
| Epworth Sleepiness Scale31 | 5.17 (3.70) | 6.45 (3.29) |
|
| ||
| Flinders Fatigue Scale32 | 12.74 (6.83) | 12.53 (5.11) |
|
| ||
| Sleep-onset latency, minutes | ||
| Sleep diary | 31.50 (23.00) | 29.55 (22.48) |
| Actigraphy | 16.10 (14.47) | 14.66 (12.42) |
|
| ||
| Wake after sleep onset, minutes | ||
| Sleep diary | 44.82 (28.92) | 47.84 (30.14) |
| Actigraphy | 47.59 (13.88) | 51.81 (19.51) |
|
| ||
| Total sleep time, minutes | ||
| Sleep diary | 369.59 (65.27) | 376.93 (61.08) |
| Actigraphy | 415.68 (34.17) | 418.36 (39.36) |
|
| ||
| Secondary outcomes — mental health | ||
|
| ||
| PHQ-9 depression score33 | 4.98 (2.76) | 5.31 (2.80) |
|
| ||
| GAD-7 anxiety score34 | 3.33 (3.06) | 3.41 (2.45) |
|
| ||
| Physiological measures | ||
|
| ||
| Systolic blood pressure, mmHg | 122.24 (13.98) | 123.88 (13.20)b |
|
| ||
| Diastolic blood pressure, mmHg | 75.52 (10.35) | 75.62 (8.98)b |
|
| ||
| Heart rate, beats per minute | 68.91 (9.82) | 73.29 (10.86) |
|
| ||
| Body mass index, kg/m2 | 25.84 (3.89) | 25.16 (4.28) |
a
Using data averaged from sleep diary recordings for a 2-week period. Sleep efficiency is calculated as total sleep time/time spent in bed × 100%.
b
n = 50 due to equipment malfunction. PHQ-9 = Patient Health Questionnaire-9. GAD-7 = Generalised Anxiety Disorders-7.