Improving Sleep With the Far-infrared Emitting Pyjamas

The aim of this study is to explore the effects of a far-infrared emitting pyjamas on improving sleep in adults with poor sleep.

Objectives: To explore the effects of a far-infrared emitting pyjamas on improving sleep in adults with poor sleep. Hypothesis: Subjects who wear the far-infrared emitting pyjamas (FIR pyjamas) will have greater improvement in sleep quality than the subjects in sham pyjamas control group (sham-pyjamas) at 2, 4 and 6 weeks. Design and subjects: A pilot randomized sham-controlled trial. Subjects with subjective sleep complaints will be recruited from the community. 40 subjects will be randomized to far-infrared emitting pyjamas and sham-pyjamas groups in a 1: 1 ratio. Study instrument: Pittsburgh Sleep Quality Index (PSQI) will be used as an overall evaluation of sleep quality. Interventions: Subjects in the FIR pyjamas group will received pyjamas with far-infrared emitting features and will wear it every night for 6 weeks; subjects in the sham-pyjamas group will receive pyjamas in identical appearance without far-infrared emitting features. Outcome measures: The primary outcome measure is the PSQI score. Other measures include insomnia severity index (ISI), sleep parameters derived from 7-day sleep diary, Hospital Anxiety and Depression Scale (HADS), Epworth Sleepiness Scale (ESS) and Satisfaction With Life Scale (SWLS) at 2, 4 and 6 weeks. Acceptability of the far-infrared emitting pyjamas will also be evaluated. Data Analysis: Differences in the questionnaire scores, subjective sleep parameters will be examined using a mixed-effects model. Clinical significance of sleep improvement between two groups will be compared with chi-squared test.

Subjects in this group will be provided the Far-infrared emitting pyjamas. The FIR pyjamas was fabricated by using two textile materials, pure cotton fibres and the proposed man-made FIR fibres with the far-infrared emitting function.

To control the placebo effect in the FIR pyjamas group, participants in this group will receive pyjamas with identical physical appearance which are produced using the same fabrication process as the pyjamas received in FIR pyjamas group. The sham-pyjamas are made of pure cotton fibres and man-made fibres without the far-infrared emitting function. The participants will be asked to wear the sham-pyjamas daily at night for 6 consecutive weeks.

Clothing made in far infrared (FIR) - based textiles could be a sustainable way for alleviating sleep problems with many advantages. Firstly, the proposed far infrared textiles are made of man-made profiled fibers without the addition of chemicals such as ceramic additives or other related coatings.

The sham-pyjamas are made of pure cotton fibres and man-made fibres without the far-infrared emitting function.

The PSQI is a self-reported evaluation of the overall sleep quality. Subjects will be asked to report the sleep parameters of their sleep problem, use of sleep medicine, disturbance, and daytime dysfunction with 0-3 rating. The time frame of PSQI adopted in this study will be changed from "past 1 month" to "past 2 weeks". The PSQI is a reliable and validated tool widely used in sleep studies.

The ISI is a seven-item self-rating scale. The subjects rate the severity of insomnia, the distress, and the functional impairment associated with insomnia on a 5-point Likert scale. The ISI is a validated instrument which has been commonly used in clinical trials of insomnia.

The standardized sleep diary records the bedtime and rising time, from which the total time in bed (TIB) can be calculated. Subjects will be asked to estimate sleep-onset latency, wake after sleep onset, and total sleep time (TST). They will also rate their sleep quality on a 4-point scale (very good, fairly good, fairly bad, and very bad).

The HADS is a 14-item self-administrated questionnaire, which assess the severity of depressive and anxiety symptoms

The ESS is a self-rated questionnaire assessing the level of daytime sleepiness in eight common daily activities. The ESS is a self-administered questionnaire with 8 questions. Respondents are asked to rate, on a 4-point scale (0-3), their usual chances of dozing off or falling asleep while engaged in eight different activities. Most people engage in those activities at least occasionally, although not necessarily every day. The ESS score (the sum of 8 item scores, 0-3) can range from 0 to 24. The higher the ESS score, the higher that person's average sleep propensity in daily life (ASP), or their 'daytime sleepiness'. The questionnaire takes no more than 2 or 3 minutes to answer.

The score of SWLS is found to predict mental health which has been used for assessing subjective well-being of subjects with health conditions. Scores consist of a raw score (between 5 and 35). Higher scores represent higher life satisfaction. Scorers can be assigned into six well-being categories and interpretative text in provided for each.

MFI is a 20-item scale designed to evaluate five dimensions of fatigue: general fatigue, physical fatigue, reduced motivation, reduced activity, and mental fatigue. In an initial psychometric evaluation, developers reported an internal consistency ranging from .53 to .93. The scale was also found to be sensitive to differences between the participant groups.

Inclusion Criteria: Chinese Hong Kong residents who are able to read Chinese; Aged 18 - 65 years; Subjective sleep complaints of having difficulties in falling asleep, difficulties in staying asleep, or early morning awakening with consequences for daily life for at least 3 months. Pittsburgh Sleep Quality Index total score of at least 5 indicating sleep disturbance with 89.6% sensitivity and 86.5% specificity; and Willing to give informed consent and comply with the trial protocol. Exclusion Criteria: Currently receiving psychotherapy or participating in other clinical trials for insomnia; Pregnancy; Shift workers; At significant suicidal risk as rated by the Hamilton Depression Rating Scale item on suicide (score ≥ 3); No comorbid sleep disorders primarily requiring other treatment, such as sleep apnea or narcolepsy; and Taking herbal remedies, over-the-counter medication, or psychotropic drugs that target insomnia within the 2 weeks prior to baseline.