Improving Sleep with Far-Infrared-Emitting Pajamas: A Pilot Randomized Controlled Trial

Far infrared (FIR)-based clothing may alleviate sleep disturbance. This study aimed to explore the effects of FIR-emitting pajamas on sleep quality. This was a pilot randomized, sham-controlled trial. Forty subjects with poor sleep quality were randomized to FIR-emitting-pajamas and sham-pajamas groups in a 1:1 ratio. The primary outcome measure was the Pittsburgh Sleep Quality Index (PSQI). Other measures included the Insomnia Severity Index, and 7 day sleep diary, the Multidimensional Fatigue Inventory (MFI), the Hospital Anxiety and Depression Scale, the Epworth Sleepiness Scale, and the Satisfaction with Life Scale. Outcomes were measured at baseline and weeks 2, 4, and 6. Both groups showed within-group improvements in the PSQI score, but there was no significant difference between the two groups. However, FIR-emitting pajamas appeared to perform better than sham pajamas in reducing the MFI-physical score, with large effect sizes at three time points (dppc2 = 0.958, 0.841, 0.896); however, the differences were statistically insignificant. The intervention compliance was satisfactory. The effects of FIR-emitting pajamas on sleep quality were not superior to those in the control group. However, these pajamas may improve physical fatigue in adults with poor sleep quality, which warrants further exploration.