Sleep difficulties are common and affect many people worldwide, causing daytime consequences such as fatigue and impaired functioning. Optimizing the sleep environment, including clothing, may help alleviate sleep problems. Far infrared (FIR)-based textiles have been shown to promote blood circulation and improve metabolic function, making them a potential therapeutic alternative for poor sleepers.
In a pilot study, researchers investigated the effects of FIR-emitting pajamas on sleep quality in adults with poor sleep quality. The study was a randomized, sham-controlled trial that included forty subjects randomized to FIR-emitting or sham pajamas in a 1:1 ratio. The primary outcome measure was the Pittsburgh Sleep Quality Index (PSQI). Other measures included the Insomnia Severity Index, a 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. The outcomes were measured at baseline and weeks 2, 4, and 6.
Both groups showed improvements in the PSQI score within their groups, indicating that both FIR-emitting and sham pajamas positively affected sleep quality. However, there was no significant difference between the two groups. Interestingly, FIR-emitting pajamas performed better than sham pajamas in reducing the MFI-physical score. This finding suggests that FIR-emitting pajamas may improve physical fatigue in adults with poor sleep quality. Additionally, the intervention compliance was satisfactory, indicating that participants could use the FIR-emitting pajamas as instructed.