RecruitingBehavioural interventionOptimizing an Integrated Mind and Body Treatment for Insomnia: The SLEEPS Study 2This two-arm randomized trial will provide digital cognitive behavioral therapy for insomnia (CBT-I) to all participants and passive body heating (PBH) sessions using a sauna blanket to half of participants over a 9-week treatment period. Participants are adults aged 18 years or older with insomnia disorder.