Sleep Quality and Quality of Life in Older Patients with Hypertension after Night-Time Hot Spring Bathing: A Single-Institution Intervention Study

Habitual night-time hot spring bathing, which is practiced to improve sleep disorders, is inversely associated with hypertension in adults aged ≥ 65 years. This study aimed to explore a nondrug intervention for insomnia by evaluating the effects of night-time hot spring bathing on sleep quality and quality of life (QOL) in older patients with hypertension. This prospective study evaluated the effects of night-time hot spring bathing on patients with primary hypertension (n = 28) aged 65 years or older (Japan Registry of Clinical Trials registration number: UMIN000051274). Between July 1, 2023, and February 29, 2024, participants were invited to a 1- to 3-day sleep promotion experience at our institute, which included night-time hot spring bathing and education on exercise and diet. Participants were encouraged to continue sleep-promoting activities during a 3-month follow-up period; sleep quality and QOL questionnaires were completed at 1 and 3 months post-intervention. There was a significant improvement in sleep quality according to the Pittsburgh Sleep Quality Index (p < 0.001). Patients also reported significantly improved QOL according to the SF-36® 1-month post-intervention and a significant improvement in mental health at both 1 and 3 months post-intervention (p = 0.013). Night-time hot spring bathing was significantly associated with improved sleep quality in older hypertensive patients. Prospective randomized controlled trials are needed to investigate whether night-time hot spring bathing can prevent diseases associated with sleep disorders in older adults, such as hypertension.