Three-Week Health Resort Program Eases Insomnia and Boosts Quality of Life Across BMI Categories

A three-week stay at a Polish health resort was followed by meaningful improvements in both insomnia severity and self-rated quality of life among adults spanning normal weight, overweight, and class I obesity, according to a prospective observational study published in Frontiers in Public Health. The researchers, led by Grzegorz Onik of the Medical University of Silesia in Katowice, set out to answer a question that had not previously been examined: whether a person’s body mass index changes how much they benefit from comprehensive sanatorium treatment. Their central finding was that it did not, at least not within the BMI range they studied. Changes in insomnia scores and quality-of-life measures after treatment did not differ significantly across the three BMI groups, although the authors caution that the absence of statistical differences should not be read as proof that the treatment works equally well for everyone.

The study took place between February and June 2025 at the Rehabilitation Hospital and Sanatorium in Goczałkowice-Zdrój, a lowland health resort in Poland’s Oświęcim Valley that received official health resort status in 2016. Of 238 individuals who initiated and completed the full 21-day program during the study period, 100 met all eligibility criteria and completed both baseline and post-treatment assessments. Ten participants with a BMI of 35 kg/m² or higher were later excluded because their small numbers made it impossible to form meaningful class II and class III obesity groups, leaving a final cohort of 90 people: 18 men and 72 women with a mean age of 69.32 years. Participants were divided into three groups: 21 with normal weight (BMI 18.5–24.9), 41 with overweight (BMI 25.0–29.9), and 28 with class I obesity (BMI 30.0–34.9).

The treatment program reflected routine Polish spa rehabilitation practice. It ran six days a week and included at least three procedures daily, personalized after a pre-treatment clinical assessment. Balneological treatments were central: peloid therapy, applied at 40 °C for 15 minutes, was given to 95.56% of participants, and brine therapy at 38–40 °C for 15 minutes to 75.56%. Vacuum massage was used in 53.33% of participants and was given significantly more often to those who were overweight. These modalities were combined with physiotherapist-supervised exercise sessions targeting joint mobility, muscular endurance, strength, coordination, and balance, as well as health education covering nutrition, physical activity, and substance-use prevention. The most common comorbidity was hypertension, present in 53.33% of participants, followed by hypothyroidism at 23.33% and diabetes mellitus at 13.33%.

Insomnia was measured with the Athens Insomnia Scale, an eight-item questionnaire scored from 0 to 24, where a threshold of six points identifies insomnia with high sensitivity and specificity. Quality of life was assessed with the EQ-5D-5L questionnaire, covering mobility, self-care, usual activities, pain/discomfort, and anxiety/depression, alongside the EuroQol Visual Analog Scale on which participants rate their overall perceived health. At admission, 45.56% of participants met the insomnia threshold. The prevalence climbed across BMI categories, from 38.10% in the normal-weight group to 43.90% in the overweight group and 53.57% in the class I obesity group, though these differences were not statistically significant. Mean AIS scores were roughly 25% higher in the overweight group and 36% higher in the obese group compared with normal-weight participants, again without reaching statistical significance.

After treatment, the overall prevalence of insomnia fell to 37.78%, a statistically significant decrease. The drop was significant in the overweight group, where prevalence fell to 31.71%, but not in the normal-weight group (33.33%) or the class I obesity group (50%). Insomnia severity itself improved significantly within every BMI group. The mean AIS reduction was about 23% in the normal-weight group, roughly 38% in the overweight group, and about 20% in the class I obesity group, with standardized within-group effects that were moderate in the first and third groups and moderate to large in the second. Yet when the researchers compared the changes between groups, the overall effect was small and not statistically significant, and all Bonferroni-adjusted pairwise comparisons produced confidence intervals that included zero.

The quality-of-life results followed a similar pattern. EQ-5D-5L Visual Analog Scale scores rose in all three groups, with mean increases of 13.10 points in the normal-weight group, 12.20 points in the overweight group, and 12.50 points in the obese group, each corresponding to a large standardized within-group effect and relatively precise confidence intervals. The between-group effect, however, was very small and not significant. The EQ-5D-5L index improved significantly in the normal-weight and overweight groups but not in the obese group, and again the between-group differences were not significant. Within the questionnaire’s five dimensions, only pain/discomfort improved significantly across all groups; mobility, self-care, and usual activities were largely unchanged, likely because eligibility for health resort treatment requires participants to be independently mobile and capable of self-care, leaving little room for improvement at baseline.

Multivariable regression models adjusted for age, sex, blood pressure, heart rate, comorbidity status, and BMI group found no significant association between BMI category and changes in insomnia severity or the EQ-5D-5L index. In the model for VAS changes, which was statistically significant overall, the only significant predictor was diastolic blood pressure. Exploratory logistic regression suggested that classical massage, mechanical massage, local cryotherapy, and low-level laser therapy were associated with lower odds of post-treatment insomnia, and low-level laser therapy with higher odds of index improvement, but the authors stress these associations do not establish causation because treatments were individually selected rather than randomly assigned. Notably, vacuum massage, given most often to overweight participants, showed no significant association with any outcome.

The study also used regression-based simulations to explore what would happen if participants had lost weight. A hypothetical 3% reduction in body weight was associated with an estimated 0.229-point increase in the VAS change, and a 3% BMI reduction with a 0.317-point increase, both statistically significant in the models. By contrast, the simulated effects on insomnia severity and the EQ-5D-5L index were negligible. The authors emphasize that these are model-based estimates from observational data and do not demonstrate a causal effect of weight loss; they would need confirmation in studies specifically designed to test weight-management interventions.

Why might sanatorium treatment improve sleep at all? The authors discuss several hypotheses, all of which remain untested in their data. One proposal, drawn from prior work, links balneotherapy’s benefits to thermoregulation: sleep onset is normally preceded by a decline in core body temperature and increased peripheral heat dissipation, and warm-water and peloid treatments raise skin temperature in ways that have been associated with shorter sleep onset latency. Obesity may impair this process because excess adipose tissue acts as a thermal insulator, though the researchers found no corresponding BMI-related difference in insomnia improvement in their cohort. Supervised exercise may also have contributed, through enhanced cutaneous vasodilation, nitric oxide production, and effects on neurotransmitters, hormones, and mental health. Pain reduction offers another plausible pathway, since treatment significantly reduced pain in all groups and pain is closely tied to both sleep and quality of life. The resort environment itself, with legally mandated green space and nighttime quiet hours, may have played a supporting role.

The authors are careful about the limits of their work. Without a non-treated control group, the improvements cannot be attributed with certainty to the treatment itself; time-related changes, regression to the mean, expectancy effects, and the resort’s contextual factors may all have contributed. The sample was small and not based on an a priori power calculation, the strict exclusion criteria limit generalizability, and the post hoc exclusion of participants with BMI of 35 or higher means the findings apply only to people with normal weight, overweight, or class I obesity. Medication use, behavioral factors such as napping and caffeine consumption, and body composition were not assessed, and the absence of follow-up prevents any conclusion about whether the benefits lasted. With those caveats in place, the study’s practical message stands: within this cohort of mostly older adults, the benefits of a 21-day comprehensive health resort program, from fewer insomnia symptoms to better perceived health, appeared broadly similar whether participants were of normal weight, overweight, or living with class I obesity.

Subject of Research: Effects of comprehensive health resort treatment on insomnia and quality of life across BMI categories

Article Title: Insomnia severity and quality of life before and after comprehensive health resort treatment across BMI categories

Article References: Onik, G., Barański, K., & Suszyński, K. (2026). Insomnia severity and quality of life before and after comprehensive health resort treatment across BMI categories. Frontiers in Public Health, 14, Article 1947274. https://doi.org/10.3389/fpubh.2026.1947274

Image Credits: AI Generated

DOI: 10.3389/fpubh.2026.1947274

Keywords: insomnia, obesity, body mass index, health resort treatment, balneotherapy, quality of life, EQ-5D-5L, Athens Insomnia Scale, peloid therapy, observational study, sleep, rehabilitation