Body-Based and Mind-Based Regulation in Overweight and Obese Women

Overweight and obesity are associated not only with metabolic and physical health problems but also with changes in autonomic nervous system regulation, emotional eating, and psychological well-being. Reduced heart rate variability may reflect impaired cardiac vagal regulation and may be related to stress-related and emotion-related eating behaviors. Regulation-based approaches that target either body-to-mind or mind-to-body pathways may provide supportive strategies for improving autonomic and emotional regulation in women with overweight or obesity.

This study is designed as a two-arm, parallel-group, evaluator-blinded randomized trial. The study population will consist of women aged 18 to 60 years with overweight or obesity who apply to the Exercise and Obesity Unit of the Faculty of Physiotherapy and Rehabilitation, Pamukkale University. Participants will be randomized in a 1:1 ratio using BMI-category-stratified block randomization based on a computer-generated allocation sequence prepared by a researcher who is not involved in outcome assessment or intervention delivery. Allocation will be concealed until the baseline assessment is completed. The evaluator who performs baseline and post-intervention assessments will remain blinded to group allocation.

The Body-Based Regulation Group will receive an 8-week structured program delivered face-to-face by a physiotherapist. The program will include breathing awareness, body-awareness-based yoga practices, non-invasive manual auricular stimulation, and restorative relaxation. Sessions will be conducted twice weekly for 8 weeks, with each session lasting approximately 60 minutes. This intervention is intended to support autonomic and cardiac vagal regulation through body-based mechanisms.

The Mind-Based Regulation Group will receive an 8-week structured psychoeducation and cognitive-emotional awareness program. The program will focus on recognizing the relationships among stress, emotional states, automatic thoughts, and eating behavior; identifying triggers for emotional eating; developing more balanced cognitive responses; and creating alternative behavioral strategies for eating urges. Face-to-face structured sessions will be conducted in weeks 1, 4, and 8. In the remaining weeks, participants will receive standardized digital content and study forms and will attend short online meetings. The weekly module duration will be approximately 30 to 45 minutes. This intervention will not include yoga, breathing exercises, relaxation exercises, or other body-based practices.

Assessments will be conducted at baseline and after the 8-week intervention. Heart rate variability will be the primary physiological outcome. RR interval data will be recorded using a Polar H10 chest strap after a 10-minute quiet adaptation period, followed by a 5-minute resting recording. RMSSD will be the primary HRV parameter. If required according to distributional characteristics, RMSSD values will be analyzed after natural logarithmic transformation as lnRMSSD. Secondary HRV parameters will include HF, LF/HF, SDNN, and mean heart rate.

Patient-reported outcomes will include emotional eating, eating behavior, self-compassion, and mindfulness. Anthropometric measurements and body composition will be recorded as exploratory and descriptive outcomes. Adherence to the intervention, completion of home/module-related activities, and possible adverse events will also be monitored throughout the study.

The primary analysis will compare post-intervention RMSSD or lnRMSSD values between groups using an analysis of covariance model adjusted for baseline values. Secondary outcomes will be analyzed using similar baseline-adjusted models where appropriate. The study is planned to include 30 participants in total, with 15 participants in each group.

Inclusion criteria

• Female participants.
• Age between 18 and 60 years.
• Body mass index (BMI) between 27.0 and 39.9 kg/m².
• No regular participation in yoga, meditation, breathing exercises, structured relaxation programs, or similar mind-body practices within the previous 3 months.
• No initiation of a structured weight-loss program within the previous 3 months.
• Able to attend weekly intervention sessions, modules, and study assessments.
• Willing to refrain from starting any new exercise, yoga, meditation, diet, or weight-loss program during the study.
• Able and willing to provide written informed consent.

Exclusion criteria

• BMI ≥40 kg/m².
• Uncontrolled hypertension or severe cardiovascular disease.
• Cardiac arrhythmia, pacemaker, or other cardiac conditions that may affect heart rate variability (HRV).
• Regular use of beta-blockers, antiarrhythmic agents, or other medications that substantially affect HRV (including medications affecting heart rate/rhythm, anticholinergic drugs, tricyclic antidepressants, and stimulant/sympathomimetic medications).
• Neurological disease.
• Uncontrolled thyroid disease or uncontrolled metabolic/endocrine disorders.
• Pregnancy or breastfeeding.
• History of bariatric surgery.
• Initiation of weight-loss medication or GLP-1 receptor agonist therapy within the previous 6 months.
• Current or clinically diagnosed anorexia nervosa, bulimia nervosa, binge eating disorder, or other eating disorders requiring active treatment (emotional eating alone is not an exclusion criterion).
• Psychological or psychiatric conditions that would interfere with safe participation.
• Diagnosed obstructive sleep apnea or untreated severe sleep disorders.
• Regular tobacco or nicotine product use within the previous 3 months.
• Musculoskeletal conditions preventing participation in the intervention.
• Cardiopulmonary or orthopedic limitations that make exercise unsafe.