Investigation of the Relationship Between Gray and White Matter Volumes, Walking Exercise, and Body Fat Percentage in Adults With a Body Mass Index Above 25

Overview

This study examines the relationship between walking exercise, body fat percentage changes, and brain gray and white matter volumes in overweight and obese adults with headache complaints. Participants with a Body Mass Index (BMI) of 25 or above will be divided into two groups: one receiving a diet program combined with a 12-week walking exercise regimen, and a control group receiving diet alone. Both groups will undergo brain MRI scans and body composition measurements at baseline and after 12 weeks. The study aims to determine whether exercise-induced reductions in body fat percentage have a measurable impact on brain structure, specifically gray and white matter volumes. Blood tests will monitor metabolic markers throughout the intervention. This research may contribute to understanding how different types of exercise affect brain health and inform the development of more effective treatments for obesity-related neurological changes.

Background: Obesity has become a major public health concern over the past 40 years, with increasing evidence linking elevated BMI to numerous physical and mental health problems. Neuroimaging studies demonstrate that obesity negatively affects brain function and structure, particularly within the fronto-mesolimbic circuit. Structural MRI studies have revealed associations between obesity and reduced gray/white matter volumes, altered cortical morphometry, and impaired white matter integrity. Research highlights obesity's impact on cognitive functions including decision-making, inhibition control, learning/memory, and attention. Study Design: This is a 12-week prospective experimental study with a control group design. The study will recruit 22 adults (11 per group) with BMI ≥25 who present with headache complaints to the neurosurgery department between January-March 2024. Inclusion Criteria: Adults aged 19-65 years with headache complaints BMI ≥25 kg/m² Brain MRI performed between 01.01.2024-01.03.2024 Baseline blood tests completed (fasting glucose, lipid profile, liver enzymes, thyroid function, vitamin B12, hemogram, HbA1c) Scheduled for routine 6-month follow-up blood work Willing to undergo follow-up brain MRI at 12 weeks (funded by researchers) Able to attend 6 biweekly nutrition counseling sessions over 12 weeks Able to attend 6 biweekly body composition measurements No diagnosed chronic conditions (hypertension, diabetes) Proficient with smartphone heart rate and step counter applications Exclusion Criteria: Chronic diseases (hypertension, diabetes) Physical disabilities Use of antidepressant medications Regular exercise practitioners History of cerebrovascular disease Epilepsy diagnosis Multiple sclerosis or Alzheimer's disease Conditions affecting brain ventricular volume (e.g., hydrocephalus) Pregnancy or breastfeeding Intervention: Exercise Protocol (Experimental Group): Exercise intensity will be determined using the Karvonen method to establish target heart rate. Walking exercise will be prescribed 5 days per week, with progressive intensity increases from 50% to 70% maximum heart rate over 12 weeks. Session duration will gradually increase from 20 minutes initially to 60 minutes by week 12 to support adaptation and achieve maximum heart rate targets. Heart rate will be monitored every 20 minutes during exercise using smartphone applications. Diet Protocol (Both Groups): Individual energy needs will be calculated using Mifflin-St. Jeor equations based on current weight. Physical activity level (PAL) will be determined, and total energy expenditure calculated. Diet prescriptions will create a 500-750 kcal/day deficit targeting 0.5-1 kg weekly weight loss, with a goal of 5% weight reduction over 12 weeks. Macronutrient distribution will be 50-60% carbohydrates, 15-20% protein, and 25-30% fat. Measurements: Baseline and 12-Week Assessments: Sociodemographic Data: Personal interview form Anthropometrics: Height measured with SECA 216 stadiometer; BMI calculated Body Composition: InBody 370 bioelectrical impedance analysis under standardized conditions (light clothing, barefoot, fasted ≥2 hours, post-void 30 minutes) Blood Samples: Fasting (12 hours) venous blood collected at 09:00 AM to minimize circadian variation. Analysis includes fasting glucose, lipid profile, liver enzymes (ALT, AST, GGT), thyroid function (T3, T4, TSH), vitamin B12, complete blood count, and HbA1c Brain MRI: Performed using 1.5T Siemens Magnetom Avanto scanner with standard head coil. T2-weighted axial images using 3D SPGR sequence (TR=800ms, TE=26ms, FOV=230mm, resolution=192x256, slice thickness=5mm). T1-weighted axial images (FOV=420mm, FOV Phase=81.3%, slice thickness=6mm, TR=170ms, TE=2.38ms)