Exercise Training and Vitamin D Metabolism

NCT07300332 | Recruiting

• 1 other identifier: UTH_2612_8.10.2025
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

The prevalence of Vitamin D deficiency is significantly higher in adults with overweight/obesity compared to those with normal body mass index (BMI). The "entrapment" of Vitamin D in adipose tissue due to impaired lipolytic stimulation and/or adipose tissue dysfunction has been proposed as the driving mechanism. Exercise training has been proposed as a promising strategy to increase mobilization of Vitamin D from adipose tissue, given its well described role in stimulating lipolysis. Indeed, a recent study revealed that participation in moderate-intensity cardiovascular type exercise over winter can mitigate the decline in 25-hydroxyvitamin D \[25(OH)D\] in adults with overweight/obesity, independent of weight loss. The aim of this study is to investigate the impact of hybrid-type high-intensity interval training over winter on vitamin D metabolism, in adults with overweight/obesity.

Conditions

Obesity & Overweight; Vitamin D

Keywords

overweight; obesity; vitamin D; 25-hydroxyvitamin D; high-intensity interval training

Outcome Measures

Primary Outcomes (7)

• Change in 25-hydroxyvitamin D concentration

  25-OH-VD will be quantitatively determined in serum

  At baseline, 6 weeks and 12 weeks

• Change in plasma Vitamin D binding protein concentration

  Vitamin D binding protein concentration will be determined in plasma

  At baseline, 6 weeks and 12 weeks

• Change in calcium concentration

  Calcium concentration will be determined in serum

  At baseline, 6 weeks and 12 weeks

• Change in albumin concentration

  Albumin concentration will be determined in serum

  At baseline, 6 weeks and 12 weeks

• Change in aspartate aminotransferase (SGOT) concentration

  SGOT concentration will be determined in serum on a Clinical Chemistry analyzer

  At baseline, 6 weeks and 12 weeks

• Change in alanine aminotransferase (SGPT) concentration

  SGPT concentration will be determined in serum on a Clinical Chemistry analyzer

  At baseline, 6 weeks and 12 weeks

• Change in gamma-glutamyl transferase (γ-GT) concentration

  γ-GT concentration will be determined in serum on a Clinical Chemistry analyzer

  At baseline, 6 weeks and 12 weeks

Secondary Outcomes (5)

• Change in reduced glutathione concentration

  At baseline, 6 weeks and 12 weeks

• Change in oxidized glutathione concentration

  At baseline, 6 weeks and 12 weeks

• Change in dietary intake

  At baseline, 6 weeks and 12 weeks

• Change in physical activity level

  At baseline, 6 weeks and 12 weeks

• Change in body composition

  At baseline, 6 weeks and 12 weeks

Study Arms (2)

Exercise group

EXPERIMENTAL

Exercise group will participate in three hybrid-type high-intensity interval training sessions per week over a 12-week period, while receiving a balanced diet

Other: Exercise training

Control group

ACTIVE COMPARATOR

Control group will receive a balanced diet but will not participate in exercise training

Other: Control

Interventions

Exercise training OTHER

Receive a balanced diet and participate in three hybrid-type high-intensity interval training sessions per week over a 12-week period

Exercise group

Control OTHER

Receive a balanced diet but abstain from any type of exercise training

Control group

Eligibility Criteria

• Age: 35 Years - 50 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• BMI = 25-35 kg/m2
• Absence of musculoskeletal injuries
• Absence of chronic health-related complications
• Non-smokers

You may not qualify if:

• Consumption of Vitamin D supplements
• Consumption of anti-inflammatory drugs, statins and/or steroids

Sponsors & Collaborators

• University of Thessaly: lead

Study Sites (1)

Department of Physical Education and Sport Science, University of Thessaly

Trikala, Karyes, 42100, Greece

RECRUITING

MeSH Terms

Conditions

Obesity; Overweight

Interventions

Exercise

Condition Hierarchy (Ancestors)

Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena

Study Officials

• Dimitrios Draganidis, PhD

  University of Thessaly

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Dimitrios Draganidis, PhD

CONTACT

+302431047078; ddraganidis@uth.gr

Ioannis G Fatouros, PhD

CONTACT

2431047047; ifatouros@uth.gr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Study Record Dates

• First Submitted: December 9, 2025
• First Posted: December 23, 2025
• Study Start: November 10, 2025
• Primary Completion: January 31, 2026
• Study Completion (Estimated): July 20, 2026
• Last Updated: May 26, 2026

Record last verified: 2026-05

Locations

GR (1)