Effects of a Mediterranean Diet With Cycling and Rowing Exercise on Blood Sugar in Women With Prediabetes

Sponsor
Begüm Yücesoy Güneysu
Study ID
NCT07326891
Status
Enrolling By Invitation

Conditions

  • Prediabetes

Eligibility Criteria

Sex
FEMALE
Age
22 Years - 55 Years
Healthy Volunteers
Not accepted

Interventions

  • Mediterranean Diet — OTHER
    This is a 12-week personalised dietary intervention based on the Mediterranean diet, structured around four daily meals. It emphasises a high intake of vegetables, fruits, whole grains, legumes, nuts and olive oil, as well as moderate consumption of fish and poultry, and a low intake of red meat, processed foods and sweets. Participants receive individual counselling sessions with a dietitian every two weeks and are required to keep a daily food diary to monitor adherence and provide feedback.
  • Supervised Sequential Exercise — BEHAVIORAL
    An 8-week, supervised, sequential aerobic exercise program. Participants attend three sessions per week. The first 4 weeks consist of cycling ergometer sessions, followed by 4 weeks of rowing ergometer sessions. Exercise intensity is personalized using Heart Rate Reserve (HRR) based on directly measured maximum heart rate from a baseline cardiopulmonary exercise test. Sessions are supervised by an exercise physiologist.

Study Details

The goal of this clinical trial is to learn how a Mediterranean-style diet, with and without added exercise, affects blood sugar control in women with prediabetes. Prediabetes means blood sugar levels are higher than normal but not yet type 2 diabetes. Healthy eating and regular physical activity can help prevent diabetes. The investigators aim to answer two main questions: 1. Does adding a supervised program of cycling and rowing exercises to the diet lead to better blood sugar control than the diet alone? 2. Do women who recently returned to normal blood sugar levels respond differently to the exercise program than those who currently have high blood sugar? Participants will be placed into one of three groups based on current blood sugar levels and medical fitness for exercise: * Group 1 (Diet only): Will follow a Mediterranean eating plan for 12 weeks. * Group 2 (Diet + Exercise, Current High Blood Sugar): Will follow the same diet and also do supervised exercise (cycling, then rowing) three times a week for 8 weeks. * Group 3 (Diet + Exercise, Recent Normal Blood Sugar): Will follow the same diet and exercise program as Group 2. These women had prediabetes in the past year but now have normal blood sugar levels. All participants will follow the study protocol for 12 weeks, which includes the following key components: * Dietary Intervention: Adherence to a Mediterranean-style eating plan, which emphasizes high intake of vegetables, fruits, whole grains, legumes, olive oil, and fish. * Continuous Glucose Monitoring: Wearing a continuous glucose monitoring (CGM) device-a small, minimally invasive sensor placed on the upper arm-during multiple 10-day periods. This device tracks interstitial glucose levels throughout the day and night to assess daily glucose patterns. * Blood Sampling and Analysis: Providing fasting blood samples for the measurement of glycemic and metabolic health markers. These include fasting plasma glucose, hemoglobin A1c (HbA1c), fasting insulin, and 2-hour oral glucose tolerance test (OGTT) results. * Anthropometric Assessments: Undergoing standardized measurements of height, body weight, body fat percentage (via bioelectrical impedance), waist circumference, and Body Mass Index (BMI) at scheduled intervals. * Questionnaires: Completing validated surveys to assess habitual dietary intake, sleep quality and duration, and levels of physical activity. Investigators will compare changes in blood sugar control and other health measures from the start to the end of the 12-week study among the three groups.

Key Dates

First listed
Jan 8, 2026
Start date
Dec 15, 2025
Status verified
Dec 2025
Primary completion
Jul 31, 2026
Completion
Dec 31, 2026

Study Design

Enrollment
30 participants (estimated)
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT

Arms

  • Active Comparator: Control Group
    Women with medically documented prediabetes who are not eligible for the supervised exercise program for medical reasons. This arm serves as the primary comparison group and represents standard care. Participants will follow a 12-week individualized Mediterranean diet intervention emphasizing high intake of vegetables, fruits, whole grains, legumes, nuts, and olive oil; moderate consumption of fish and poultry; and low intake of red meat, processed foods, and sweets. Dietary counseling will be provided by a dietitian, and participants will complete food diaries. All participants will undergo the same scheduled assessments as the intervention arms, including blood tests, anthropometric measurements, questionnaires, and continuous glucose monitoring (CGM).
  • Experimental: Active Prediabetes Exercise Group
    Women with active prediabetes who are medically eligible for exercise will participate in a 12-week intervention including a Mediterranean-style diet throughout the study and a supervised 8-week sequential exercise program between Weeks 3 and 10. The exercise program will consist of cycling ergometer training during Weeks 3-6 and rowing ergometer training during Weeks 7-10. Participants will complete three supervised sessions per week, each lasting approximately 51 minutes. Exercise intensity will be individualized using the Heart Rate Reserve (HRR) method, based on resting heart rate and maximal heart rate measured by a maximal Bruce protocol test. Each session will include a warm-up at 40% HRR, alternating intervals at 50% and 60% HRR with short recovery periods, and a cool-down at 40% HRR. Heart rate will be continuously monitored using a Polar H10 chest strap.
  • Experimental: Remission Prediabetes Exercise Group
    Participants in this arm are women with a documented diagnosis of prediabetes within the past year who are normoglycemic at screening according to American Diabetes Association (ADA) criteria and are medically eligible to participate in exercise. These participants will receive the same 12-week Mediterranean diet program and the same supervised 8-week sequential exercise intervention (cycling followed by rowing) as the active prediabetes exercise group.

Primary Outcome Measure

Change in Fasting Plasma Glucose (FPG) [ Time Frame: Baseline (week 0) and the end of the 12 weeks program (week 13) ]

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