Mitochondrial Metabolism and Oxidative Stress in Function of the Physical Exercise and Nutritional Counseling in T2DM

NCT ID: NCT07251504

Last Updated: 2025-11-26

Basic Information

• Recruitment Status: ACTIVE_NOT_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 146 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-03-10
• Study Completion Date: 2025-12-31

Brief Summary

The goal of this randomized controlled trial is to learn about the effects of different aerobic modalities (moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT)) and diet on mitochondrial properties and oxidative stress in patients with type 2 diabetes (T2D). It will also learn about the different effects of these interventions in men and women. The main questions it aims to answer are:

• What is the isolated and combined effect of these exercise modalities and diet? Is there a superior approach for mitochondrial metabolism and oxidative stress in patients with T2D?
• Is there a sex-specific best combination choice for these different interventions?
• Is there any relation between exercise and diet-induced changes in mitochondrial properties and oxidative stress and other health-related outcomes such as body composition or insulin sensitivity?

To answer these questions, researchers designed a two-factor study. One factor was exercise, which had three levels (MICT, HIIT, and the inactive (INACT) condition). The second factor was diet, with two levels (Diet (D) and no diet (ND)). Hence, participants were randomly allocated into 6 groups: INACT-ND, INACT-D, MICT-ND, MICT-D, HIIT-ND, and HIIT-D.

Participants did:

• Underwent a 12-week intervention within the condition of his/her group
• Visit the research group facilities three times per week if in an exercise group or once every two weeks if in a diet group.

Detailed Description

This is a randomized controlled trial conducted in the Province of Cádiz (Spain). A total of 146 participants were enrolled in the study and underwent baseline and post-intervention determinations of the study outcomes. Just after the baseline determination, participants were randomly allocated to one of the aforementioned study groups. The randomization process was stratified by sex, which means that approximately 50% of participants in each group were women. All participants received detailed written and verbal information about the study objectives, procedures, benefits, and potential risks before providing written informed consent. This study adhered to the principles of the Declaration of Helsinki and was approved by the Provincial Research Ethics Committee of Cádiz and the Coordinating Committee of Biomedical Research Ethics of Andalucía (registration number 92.21; PEIBA number 1026-N-21; internal codes SICEIA-2025-001870 and SICEIA-2025-000778).

At both baseline and post-intervention, participants were scheduled in the morning following an overnight fast of 8-10 hours. They were instructed to maintain their usual lifestyle, abstain from alcohol and caffeine for 24 hours, and avoid strenuous physical activity for 72 hours prior to testing. Procedures included body composition assessment through electrical bioimpedance, a vastus lateralis muscle biopsy, fasting blood collection, and an oral glucose tolerance test (OGTT) by ingesting 75 grams of glucose and blood draws at 30, 60, 90, 120, 150, and 180 minutes post-ingestion. The same protocol was repeated after the 12-week intervention, with exercise groups completing their final training session at least 72 hours before the post-intervention assessments.

Conditions

Diabetes Mellitus, Type 2

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

ND-INACT

Participants who did not receive either nutritional intervention or exercise program. They were instructed to maintain their normal life habits regarding physical activity and diet.

Group Type: NO_INTERVENTION

No interventions assigned to this group

Moderate-intensity continuous training (ND-MICT)

Participants who did not receive nutritional intervention but were enrolled in a moderate-intensity continuous training exercise program.

Group Type: ACTIVE_COMPARATOR

The Moderate-Intensity Continuous Training (MICT)

Intervention Type: OTHER

Participants assigned to the MICT completed 3 weekly sessions, with 1-2 days of rest between sessions, on a cycle ergometer for 12 weeks.

MICT consisted of 50 minutes of continuous pedaling at an intensity approximately 10 % above the lactate threshold, with a cadence between 60-80 rpm. Training load (TL) was increased by 10% if these two conditions were met: 1) no increase of at least 2 beats of heart rate from minute 20 to minute 40 of the training session, and 2) lactate levels below 2 mmol/L in minute 48 of the session. The TL for the first session was determined by an adjustment test consisting of an incremental test with five consecutive 10-minute phases at a constant cadence (60-80 RPM) from 90% to 130% of the ventilatory threshold power, calculated from previously performed FatOx test data, with 10% increments in each step. TL was determined by the phase in which HR increased by ≥ 3 beats between phases and blood lactate levels increased by ≥ 1 mmol/L from the previous phase.

High-intensity interval training (ND-HIIT)

Participants who did not receive nutritional intervention but were enrolled in a high-intensity interval training exercise program.

Group Type: ACTIVE_COMPARATOR

The High-Intensity Interval Training (HIIT)

Intervention Type: OTHER

Participants assigned to the HIIT completed 3 weekly sessions, with 1-2 days of rest between sessions, on a cycle ergometer for 12 weeks.

The training load (TL) was determined from an incremental test until volitional exhaustion with one-minute work intervals (from 85% to 165% of maximal power output from a previously performed VO2max test [Wmax] and with 10% increments) separated by 1.5-minute rest periods (at 20% Wmax).

The program consisted of a 3 minutes warm-up with the first 2 minutes at 20% and last minute at 40% of the TL, followed by 10 series of 1 min duration at 90% of TL, with 1 minute of rest between sets at 40% of TL and ending with 2 minutes of cool-down at 20% of TL (estimated total time of the session: 25 minutes). A 5% increase in workload was applied when, for two consecutive sessions, the first three intervals failed to exceed 85%, and the last five did not reach 90% of maximal HR. Participants were asked to maintain a cadence above 80RPM.

Nutritional intervention (D-INACT)

Participants who received nutritional intervention but not an exercise program.

Group Type: ACTIVE_COMPARATOR

Nutritional intervention

Intervention Type: BEHAVIORAL

The nutritional intervention was conducted through biweekly (± 3 days) in-person consultations with a nutritionist or dietitian over an entire period of 12 weeks. Firstly, the patient's diet was analyzed. Then, participants were guided to follow a Mediterranean pattern-based and mildly calorie-restricted diet, with the primary goal of achieving a 5 % reduction in body weight and reducing blood glucose levels. Meal plans were created using Nutrium® software , personalized to each participant's lifestyle and food preferences, and reviewed at each biweekly consultation. The dietary plan included at least 4 meals per day, ensuring a well-distributed intake of carbohydrates, a balanced distribution of macro- and micronutrients, and the inclusion of foods rich in prebiotics and probiotics. Moreover, some suggestions about the combination of foods and culinary techniques were provided. Only one session through the intervention was allowed to be attended telephonically.

Nutritional Intervention Moderate-Intensity continuous training (D-MICT)

Participants who received nutritional intervention and were enrolled in a moderate-intensity continuous training exercise program.

Group Type: EXPERIMENTAL

Nutritional intervention

Intervention Type: BEHAVIORAL

The nutritional intervention was conducted through biweekly (± 3 days) in-person consultations with a nutritionist or dietitian over an entire period of 12 weeks. Firstly, the patient's diet was analyzed. Then, participants were guided to follow a Mediterranean pattern-based and mildly calorie-restricted diet, with the primary goal of achieving a 5 % reduction in body weight and reducing blood glucose levels. Meal plans were created using Nutrium® software , personalized to each participant's lifestyle and food preferences, and reviewed at each biweekly consultation. The dietary plan included at least 4 meals per day, ensuring a well-distributed intake of carbohydrates, a balanced distribution of macro- and micronutrients, and the inclusion of foods rich in prebiotics and probiotics. Moreover, some suggestions about the combination of foods and culinary techniques were provided. Only one session through the intervention was allowed to be attended telephonically.

The Moderate-Intensity Continuous Training (MICT)

Intervention Type: OTHER

Participants assigned to the MICT completed 3 weekly sessions, with 1-2 days of rest between sessions, on a cycle ergometer for 12 weeks.

MICT consisted of 50 minutes of continuous pedaling at an intensity approximately 10 % above the lactate threshold, with a cadence between 60-80 rpm. Training load (TL) was increased by 10% if these two conditions were met: 1) no increase of at least 2 beats of heart rate from minute 20 to minute 40 of the training session, and 2) lactate levels below 2 mmol/L in minute 48 of the session. The TL for the first session was determined by an adjustment test consisting of an incremental test with five consecutive 10-minute phases at a constant cadence (60-80 RPM) from 90% to 130% of the ventilatory threshold power, calculated from previously performed FatOx test data, with 10% increments in each step. TL was determined by the phase in which HR increased by ≥ 3 beats between phases and blood lactate levels increased by ≥ 1 mmol/L from the previous phase.

Nutritional Intervention High-intensity interval training (D-HIIT)

Participants who received nutritional intervention and were enrolled in a high-intensity interval training exercise program.

Group Type: EXPERIMENTAL

Nutritional intervention

Intervention Type: BEHAVIORAL

The nutritional intervention was conducted through biweekly (± 3 days) in-person consultations with a nutritionist or dietitian over an entire period of 12 weeks. Firstly, the patient's diet was analyzed. Then, participants were guided to follow a Mediterranean pattern-based and mildly calorie-restricted diet, with the primary goal of achieving a 5 % reduction in body weight and reducing blood glucose levels. Meal plans were created using Nutrium® software , personalized to each participant's lifestyle and food preferences, and reviewed at each biweekly consultation. The dietary plan included at least 4 meals per day, ensuring a well-distributed intake of carbohydrates, a balanced distribution of macro- and micronutrients, and the inclusion of foods rich in prebiotics and probiotics. Moreover, some suggestions about the combination of foods and culinary techniques were provided. Only one session through the intervention was allowed to be attended telephonically.

The High-Intensity Interval Training (HIIT)

Intervention Type: OTHER

Participants assigned to the HIIT completed 3 weekly sessions, with 1-2 days of rest between sessions, on a cycle ergometer for 12 weeks.

The training load (TL) was determined from an incremental test until volitional exhaustion with one-minute work intervals (from 85% to 165% of maximal power output from a previously performed VO2max test [Wmax] and with 10% increments) separated by 1.5-minute rest periods (at 20% Wmax).

The program consisted of a 3 minutes warm-up with the first 2 minutes at 20% and last minute at 40% of the TL, followed by 10 series of 1 min duration at 90% of TL, with 1 minute of rest between sets at 40% of TL and ending with 2 minutes of cool-down at 20% of TL (estimated total time of the session: 25 minutes). A 5% increase in workload was applied when, for two consecutive sessions, the first three intervals failed to exceed 85%, and the last five did not reach 90% of maximal HR. Participants were asked to maintain a cadence above 80RPM.

Interventions

Nutritional intervention

The nutritional intervention was conducted through biweekly (± 3 days) in-person consultations with a nutritionist or dietitian over an entire period of 12 weeks. Firstly, the patient's diet was analyzed. Then, participants were guided to follow a Mediterranean pattern-based and mildly calorie-restricted diet, with the primary goal of achieving a 5 % reduction in body weight and reducing blood glucose levels. Meal plans were created using Nutrium® software , personalized to each participant's lifestyle and food preferences, and reviewed at each biweekly consultation. The dietary plan included at least 4 meals per day, ensuring a well-distributed intake of carbohydrates, a balanced distribution of macro- and micronutrients, and the inclusion of foods rich in prebiotics and probiotics. Moreover, some suggestions about the combination of foods and culinary techniques were provided. Only one session through the intervention was allowed to be attended telephonically.

Intervention Type: BEHAVIORAL

The High-Intensity Interval Training (HIIT)

Participants assigned to the HIIT completed 3 weekly sessions, with 1-2 days of rest between sessions, on a cycle ergometer for 12 weeks.

The training load (TL) was determined from an incremental test until volitional exhaustion with one-minute work intervals (from 85% to 165% of maximal power output from a previously performed VO2max test [Wmax] and with 10% increments) separated by 1.5-minute rest periods (at 20% Wmax).

The program consisted of a 3 minutes warm-up with the first 2 minutes at 20% and last minute at 40% of the TL, followed by 10 series of 1 min duration at 90% of TL, with 1 minute of rest between sets at 40% of TL and ending with 2 minutes of cool-down at 20% of TL (estimated total time of the session: 25 minutes). A 5% increase in workload was applied when, for two consecutive sessions, the first three intervals failed to exceed 85%, and the last five did not reach 90% of maximal HR. Participants were asked to maintain a cadence above 80RPM.

Intervention Type: OTHER

The Moderate-Intensity Continuous Training (MICT)

Participants assigned to the MICT completed 3 weekly sessions, with 1-2 days of rest between sessions, on a cycle ergometer for 12 weeks.

MICT consisted of 50 minutes of continuous pedaling at an intensity approximately 10 % above the lactate threshold, with a cadence between 60-80 rpm. Training load (TL) was increased by 10% if these two conditions were met: 1) no increase of at least 2 beats of heart rate from minute 20 to minute 40 of the training session, and 2) lactate levels below 2 mmol/L in minute 48 of the session. The TL for the first session was determined by an adjustment test consisting of an incremental test with five consecutive 10-minute phases at a constant cadence (60-80 RPM) from 90% to 130% of the ventilatory threshold power, calculated from previously performed FatOx test data, with 10% increments in each step. TL was determined by the phase in which HR increased by ≥ 3 beats between phases and blood lactate levels increased by ≥ 1 mmol/L from the previous phase.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Diagnosis of T2D or prediabetes (glycated hemoglobin ≥ 5.7%)
• No history of substance abuse (tobacco, alcohol, or other drugs).
• Body mass index >25 kg/m², maintaining the habitual dietary patterns with stable body weight for at the least 6 months
• Stable physical activity and medication regimen for at least 6 months
• Not insulin-dependent
• Absence of injury, disease, disability, or other known medical condition which could affect the ability to successfully participate in physical exercise tests
• Absence of tumours and cancer disease
• Absence of other pathologies that could affect the study outcomes.
• Not under medication regimen that could affect the study outcomes.
• Being able to understand a communication in Spanish or English.
• Not pregnant

Exclusion Criteria

• Failure to attend more than 2 consecutive or a total of 4 sessions of nutritional intervention.
• Failure to attend more than 4 consecutive or a total of 6 sessions of physical training.
• Serious injury
• Voluntary withdrawal
• Increased dose of diabetes medication

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Instituto de investigación e innovación biomédica de Cádiz

OTHER

Sponsor Role: collaborator

University of Cadiz

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Cristina Casals Vázquez, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Cádiz

Miguel Efrén Jiménez Romero, MD

Role: PRINCIPAL_INVESTIGATOR

Hospital de la Línea de la Concepción

Locations

Science of Education Faculty

Puerto Real, Cádiz, Spain

Countries

Spain

Other Identifiers

PP11-007-2023

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

MITOX

Identifier Type: -

Identifier Source: org_study_id