The purpose of this trial is to pragmatically investigate whether participation of people with diabetes and prediabetes in an Exercise and Lifestyle Education Program (i.e., exercise and education classes) results in better functional capacity, disease-related knowledge and behavior, and cardiometabolic health parameters when compared to Exercise Program (i.e., exercise class only). In addition, the effects of these interventions will be evaluated on other outcomes: program adherence, satisfaction with the program, quality of life, diet quality, depression, and morbidity associated with diabetes in the 6-month follow-up.

The design is a multicenter, double-blind (outcomes assessors and data analysts), randomized and controlled trial with 2 parallel arms: Exercise Program (Ex) and Exercise and Lifestyle Education Program (ExLE). The sample size was calculated considering the ISWT distance as the primary outcome and based on a previous study that tested the effects of a comprehensive cardiac rehabilitation program on the same primary outcome in coronary patients. The calculation was made using R Software version 3.4.3 and considering the following parameters: moderate effect size (d = 0.20), the statistical power of 80%, an alpha level of 5%, a one-sided test, two arms, and three measurements. A total of 200 participants (100 per program) was required. Assuming a 20% attrition rate based on previous studies using educational intervention in Cardiac Rehabilitation patients, it will take 120 participants in each program to sign the consent form to have 200 participants complete the study.

Adults with diabetes and prediabetes will be recruited from public and private health services in two Brazilian cities (Belo Horizonte and Juiz de Fora). Volunteers will be allocated to participate in the program to which they were randomized and be invited for follow-up and reassessment after 6 months of program completion. In this sense, three assessments will be performed: pre-intervention (baseline), post-intervention, and 6 months post-program completion.

The baseline assessment will comprise an interview to obtain their clinical characteristics and sociodemographic data, medical history, vital signs measurement, electrocardiographic monitoring, and measurement of primary, secondary, and tertiary outcomes (other pre-specified outcome measures) through questionnaires and specific tests.

The number of patients approached, the date, and the reasons for inclusion/exclusion will be registered. With informed written consent from the patient, potentially eligible participants will be scheduled to come on-site to complete the baseline assessment. Eligible participants will be randomized to one of the 2 programs (Ex or ExLE). The generation of the randomized allocation sequence will be performed by the project coordinator using the software available on the website www.randomization.com. To ensure allocation concealment, the local research coordinators have the allocation sequence in a password-protected file. They will only provide randomization information to the research team member once it is confirmed the participant is eligible. Due to the nature of the intervention, participants and the research team members cannot be blind to the treatment allocated. However, an independent research member blinded to the group allocation will perform database management and analyses.

The programs (Ex and ExLE) will be delivered on-site or remotely based on internet access and technology literacy screening. Participants who attend these two conditions can choose the delivery format by which they would like to receive the program interventions. For those with no internet access and/or technology literacy, the delivery format of the program interventions will be on-site.

The 12-week exercise intervention consists of at least 150 min of aerobic exercise per week and 2 to 3 muscle-strengthening sessions per week from the 4th week of the intervention. The exercise sessions were structured in exercise sessions (on-site delivery) or exercise plans (remote delivery) as follows: warm-up (stretching exercises and slow walking), aerobic exercise (moderate-to-vigorous intensity walking according to the Borg rating of perceived exertion exercise scale modified), muscle-strengthening exercises (localized muscle endurance exercises that encompass the major muscle groups) and cool down (slow walking and stretching exercises). In the on-site delivery, participants will attend eighteen supervised exercise sessions and receive counseling for unsupervised physical exercise to accumulate at least 150 min/week. They should record their weekly exercise routine in an exercise diary. In the remote delivery, participants will access weekly exercise plans on the Ex program website, and only this program's participants will have access to this website link. They will also receive weekly follow-up text messages via WhatsApp with standardized reminders about exercise goals and the importance of keeping track of their exercise and reporting the exercise sessions in the exercise diary.

In addition to the exercise intervention, participants randomized to the ExLE program will receive a 12-week educational intervention developed based on the Diabetes CollegeTM curriculum (https://www.diabetescollege.ca), translated and culturally adapted for Brazilians living with diabetes and prediabetes. In the on-site delivery, participants will attend eighteen education classes based on the five pillars of Diabetes CollegeTM (treat diabetes, get active, eat healthy, feel well, and take control) and receive a printed version of the Patient Guide (A Guide to Help You Live and Thrive with Diabetes, containing 298 pages and 17 chapters organized into five sections). In the remote delivery, participants will access their weekly lesson plans on the ExLE program website, and only this program's participants will have access to this website link. The educational content consists of the following materials: (1) eighteen video lessons recorded by the research team based on the five pillars of Diabetes CollegeTM, lasting approximately 20 min; (2) twelve videos related to the topics of the week (THRiVE, i.e., videos that integrate principles of chronic disease management and behavior changes to help patients to develop self-management skills through goal setting and action planning); and (3) an printed version of the Patient Guide. In addition, as part of remote delivery, participants will receive weekly WhatsApp text messages from the research team to remind them about the materials in their lesson plan and the importance of keeping track of access to educational content and reporting it in the study diary.

All participants will be invited to the follow-up after the program's completion and the post-intervention assessment.

During the 6-month follow-up, participants will be instructed to record their Diabetes-related morbidity information on the standardized sheet developed by the research team. Research team members will make monthly phone calls to participants to remind them to perform this register properly. Besides that, to minimize dropouts to follow-up, the research team members will send email and phone reminders for patients about to come on-site to the 6-month follow-up assessment post-intervention.

Inclusion Criteria:

• Adult (> 18 years old);
• Self-reported current history of prediabetes or Diabetes Mellitus (type 1 or type 2);
• No cognitive limitation (score ≥ 4 in the six-item screener);
• No vision limitations for reading;
• Literate;
• Written physician permission for exercising;
• No confirmed diagnosis of cardiovascular diseases such as unstable coronary artery disease (CAD), heart failure; use of a pacemaker and/or implantable cardioverter-defibrillator (ICD), intermittent claudication; no recent cardiovascular event or cardiac surgery (≤ 6 months);
• Participants not currently enrolled in a structured physical exercise program that follows diabetes guidelines.

Exclusion Criteria:

• Clinical decompensation that contraindicates the performance of physical exercises;
• Physical and/or mental limitations that will prevent the participant from physically exercising and/or understanding educational content;
• Complex ventricular arrhythmias (i.e., atrial flutter or atrial fibrillation, multiple atrial or ventricular ectopy, and atrioventricular or ventricular block).