Exercise Dose-response for Diabetes in the Elderly

One-center randomized, three-arm, parallel, superiority, controlled trial in 132 elderly outpatients with type 2 diabetes. Two different combined exercise training doses (300min/week vs 150min/week) will be compared against usual care. The entire study length will last 24 weeks, and assessments will be conducted at baseline, previously to the group allocation, at 12 weeks and at 24 weeks just after the treatments' end. The study's primary outcome is the glycated hemoglobin level at 24 weeks. Secondary outcomes of clinical relevance to type 2 diabetes and elderlies will also be acquired.

This study is a randomized controlled trial, three-arm parallel-group. The first aim is to evaluate the efficacy of a supervised and structured combined exercise training program in HbA1c levels at 24 weeks. Secondary outcomes measurements of clinical relevance for type 2 diabetes and elderly patients are included at 12 and 24 weeks.

The investigators will enroll 132 elderlies divided into three experimental groups, randomized in a ratio of 1:1 (44 patients per group). The treatments arms comprises structured supervised combined exercise training programs, three times a week, lasting 24 weeks of duration. The G150 group will exercise 150 min per week of aerobic and strength training (50 min per session, 25 min for each modality) and the G300 group will exercise twice the volume in the same G150's intensity, and week frequency (100 min per session, 50 min for each modality). No intervention will be offered to the control group (i.e., they will continue their usual care). Treatments arms will progress on training load tailored by their maximal heart rate percentage for aerobic training and maximal repetitions for strength training.

The sample size was calculated considering a between-group mean difference of 0.45%, with standard deviation of 0.7% in HbA1c levels, for an 80% of statistical power and 5% of type 1 error, in a superiority hypothesis design.

In detail, the primary outcome is the HbA1c level at 24 weeks, an secondary outcomes are: HbA1c levels at 12 weeks; office blood pressure assessed through a digital sphygmomanometer at 12 and 24 weeks; lipid profile (total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides) at 24 weeks; endothelial function assessed by flow-mediated dilation at 12 and 24 weeks; intima-media thickness at 24 weeks; physical fitness assessed by maximal oxygen uptake and maximal muscle strength at 24 weeks; body composition assessed by dual x ray absorptiometry at 24 weeks; quality of life and geriatric depressive symptoms assessed by questionnaires at 24 weeks.

The investigators hypothesized that the G300 will greater improve the 24-week HbA1c levels and secondary outcomes against the G150 and the control group. The present study was designed and will be conducted by a multidisciplinary staff, and follows ethical and methodological standards for randomized clinical trials. As for empirical evidence provision, it is expected to highlight the efficacy of the non-pharmacological treatment for type 2 diabetes in the elderly patients.

Eligibility Criteria:
Inclusion Criteria:

* Previous diagnosis of type 2 diabetes mellitus by HbA1c (\> 6.5%) or capillary casual glycemia (\> 126 mg/dL), oral glucose tolerance test or hypoglycemic drug use;
* HbA1c ≥ 7.5%;
* Verified ability to exercise;
* Physically inactive or regularly exercising for at least once a week.

Exclusion Criteria:

* HbA1c ≤ 12%;
* Severe cardiovascular disease (class III or IV heart failure, uncontrolled arrhythmia, unstable angina, or use of implantable cardioverter defibrillator);
* Major cardiovascular events 1 year previously to the enrollment (non-fatal myocardial infarction, coronary artery bypass surgery, cardiac catheterization, deep vein thrombosis, hospitalization or other severe health-related event);
* Chronic renal disease requesting dialysis;
* Severe macular injury (retinopathy) that disables patients to enroll an exercise program;
* Severe cognitive impairment (dementia) that disables patients to enroll an exercise program;
* Deafness that disables patients to enroll an exercise program;
* Blindness that disables patients to enroll an exercise program;
* Progressive neurological disorders (Parkinson, multiple sclerosis, etc.) that disables patients to enroll an exercise program;
* Osteoarticular or muscular injuries or another health conditions which generate inability to carry on the interventions;
* Plans of moving to another city during the study;
* Living together with another person enrolled in the study;
* A medical report indicating exercise contraindication based on a cardiopulmonary exercise testing;
* Inability or refusal to give written consent.