Progressive vs. Non-progressive Water-based Aerobic Training on Type 2 Diabetes Control: a Randomized Clinical Trial

This is a randomized clinical trial with the aim to evaluate the effects of two water-based aerobic training programs (walking or running in shallow pool) on type 2 diabetes control. The sample will be composed by 50 individuals with type 2 diabetes, of both sexes, aged between 40 and 70 years, who will be randomized into water-based progressive aerobic training (PAT, n=25) and water-based non-progressive aerobic training (NPAT, n=25). Both trainings will have 12 weeks of duration with 3 weekly sessions (of 50 minutes each). Biochemical, cardiorespiratory fitness, maximum strength, body composition and functional mobility variables, as also quality of life, sleep quality and depressive symptoms will be analyzed before and after the 12 weeks of training.

Water-based aerobic training can provide benefits with important clinical implications for type 2 diabetes (T2D) patients, as the aquatic environment provides some interesting advantages to this population. The lower impact on joints and consequent reduced chance of injury allows considering the aquatic environment favorable to the principle of continuity with progression of physiological stimuli and metabolic benefits.

In T2D individuals, studies have been analyzing the effects of water-based aerobic training in upright position, which have been promoting several results in metabolic parameters of T2D individuals, including benefits in glucose and lipids levels and in cardiorespiratory fitness.

The literature shows distinct exercise effects on glucose control of T2D patients, resulting from different forms of training structuring, with and without progression of training variables. Well-conducted clinical trials prescribing aerobic training according to American Diabetes Association (ADA) recommendations (i.e. structured aerobic training with weekly duration of at least 150 minutes of moderate to vigorous intensity performed in three or more sessions per week) but with minimal or without progression in training load found no HbA1c reductions, whereas some studies that did not meet the recommendations but progressed training volume and/or intensity over time found interesting HbA1c reductions. With these findings, it seems that the optimization of aerobic training benefits on glucose control may not solely depend on a fixed training dosage, but also on the progression of the volume and/or intensity of training.

Due to the associations between T2D with obesity and hypertension, conditions that create difficulties for individuals performing exercise while supporting their own body mass, the different responses arising from the studies investigating progressive and non-progressive aerobic trainings in T2D patients, and with the important facilities that the aquatic environment can promote during physical exercise performance, it becomes interesting to investigate the effects of the application of two aquatic aerobic trainings on T2D treatment, in which similar exercise programs are performed, with one of them having its training variables fixed over time (non-progressive training) and the other with progression in the variables (progressive training). To the present moment, no clinical trial has investigated the comparison between aquatic aerobic training interventions with and without progression in the training variables on glycemic control of T2D individuals, aiming at exploring the role of training progression.

For this purpose, a randomized clinical trial with the aim to evaluate the effects of two water-based aerobic training programs (walking or running in shallow pool) on T2D management will be performed. The sample will be composed by 50 individuals with T2D, of both sexes, aged between 40 and 70 years, who will be randomized into water-based progressive aeroibic training (PAT, n=25) and water-based non-progressive aerobic training (NPAT, n=25). Both trainings will have 12 weeks of duration with 3 weekly sessions (of 50 minutes each). Biochemical, cardiorespiratory fitness, maximum strength, body composition and functional mobility variables, as also quality of life, sleep quality and depressive symptoms will be analyzed before and after the 12 weeks of training.

Eligibility Criteria:
Inclusion Criteria:

* Individuals with type 2 diabetes, of both sexes, aged between 40 and 70 years.
* Be under medical treatment with oral hypoglycemic agents and / or insulin;
* Not be engaged in regular exercise (regular exercise was defined as performing any type of physical training for at least 20 minutes three or more days a week).

Exclusion Criteria:

* Presence of:
* uncontrolled hypertension;
* autonomic neuropathy;
* severe peripheral neuropathy;
* proliferative diabetic retinopathy;
* severe non-proliferative diabetic retinopathy;
* uncompensated heart failure;
* peripheral amputations;
* chronic kidney failure;
* body mass index (BMI)\> 45.0 kg/m2;
* to have some muscle or joint impairment that prevents the performance of physical exercises safely.