In diabetic individuals, changes in ventilatory muscle strength and lung function have been demonstrated over the years. The onset and progression of chronic complications in diabetes should be avoided by reaching glycated hemoglobin (HbA1c) levels below 7%. The control of glycemia through the measurement of HbA1c is fundamental to avoid complications. The inspiratory muscle training has been used in several clinical situations, and may be an alternative for individuals with type 2 diabetes mellitus who have difficulties performing conventional exercises. The long-term effect of inspiratory muscle training on glycemic control has not been tested yet. The aim of this study is to evaluate the effects of inspiratory muscle training on glycemic control in individuals with type 2 diabetes.

An acute high intensity inspiratory muscle exercise session was able to reduce glycemic levels (24%) similarly to an aerobic exercise session (25%) in subjects with type 2 diabetes, demonstrating that this type of exercise inspiratory muscle may have great potential in improving glycemic control.The present study will investigate if training of the inspiratory musculature for 8 and 12 weeks is capable of improving glycated hemoglobin, glucose and inspiratory muscle strength in individuals with type 2 diabetes. In addition, this study will evaluate the effect of inspiratory muscle training, with moderate loading of 30% of the MIP, on volumes and capacities lung in patients with type 2 diabetes. The subjects with type 2 diabetes will be recruited from the ambulatory of the Hospital de Clinicas de Porto Alegre and through newspaper advertisements.

Patients will be submitted to a general evaluation, including clinical history, physical examination, laboratory evaluation and application of the international physical activity questionnaire. Subsequently, individuals will perform assessments of lung functions (lung function assessment, ventilatory muscle strength test, inspiratory muscle strength test) and autonomic assessment (Ewing's tests). Patients will be randomized to perform inspiratory muscle training with a placebo load (MIP 2%) or with moderate intensity (MIP 30%). Upon the randomization, participants will initiate inspiratory musculature training. The exams of HbA1c, glucose and ventilatory muscle strength tests will be performed in three moments: 1) at the initial assessment, 2) in the eighth week of inspiratory muscle training, and 3) at the end of the training (twelfth) week. During inspiratory muscle training, individuals will attend on Hospital de Clinicas de Porto Alegre, once a week, to the supervision of the way the exercise is being performed. Furthermore, it will be set to load on the PowerBreathe ® device for the following week.

Inclusion Criteria:

• Type 2 diabetes;
• 30 years and older;
• HbA1c from 7,5 to 10%.

Exclusion Criteria:

• Pregnant women;
• Pulmonary disease (chronic obstructive pulmonary disease, exercise-induced asthma, idiopathic pulmonary fibrosis, sarcoidosis and lung neoplasms);
• Neuromuscular disease;
• Body mass index > 35 kg/m²;
• Individuals who perform physical exercise more than twice a week;
• Current smoking.