Two important mechanisms play a major role in the pathogenesis of type 2 diabetes: insulin resistance of the target tissues and the impaired insulin secretion from pancreatic β-cells. Postprandial factors (such as insulin) are perceived by the human brain and induce signals that regulate glucose metabolism via the parasympathetic nervous system.

Deep breathing exercise can increase parasympathetic nerve activity. Heart rate variability (HRV) in healthy people can be significantly increased by deep breathing maneuvers, indicating a shift from sympathetic activity to parasympathetic activity.

The hypothesis is that this postprandial shift results in a change in peripheral glucose metabolism. In turn, the increased parasympathetic activity could potentially result in a change in postprandial insulin sensitivity or secretion.

To test this hypothesis, this study investigates the effect of deep breathing exercise versus normal breathing on insulin sensitivity, on insulin secretion, glucose tolerance, resting energy expenditure, and on parasympathetic tone (analysis of heart rate variability).

Inclusion Criteria:

• HbA1c <6.5%
• Must be able to understand the explanations of the study and the instructions

Exclusion Criteria:

• Any relevant (according to investigator's judgment) cardiovascular disease
• Neurological and psychiatric disorders
• Diabetes mellitus
• Asthma