The fight-or-flight hormone, adrenaline, functions as a signalling molecule by binding to a protein coded for by the ADBR2 gene (beta-2 adrenergic receptor).  This receptor plays a key role in skeletal muscle, cardiovascular, respiratory, metabolic and hormonal systems. The ADRB2_2 genetic variations are associated with obesity and the effect of weight loss interventions.


Global population distribution:

Source: 1000 Genome Project. Global averages for both sexes







More about ADRB2_2


The ADRB2 gene encodes for the beta-2 adrenergic receptor which is expressed within many cells in the body. It has a key regulatory role in the skeletal muscle, cardiovascular, respiratory, metabolic, and hormonal systems within the body which can all impact upon exercise performance.

Several polymorphisms have been described for the ADRB2 gene that affect the function of this receptor. FitnessGenes tests for two of these polymorphisms that we’ve named ADRB2_1 and ADRB2_2.

Stimulation of beta-2 receptors promotes blood flow and activation of systems that are important for the fight-or-flight response. For example, it stimulates relaxation of smooth muscle in the intestine and thus delays digestion. It also aids in relaxing airways, promoting glycogen turnover in the liver and skeletal muscles, as well as insulin secretion. Within the cardiovascular system, beta-2 receptor stimulation increases heart rate, stroke volume, cardiac output and regulates blood pressure. In addition, ADRB2 receptors are also found in fat cells, in which they actively engage in the breakdown of fat (lipolysis).

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