Although the effects of cold on blood pressure are established among healthy people, the effects among risk groups, such as hypertensive people, are not known. In addition to blood pressure, information on cardiac electrical activity or autonomic regulation are needed. Cardiovascular responses in the cold could be different among hypertensive people because of disturbances in autonomic nervous system and the circulatory regulation or function, such as aortic stiffening and increased vasomotor tone of peripheral arteries due to endothelial dysfunction associated with the disease. To assess this, a controlled experiment employing a cold exposure similar to everyday winter circumstances in a subarctic climate was performed in a climatic chamber.