Research on Effects of Swimming in Cold Water on Ultrastructures of Cardiac Muscle Cells in Mice

The mice were divided into three groups, the group swimming in cold water (4℃ and 10℃), group swimming in warm water (25℃) and the control group. Applying the transmission electron microscope (TEM) the ultrastructures of cardiac muscle cells of the mice were observed. It was shown that there were no remarkable changes in the ultrastructures of the cardiac muscle cells between the group swimming in 4℃ cold water and the group swimming in 10℃ cold water. There were large numbers of mitochondria in cytoplasm of their cardiac muscles. The volumes of the mitochondria were great, they distributed densely and there were abundant osmiophilic particles among the cristae. In cardiac muscle cells there were glycogen particles increased significantly and distributing in clusters. Observed under the electron microscope no traumatic change could be seen in the ultrastructures of the cardiac muscle cells of the mice. The mitochondria, osmiophilic particles and glycogen in cardiac muscle cells of the mice group swimming in warm water were similar to those of the control group. The results indicate that prolonged and moderate swimming in cold water contributes to the improvement of the ultrastructures of cardiac muscle cells, energy metabolism and energy reserve as well as to the promotion of activities of cardiac muscle cells, showing that prolonged and moderate swimming in winter contributes to improving cardiac functions of people.