Effects of winter swimming on haematological parameters

Fifteen healthy subjects (13 males and 2 females) were recruited among the participants to a 150 meters long swimming race in cold water (6 degrees C).
Red blood cells, white blood cells and platelets count increased significantly (4.7%, P = 0.005; 40.6%, P < 0.001 and 25.0%, P < 0.001, respectively).
Also a strong increase in the total number of neutrophil granulocytes, lymphocytes and monocytes was recorded (42.6%, P = 0.002, 58.2%, P = 0.001 and 27.5%, P = 0.021, respectively).