title: Determinants of the daily rhythm of blood fluidity.
abstract: BACKGROUND
  Numerous processes in the living body exhibit daily rhythmicity. In this study, we characterized a daily rhythm of blood fluidity and identified its determinants.
  
  
  METHODS
  The subjects were nine young males. We measured the physiological parameters and performed hematological and biochemical analyses. We repeated the measurements six times during the day at 7:30 (just after getting up and before breakfast), 10:00, 13:30 (after lunch), 16:30, 19:30 (after dinner), and 21:30. The subjects performed sedentary work all day, and the contents and time of the meals were uniform. Investigation of blood rheology was based on Kikuchi's microchannel method.
  
  
  RESULTS
  Blood passage time varied significantly with time of day. Stepwise regression analysis was used to determine the significant factors affecting blood passage time. Body temperature, heartbeat, hematocrit, white blood cell and total cholesterol were significant determinants of blood passage time.
  
  
  CONCLUSIONS
  We confirmed that blood fluidity has a daily rhythm. In addition, we found that the determinants of blood fluidity included physiological parameters such as body temperature and heartbeat, hematological parameters such as hematocrit, and white blood cell and total cholesterol.
authors: Yasuda Women's College, Department of Kindergarten Education, Yasuhigashi 6-13-1, Asaminami-ku, Hiroshima 731-0153, Japan. kimura@yasuda-u.ac.jp.
authors: Tatsushi
authors: T
authors: Kimura
authors: Tsutomu
authors: T
authors: Inamizu
authors: Kiyokazu
authors: K
authors: Sekikawa
authors: Masayuki
authors: M
authors: Kakehashi
authors: Kiyoshi
authors: K
authors: Onari