This interventional study was aimed to investigate the effects of physical exercises and pineal gland on thrombin time and coagulation time in olfactory bulbectomy rats. The experiment was performed on 120 white male wistar rats weighing 100-150 gr. Animals were divided into two groups; control group and experimental group (olfactory bulbectomy and epiphysectomy). In both group animals were divided into three subgroups: control (without physical exercises), short-time physical exercises (5 minutes) and long-time physical exercise (20 minutes). Blood samples were collected from rat tail tip in several stages as before and after intervention, to determine of coagulation time. Exercise plans included; swimming on water pool until 5 minute and 20 minute in experimental and control groups. Then, thrombin time was measured for each tissue after autopsy of animals. The results revealed that short- time physical exercise significantly decreased thrombin time on different tissues of rats compared baseline values in control group (P<0.001). In contrast, long- time physical exercise significantly increased thrombin time on different tissues in interventional groups (P < 0.001). The findings of this study indicated that in experimental groups, coagulation time increased after long-time physical exercise but decreased after short-time physical exercises. In conclusion, this study suggested that there is a functional relationship between the olfactory bulb and pineal gland via its regulation of circadian rhythms and exercise on changes of coagulation parameters in different tissues. Keywords: Thrombin time; coagulation time; physical exercise; olfactory bulbectomy; epiphysectomy and rat. Abbreviations: CT: coagulation time, TT: thrombin time, OB: olfactory bulbectomy NOB: without olfactory bulbectomy, PEX: physical exercise, NPEX: without physical exercise, EP: epiphysectomy, NEP: without epiphysectomy, SCN: suprachiasmatic nucleus, vWF: von Willebrand factor, aPTT: activated partial thromboplastin time, tPA: tissue plasminogen activato
