In this paper we tested a group of 66 healthy volunteers in terms of the influence of circadian rhythm on selected parameters of the coagulation system and fibrinolytic system. Blood was collected at 6-hour intervals, at 8 am, 2 pm, 8 pm and 2 am. Circadian variability was observed in the coagulation system parameters as well as in the fibrinolytic system. We observed increased platelet aggregation, APTT prolongation, along with increased levels of factors (fibrinogen, PAI-1) and PAP and TAT complexes that influence coagulation and fibrinolysis systems, in the blood samples collected in the morning (8 am). We also demonstrated a circadian rhythm in the number of circulating platelets (PLT), with a peak in the afternoon (2 pm) accompanied by increased concentrations of t-PA, D-dimers and PT prolongation. Based on the obtained results it was possible to conclude that circadian rhythm had an influence on the activation of coagulation processes in the morning, with a progressive activation of fibrinolysis up to the afternoon. Our results may be helpful in determining the transient risk of cardiovascular events, including myocardial infarction and ischemic stroke, and hence, can contribute to the effective prevention of such events. Such observations may also become a starting point of departure for further studies aimed at determining the circadian effect of secretion of parameters in the hemostasis system on the other systems and parameters in the human body.

Binocular vision is the most important visual cue for spatial orientation in many sports. In this study, we investigated how binocular vision was influenced by an eye training program that may be used to improve individual's oculomotor function. The experiment involved twenty-four female student athletes from team ball sports (soccer, basketball, handball). After an initial testing session, 12 participants were randomly allocated to the experimental group. Optometric investigation which included synoptophore testing and a test of dissociated horizontal phoria based on the Maddox method was performed three times: before the experiment, after eight weeks of eye training (3 times a week for 20 minutes), and four weeks after the experiment was terminated. Eye exercise methodology was based on orthoptic, sport and psychological aspects of performance. The phoria screening examination showed that exophoria was the most frequent disorder of binocular vision. Low fusional vergence range was also observed. Following the training period, 3 of the 6 oculomotor variables improved. The greatest effect was observed in near dissociated phoria (χ2 =14.56, p=0.001 for the right eye; χ2 =14.757, p=0.001 for the left eye) and fusional convergence (χ2 =8.522, p=0.014). The results of the retention test conducted four weeks after the experiment confirmed the effectiveness of the vision training program. The results of the study suggest that binocular functions are trainable and can be improved by means of appropriate visual training.

The number of hematopoietic stem/progenitor cells (HSPCs) circulating in peripheral blood (PB) is regulated by a circadian rhythm, and more HSPCs circulate in PB in the morning hours than at night. Different mechanisms have been proposed that might regulate this process, including changes in tonus of β-adrenergic innervation of bone marrow (BM) tissue. Our group reported that in mice circadian changes in the number of HSPCs circulating in PB correlates with diurnal activation of the complement cascade (ComC) and that the mice deficient in C5 component of ComC (C5-KO mice) do not show circadian changes in the number of circulating HSPCs in PB. We also reported the existence of a gradient between PB and BM of a bioactive phosphosphingolipid, sphingosine-1-phosphate (S1P), which is a major PB chemottractant for BM-residing HSPCs. Based on these observations, we investigated activation of the ComC and the level of S1P in the PB of 66 healthy volunteers. We found that both ComC activation and the S1P level undergo changes in a circadian cycle. While the ComC becomes highly activated during deep sleep at 2 am, S1P becomes activated later, and its highest level is observed at 8 am, which precedes circadian egress of HSPCs from BM into PB. In sum, circadian activation of the ComC–S1P axis releases HSPCs from BM into PB.