Hemodynamic changes in athletes' brains: is there any adaptation?

This study compared the hemodynamic changes in the prefrontal cortex during sprint interval training (SIT) and recovery periods in sedentary and athletes. SIT was performed on a cycling ergometer on 12 male athletes and 9 sedentary participants. A functional near-infrared spectroscopy (fNIRS) device was used to record the hemodynamic changes of the prefrontal cortex throughout the protocol. The oxyhemoglobin (Oxy-Hb) levels in the prefrontal cortex were increased significantly, and the power outputs were decreased in repetitive Wingate anaerobic tests (WAnTs) in Sedentary and Athletes group (p < 0.001). In addition, the Sedentary group had higher Oxy-Hb values (p < 0.001). However, the recovery times decreased significantly after all WAnTs (p < 0.05). Despite the increased fatigue, athletes performed better with less Oxy-Hb than the sedentary participants. Also, the recovery of the Oxy-Hb values in the prefrontal region was faster in athletes. These results may highlight a possible brain adaptation in athletes.

Geochemical and radionuclide profile of Tuzla geothermal field, Turkey.

Tuzla geothermal basin is situated in north-western Turkey on the Biga Peninsula, which is located at the west end of the Northern Anatolian Fault system. Soil and water samples were collected between August 2003 and June 2004 to initiate development of a geochemical profile of surface and subsurface waters in the geothermal basin and radionuclide concentrations in soils. All water samples were found to fall within Turkish Water Quality Class 4, meaning they were remarkably contaminated for any water consumption sector (industrial, human use or agricultural) based on sodium and chloride ions. Such waters could be used only after appropriate water treatment. The water samples are of the chloride type in terms of geochemical evaluation. Preliminary geochemical evidence shows that the N-S flowing part of the Tuzla River acts as a natural barrier within the basin. Heavy metal concentrations in the soil samples show slight elevations, especially those obtained from the east part of the basin where thermal springs are dominant. Geochemical calculations were carried out with PHREEQC software to determine equilibrium concentration of chemical species and saturation indices, by which it is suggested that chloride is the most important ligand to mobilize the heavy metals in the studied system. In addition, the activity concentration and gamma-absorbed dose rates of the terrestrial naturally occurring radionuclides were determined in the soil using gamma-ray spectrometry. The soil activity ranged from 42.77 to 988.66 Bq kg(-1) (averaging 138 Bq kg(-1)) for ( 238 )U, 13.27 to 106.31 Bq kg(-1) (averaging 32.42 Bq kg(-1)) for ( 232 )Th, and 99.28 to 935.36 Bq kg(-1) (averaging 515.44 Bq kg(-1)) for ( 40 )K. The highest value of ( 238 )U was found in the soil samples obtained from an area close to the hot spring.