Association between Physical Activity and Serum Bilirubin Levels and Its Potential Modulating Effect in Trained and Untrained Adult Males
Musa Ibrahim, Mohammed Mabrouk, Yusuf Tanko
International Journal of Applied Exercise Physiology
Abstract: Why studies over the last two decades had shown low levels of serum bilirubin to be associated with high risk for varieties of systemic diseases in human, we propose that one potential modifiable behavior to increase bilirubin levels is physical activity. The purpose of this study was to examine the association between physical activity and serum bilirubin levels and its potential modulating effect among trained and untrained adult males. Employing purposeful sampling technique, 20 trained and 20 untrained adult males were recruited for this study following inclusion and exclusion criteria. The university institutional review board (ABUTH/HREC/TRG/36) gave approval for all procedures in accordance with the Declaration of Helsinki. Blood samples were taken to measured serum total bilirubin and leukocyte counts respectively from all subjects at rest. The VO2Max was estimated from a standard regression equation. The independent students-t -test was used to compare values between the two groups. Linear regression analysis was also used for prediction of any association. The level of significance was set at P< 0.05. Our result showed that VO2 max exhibited significant differences between the trained and untrained, leukocyte counts in the untrained group (140.10±1.65 x 50 mm3) was significantly (p< 0.05) higher compared to the trained group (134.50±2.46 x 50 mm3). On the other hand, serum total bilirubin in the trained group (11.35±2.6 mmol/l) was significantly (p < 0.05) higher compared to the untrained group (4.80±1.6 mmol/l). The VO2Max, correlated positively with serum total bilirubin (p < 0.0001), in both the untrained group (R2= 0.002, +0.045) and in the trained group (R2= 0.088, +0.297) respectively. In addition, Leukocyte counts correlated negatively with serum total bilirubin (p < 0.0001), in the untrained group (R2= 0.162, -0.403) and correlated positively in the trained group (R2= 0.032, +0.178; p < 0.0001). With the exciting results revealed, physical activity was positively associated with bilirubin among the trained males in an increasing trend. This means that an increased physical activity might increase hemooxyginase-1 activity which is the enzyme responsible for the conversion of biliverdin to bilirubin. In addition, leukocyte counts in the untrained was higher compared to the trained which means the potential modulating effect of the bilirubin might be on inflammation process. This study is novel, as, to our knowledge, no studies to date have examined this association. This finding has implications for sports physicians, diagnosis or applied exercise physiology.
Keywords: trained, untrained, physical activity, bilirubin, leukocyte