<prompt> Bradycardia in athletes is due toIncreased vagal toneIncreased sympathetic toneDecreased cardiac outputLow venous return  <response>: A increased vagal tonePersons undergoing long term training develop bradycardia at rest. The resting pulse rates in some top class sportsmen atheletes for example. Zatopek. Borg are quite low. This bradycardia is believed to be due to excessive tone of the vagi. On the other hand, exercise of some intensity will cause less rise of pulse rate after trainingAthletic pseudonephritis ; prolonged, heavy exercise, increases proteins, cells and other abnormal substance in urine due to1. Decrease in renal blood flow RBE produces glomerular capillary hypoxia, and increases permeability to large molecules2. Increase in plasma proteins during exercise3. Decreased rate of RBF, thus larger time is required to filter these moleculerCauses of BradycardiaPhysiologicalPathologicalDrugs Sleep Athletes Hypothermia Hypothyroidism Heart attack CHD Degenerative process of aging Obstructive jaundice Increased intracranial pressure Beta blockers Channel blocker Digitalis and antiarrhythmic drugs. 