Clay colored stools are associated with biliary duct obstruction. Any type of gallbladder disease can cause this and I would suggest further evaluation.
The first test to consider would be an abdominal ultrasound and liver function tests. If there are suspicious or inconclusive results, you may want to consider an ERCP or MRCP, which would be the most comprehensive test we have to evaluate the biliary tree.
To answer your questions:
1) Exercise may make the symptoms worse, however I would ensure there is no gallbladder cause first.
2) Again, it may be - but with the clay colored stools, I would exclude the gallbladder.
3) I would suggest an abdominal ultrasound and liver function tests as initial studies.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Thanks,
Kevin, M.D.