I'll bet your pack straps cut off the blood return from your arms and the flexing of [your shoulders]using the poles pumps more blood through them. I just hated carrying an unused pole over my shoulder. I guess I don't really carry them much in the summer unless I'm going up into snow or steep non-technical rock, but I carry poles in the winter because I ski camp.
Jim
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These are my own opinions based on wisdom earned through many wrong decisions. Your mileage may vary.