Complex sentence: While taking a polygraph test you wear a blood pressure device to measure your fluctuations, respiration is measured by wearing pneumographs around your chest, and finally electrodes are placed on the subject's fingers to measure skin conductivity.
Split into simpler sentences: While taking a polygraph test the subject wears a blood pressure device to measure blood pressure fluctuations. Respiration is measured by wearing pneumographs around the chest, and finally electrodes are placed on the subject's fingers to measure skin conductivity.