Researchers using PET scans to study the opioid system in long-distance runners are likely to find increased brain levels of _____ following a long run.
A)pepsin
B)endorphins
C)prolactin
D)insulin

Question

Quizplus · Accepted Answer

Endorphins are natural opioids produced by the body that help to regulate pain and promote a feeling of well-being. Long-distance running has been found to activate the release of endorphins, which can reduce pain sensitivity and produce a "runner's high." PET scans can detect increased activity in the brain's opioid receptors, indicating higher levels of endorphins present.

Researchers Using PET Scans to Study the Opioid System in Long-Distance