After running for some time, a marathon runner may "hit a stride" and be able to continue with little pain. The runner is experiencing the effects of which body chemical?

Question

Quizplus · Accepted Answer

Endorphins are chemical compounds that are produced by the body in response to physical activity, excitement, pain, or other stimuli. They bind to receptors in the brain and spinal cord to reduce pain perception and produce a feeling of euphoria or “runner’s high.” This can help marathon runners to push through the pain and fatigue and continue running with greater ease.

After Running for Some Time, a Marathon Runner May "Hit