What Causes Runner's High?

What chemicals were initially thought to cause runner's high, and what chemicals are now believed to be more responsible for the feeling of happiness and calm?

• Endocannabinoids, then endorphins

• Dopamine, then serotonin

• Endorphins, then endocannabinoids

• Serotonin, then dopamine

Why are endorphins likely not the main cause of the general feelings of happiness experienced during runner's high?

• They only affect muscle pain, not mood.

• They are too large to cross into the brain.

• They are quickly broken down by the body.

• They only work in animals, not humans.

What are some effects of endocannabinoids in the body?

• Increasing heart rate and blood pressure.

• Soothing anxiety and reducing pain sensitivity.

• Boosting muscle growth and strength.

• Improving vision and hearing.

In the mouse experiment, what happened to the running mice when a drug blocked anandamide from working?

• They became more calm and less sensitive to pain.

• They showed no change in their reaction to pain.

• They became more anxious and sensitive to pain.

• They started running faster and longer.