Anna Lembke

What does it feel like,” I asked, “immersing yourself in cold water?” I have an aversion to cold water myself, and couldn’t tolerate those temperatures for even a few seconds.
“For the first five to ten seconds, my body is screaming: Stop, you’re killing yourself. It’s that painful.”
“I can imagine.”
“But I tell myself it’s time limited, and it’s worth it. After the initial shock, my skin goes numb. Right after I get out, I feel high. It’s exactly like a drug . . . like how I remember ecstasy or recreational Vicodin. Incredible. I feel great for hours.”

Exercise increases many of the neurotransmitters involved in positive mood regulation: dopamine, serotonin, norepinephrine, epinephrine, endocannabinoids, and endogenous opioid peptides (endorphins). Exercise contributes to the birth of new neurons and supporting glial cells. Exercise even reduces the likelihood of using and getting addicted to drugs.

Exercise has a more profound and sustained positive effect on mood, anxiety, cognition, energy, and sleep than any pill I can prescribe.