Anyone experience runner's high?

[tomkkk]

neurotransmitters, chemical messengers in the brain that regulate everything we do and feel. Low levels of serotonin and/or norepinephrine are related to depression, excess levels of dopamine to schizophrenia, low levels of GABA to anxiety, etc.

Among the many neurotransmitters produced in the brain are endorphins, natural opiates that increase pleasure and reduce pain (opium, morphine, and heroine mimic the effects of endorphins). Endorphins are produced during times of pain and strenuous exercise. Are any of you long distance runners or swimmers, and if so have you experienced a leap into "runner's high"? Or are any of you who've been through childbirth or emergencies familiar with this transcendent feeling? If you've experienced "runner's high," what were the conditions and how did it feel?