Often referred to as the body’s painkillers, endorphins are compounds that interact with the opiate receptors in the brain, stimulating a relaxing effect and increasing your tolerance for pain. While caffeine has a marked effect on the pituitary and adrenal glands, as well as the central nervous system, its relationship with endorphins is somewhat more complicated.
The Caffeine Effect
According to the Journal of Young Investigators website, caffeine mimics the chemical structure of certain neurotransmitters called adenosine. These molecules, which are primarily responsible for creating sensations of sleepiness and drowsiness, become blocked by the caffeine and are impaired in their task of shutting down the body for sleep. While in the brain, caffeine speeds up the rate at which neurons fire, inducing a state of fight or flight in the pituitary gland, which then stimulates the sympathetic nervous system by releasing adrenaline. As a result of this process, some individuals feel a boost in alertness and mood, which is often associated with the release of endorphins.
Like adrenaline, endorphins are also produced by the pituitary and hypothalamus glands, and are circulated through the body. The McGill Office for Science and Society website calls these molecules endogenous morphine due to their properties of relieving pain. As endorphins become released, a wide number of nerve receptors bind to them as if they were opiates, resulting in an increase of your pain threshold. Exercise, acupuncture and sexual intercourse have been consistently linked with increased levels of endorphins.
Caffeine and Endorphins
A study by Michael Alan Arnold, Ph.D. et al., published in "Life Sciences" in 1982 found that caffeine created a partial endorphin release by stimulating beta-endorphin levels in the blood but not in the cerebrospinal fluid. In other words, caffeine caused an immediate and sustained release of endorphins in the blood, but not in tissues or nerve clusters affected by the cerebrospinal fluid. As a result, it has been suggested that, while the caffeine itself does release certain endorphins in the body, the pleasant sensations and moods associated with caffeinated products such as chocolate and coffee may also contribute to the endorphin release.
Health and Safety
Although most healthy adults can consume caffeine in quantities of 200 to 300 milligrams a day, or 2 to 3 cups of coffee, excess caffeine intake can lead to symptoms such as nervousness, nausea, dizziness, dehydration, upset stomach, muscle tremors and irritability. Caffeine dependency can occur in dosages as few as 100 milligrams a day, and you may experience withdrawal symptoms if you discontinue or alter your caffeine consumption. Talk to your doctor about safe limits of caffeine intake for your body.