Marijuana isn't the only way individuals have been choosing to get high in Colorado. A recent article suggests perhaps the pathway to another addictive high, the "runners high" may be related to the "buzz" one feels when smoking marijuana, if they ever have. The similarity comes from the brain's endocannabinoid system, the same system that is stimulated by the "active ingredient" of marijuana, Δ9-tetrahydrocannabinol, or more commonly known as THC. This new mechanism for the runners high comes about as German researchers found that the classical idea of a runners high, the release of endorphins following a run, was perhaps not as likely since endorphins could not cross the blood-brain barrier. Of course, this doesn't totally rule out the role of endorphins in the runner's high, but it did lead researchers to ask more questions and explore anandamide, a lipid-soluble endocannabinoid, capable of crossing the blood-brain barrier which is also found in high concentrations following a running workout. In other words, because anandamide can cross the blood-brain barrier, it very well could be responsible for the runner's high individuals feel post-workout.
To test their hypothesis, researches conducted a study on mice where the mice were first split into two groups: one group allowed to exercise 5 hours daily on a running wheel, while the other group remained sedentary. Overall, it was found that the running group was both less anxious (as measured by observing tendency to "dart" from light to dark in order to hide) and had a lesser reaction to pain (as measured by the tendency to jump or lick their paws when placed on a hot plate). It was further found that endorphin antagonists did not significantly affect the results described above, while endocannabinoid antagonists seemed to inhibit anti-pain and anti-anxiety effects, despite allowing the mice to run for hours.
Overall, it appears that anandamide may play a role in the "runners high" one feels after a satisfying run. If anything, the pathway to a runners high may be more complex than previously thought, and further research may provide more insight into the complete picture. Nonetheless, a runner's high is legal in every state, is free, and should be considered anytime one feels the need to blow off some steam.
The abstract for the study may be found here.
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ReplyDeleteInterestingly, this article relates to the materials that we just studied in physiology part of the TBL regarding the effects of hormonal changes in women which required a different water composition and supplemental intakes needed to replenish the woman body during and post-exercise. I just wondered if men and women will achieve the same level of runner's high due to the physiologic differences between the two? I found an article that addressed the bidirectional interaction between the endocannabinoid system and the gonadal hormones where changes in gonadal hormones levels can alter the endocannabinoid signaling. There is an obvious link here.
ReplyDeleteThe link to my article is http://www.ncbi.nlm.nih.gov/pubmed/22210740
That's an interesting thought Khoa and one I had not thought of. I think this could certainly provide us with a more complete picture, and you're right, it appears that gonadal hormones do in fact alter endocannabinoid signaling. Though we need more research to really determine the extent, I would suspect that these gonadal hormones somehow slightly inhibit the "high" felt from running during the luteal phase of the menstrual cycle in females. My guess is this is because female bodies', evolutionarily speaking, inhibit exercise, including the endocannabinoidal "high" in order to limit the loss of fat that could occur and may be needed if a pregnancy were to occur.
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