As marijuana legalization and tolerance spreads across the country, it’s not hard to imagine a day in the not-too-distant future when sparking a J in the evening is as common as kicking back with a glass of cab. But despite the fact that a rising number of people are using weed (in the past year, 32 percent of 18-to-25-year-olds and 10 percent of those 26 and older have toked up), its effects on the body remain largely a mystery.
Since cannabis is classified as a Schedule 1 drug and considered illegal by the federal government, “there are still a lot of incompletes in the research,” says Damon Raskin, MD, a board-certified internist and diplomat of the American Board of Addiction Medicine.
But, of course, we do know that it has a profound impact — chiefly on cognitive function. “The primary active compound in cannabis, THC, mimics substances that we naturally produce in our bodies, called endocannabinoids, that help maintain health and balance at a cellular level,” says Dustin Sulak, DO, an osteopathic physician in Falmouth, Maine. “In the brain, endocannabinoids function by controlling the release of neurotransmitters. In other areas of the body, they reduce inflammation, relax muscles, protect damaged tissue, regulate metabolism and appetite, and much more.”
Basically, we have built-in receptors for cannabis — which is what makes marijuana unique compared with other drugs, such as alcohol, which the body treats like a poison. “When an individual uses cannabis, these same physiologic events are triggered,” Sulak explains to Yahoo Health. “The cognitive effects of THC are related to its neurotransmitter-modulating capabilities in areas of the brain that control memory, pleasure, emotion, pain, and movement. The effects of THC elsewhere in the body are often less noticeable, but also significant.”
Exactly what happens when you get baked depends on the type of administration and potency of the weed. “When inhaled, whether vaporized or smoked, the cannabinoids enter the bloodstream fairly quickly via the capillaries,” says Rachna Patel, MD, a medical marijuana expert based in Walnut Creek, California. You’ll feel the effects nearly instantaneously, they’ll build up for the next half hour, and then slowly dissipate over the course of a few hours.
But when pot’s ingested, “it takes about two hours for the cannabinoids to take hold because they get processed in the liver,” Patel tells Yahoo Health. Typically, you’ll feel high for eight to 10 hours once it sets in.
In addition, marijuana is way stronger today than it was decades ago. “In the 1970s, the concentration of THC hovered around 1 to 2 percent,” Raskin says. “Today, it’s about 13 percent or higher.” What’s more, when you eat cannabis, the THC goes through a process that makes it four times more psychoactive than if you’d inhaled it. And with edibles on the rise (The Denver Post reported that THC-laced confections now make up more than 45 percent of the legal marijuana marketplace), people are experiencing increasingly intense reactions.
With all that in mind, here’s a peek at some of the trippy stuff that happens in your bod when you get high on marijuana. (Aside from changes to your mouth and lungs, which are particularly affected if you smoke weed, the rest of these bodily effects occur no matter what form you partake in — joints, bongs, vaping, or edibles.)
This is the main area that’s impacted after you indulge in a little herbal refreshment. Not only does cerebral blood flow surge, but marijuana binds to cannabinoid receptors in the brain and alters their normal function, triggering a flurry of cognitive side effects.
For one thing, THC stimulates neurons that aren’t normally activated. “That can lead to enhanced sensations and perceptual changes,” Raskin says. A big one: You tend to “perseverate” more, meaning you tend to linger on a word, action, or thought longer than you normally would. You also might be more sensitive to sound, color, taste, smell, and touch, which is why people often report increased creativity when high.
It also affects your mood; you’ll probably be in a chillaxed state of mind. “The neurochemical dopamine is released, which causes pleasurable feelings of euphoria and relaxation,” Raskin says.
Or, you could swing the other way, and have a freak-out. There are more than 85 chemicals in marijuana, the main ingredients of which are THC and CBD. THC is the psychoactive compound, meaning it’s what makes you high; CBD is the calming compound that gives you a mellow vibe. “The ratio of THC to CBD varies depending on the strain you buy; the higher the proportion of THC, the stronger the effects,” addiction psychiatrist Kevin Hill, MD, director of the Substance Abuse Consultation Service at McLean Hospital, assistant professor of psychiatry at Harvard Medical School, and author of Marijuana: The Unbiased Truth About the World’s Most Popular Weed, tells Yahoo Health. “Synthetic marijuana is particularly potent.” It doesn’t contain any CBDs, so the paranoia-inducing THC is left unchecked.
In addition, marijuana targets the hippocampus, where short-term memory is located. “It can temporarily impair your ability to form new memories and learn things,” Raskin says. “The cerebellum — the area of the brain responsible for coordination — is hit, too. That’s why people describe the perception of time slowing way down, and have difficulty with balance and driving.”
The frontal lobes, which are associated with decision-making, are another key area that cannabis targets. “When you use marijuana, your judgment is not operating optimally,” says Hill. “You may make choices you otherwise wouldn’t, which is one of the biggest risks.” Whether it’s a bad call to get behind the wheel or to make out with your best friend’s boyfriend, weed can lead you down a dangerous path.
Finally, in case you’ve ever wondered what’s up with the munchies, researchers recently discovered that, when influenced by cannabanoids, neurons in the brain that usually signal you’re full switch gears and instead send out hunger signals. Ahem, so put the Ben & Jerry’s on lockdown.
The eyes are the windows to a pot-user’s soul: Changes to your peepers — like enlarged pupils and a bloodshot look — are a dead giveaway of being stoned. Although the jury’s still out on why your pupils grow, the red-eyed hound dog effect is thanks to an uptick of blood flowing through your capillaries. “Marijuana opens up your blood vessels, a process called vasodilation,” explains Raskin.
Mouth and Lungs
Particularly when smoked, weed is not your mouth’s BFF. The smoke, tar, and other chemicals it contains leads to irritation in your esophagus, lungs, and larynx. “Compared to cigarettes, it’s particularly harsh because you’re smoking it unfiltered,” Hill says. You might cough when taking a toke; that’s a protective mechanism to shield your body from toxins.
As for why some people get cottonmouth? Still up in the air.
Puff per puff, a joint can do more damage to your airways than a cigarette can, because pot smokers tend to inhale deeply and hold their breath, exposing their lungs to more tar, according to the American Lung Association. This makes the cells lining your lungs less adept at filtering out dust and bacteria and, over time, can result in chronic bronchitis, coughing, and (yuck) excess phlegm production.
What does spin class have in common with a spliff? Your heart starts to race — increasing as much as 20 to 30 percent, according to Raskin.
If you’ve been praying to the porcelain gods, studies suggest that a doobie might settle your tummy. “THC relates to the nausea center in your brain, and helps suppress an upset stomach and vomiting,” Raskin says.
According to research published in the European Journal of Immunology, cannabis seems to suppress immune function and increase risk of infections and even cancer.
Taking too many reefer breaks might do damage to a guy’s joystick. “There have been a few studies showing that marijuana can make it harder to get or maintain an erection,” says Christopher Asandra, MD, chief medical officer of NuMale Medical Center. “It can contribute to lower levels of testosterone, and some studies have even shown that it inhibits the nervous system itself, resulting in an inability to achieve an erection. In addition, marijuana can lead to premature ejaculation or make it more difficult for men to climax.” Yikes.
But that’s not all: A study from the University of Sheffield found that men who use cannabis were nearly twice as likely to have abnormal sperm as those who abstained. Plus, according to recent research from the University of Copenhagen, guys who partake in ganja at least once a week have nearly one-third lower sperm count than non-tokers.
And women aren’t off the hook; it can up the chances of female infertility, too. A study published in the journal Epidemiology linked marijuana use to ovulatory abnormalities.
Still, there is a silver lining for dudes who get sexy-time stage fright: “Marijuana can lead to increased relaxation, which might help combat performance anxiety,” Asandra says.
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