HOW THC MOVES THROUGH THE BODY

HOW THC MOVES THROUGH THE BODY

When marijuana is smoked, the rich blood supply of the lungs rapidly absorbs the THC. This applies to marijuana that is "vaporized" as well. Even though it is not burned, the THC that is mobilized from the plant material in the vaporizer is absorbed through the lungs. Because blood from the lungs goes directly from the heart to the brain, the high, as well as the effects on heart rate and blood vessels, occurs within minutes. Much of the THC is actually gone from the brain within a few hours after smoking. However, THC also accumulates in significant concentrations in other organs, such as the liver, kidneys, spleen, and testes. THC readily crosses from the blood of a pregnant woman into the placenta and reaches the developing fetus.

How the smoker smokes makes a difference in how much of the THC from the marijuana actually gets to the body. A cigarette allows for approximately 10 to 20 percent of the THC in the marijuana to be trans­ferred. A pipe is somewhat more efficient, allowing about 40 to 50 percent to transfer, and a water pipe (or bong) is quite efficient. Because the water pipe traps the smoke until it is inhaled, theoretically the only THC lost is what the smoker exhales. Vaporizers allow a very efficient transfer of THC because, in addition to taking advantage of the rich blood supply in the lungs, vaporized pot does not create smoke that can be irritating to the lungs and cause a person to limit his inhalation or to cough out a "hit" that is too big. This can be a problem as well, particularly when a smoker first switches to a vapor system. Smokers are used to the feeling of smoke in their lungs and often use that feeling as a gauge by which they estimate their intake. The vapor does not irritate the lungs, so that gauge is missing and some new vapor users take in far more THC than they intend until they figure out a new way to estimate their intake.

Although much of the high wears off relatively soon after smoking, THC remains in the body much longer. About half of the THC is still in the blood twenty hours after smoking. And once the blood carrying the THC passes through the liver, some of the THC is converted into other compounds that may remain there for several days. Some of these metab­olites have psychoactive effects as well, so that although the initial high may disappear within an hour or two, some of the effects of marijuana on mental and physical functions may last for days.

Not only may THC and its metabolites stay in the blood for days but they also stay in the fatty deposits of the body much longer because they are very lipid-soluble—they easily get absorbed into and stored in fat. THC stored in fatty deposits is released from these tissues slowly over a rather long period of time before finally being eliminated. What all this means is that about 30 percent of ingested THC (and its metabolites) may remain in the body a full week after smoking and may continue to affect mental and physical functions subtly. In fact, the remnants from a single large dose of THC may be detectable up to three weeks later.

All of these rules also apply when marijuana is eaten instead of smoked, except that less THC gets to the brain and it takes a lot longer for it to get there. When marijuana (or any drug) is taken into the stomach, the blood that absorbs it goes to the liver before flowing to the rest of the body (including the brain). This means two things: First, the liver breaks down some of the THC before it ever has a chance to affect the brain. Second, the remaining THC reaches the brain more slowly because of its indirect route through the bloodstream. However, because the body absorbs THC more slowly when marijuana is eaten, the peak levels of the drug last lon­ger (though they are lower than they would be if the same amount were smoked).

Whether the user eats or smokes marijuana and the accompanying differences in the way THC is distributed and metabolized appear to have a substantial impact on the kind of experience he has. Rather than experiencing a sudden change from being straight to being high, the marijuana eater experiences a slow and gradual shift that lasts longer. Many experienced users report that what happens after eating marijuana is more reminiscent of a mild mushroom or LSD trip; it's not simply "getting high." Because high levels of THC can cause hallucinogen-like experiences, people who have eaten marijuana and reported such feel­ings may actually have achieved higher levels of THC than many smok­ers—despite the fact that some of it is metabolized by the liver before it gets to the brain—because they ate a larger amount than they would likely have smoked.

CAFFEINE AND STRESS

CAFFEINE AND STRESS

Caffeine increases some of the normal stress responses because it increases the amount of adrenaline that is active in the body under stress­ful circumstances. Thus, it seems that caffeine users who find themselves under stress (or who use caffeine even more during stressful periods to work more effectively) may experience more of the effects that stress can produce. Adrenaline release increases blood pressure during stress, and the caffeine-induced rise adds to this. Thus, caffeine and stress together lead to greater bodily stress responses than either does alone.

CAFFEINE AND PANIC ATTACKS

In some people, caffeine can contribute to the experience of panic attacks, which generally come on suddenly and involve powerful feelings of threat and fear. The experience can be very debilitating for a brief period of time. It seems that caffeine is more likely to bring on panic attacks in people who have had them previously. However, relatively high doses of caffeine (greater than 700 milligrams) have been reported to lead to panic attacks in people who have never experienced them.

ENHANCEMENT OF PHYSICAL PERFORMANCE

Caffeine can slightly enhance physical endurance and delay fatigue asso­ciated with vigorous exercise in some people. One way that caffeine might accomplish this is by releasing fats into the blood for use as energy, enabling the body to conserve its other energy stores (in the form of stored sugars), thus allowing the athlete to sustain physical activity for a longer period of time. Caffeine may also help muscle performance during physical exercise, although the way this happens is not clear. What we do know is that caffeine dilates the bronchioles, making it easier for air to pass into the lungs. This would seem to have a beneficial effect on certain types of physical performance. Still, the most thorough studies of well-trained athletes are inconclusive. In some cases there appear to be performance-enhancing effects, and in others there are none. So the jury

remains out.

Two words of caution, though, for those who use caffeine for this pur­pose. Because caffeine causes an increased loss of water through urine production, a person exercising on caffeine may become dehydrated more rapidly during long periods of exercise such as distance running or cycling. This caution is particularly important for hot-weather exercisers. The other concern is the effects of caffeine on heart rate and heart rhythms. Strenuous exercise obviously stresses the heart, so a person with cardiovascular disease could experience problems while using caffeine to promote physical performance.

People who worry about their weight might be interested in the issue of fat metabolism. Products based on the supposed ability of caffeine and theophylline to "burn fat" include a theophylline cream placed on the market several years ago that was supposed to melt fat away. Just rub it on the offending fat pad! Unfortunately, the effectiveness of this treat­ment hasn't been established (one big problem is probably getting the theophylline through the skin and into the fat cells).

Likewise, there is tremendous interest in whether a combination of caf­feine and exercise can help to promote the burning of fat as fuel for weight loss. Fat cells really do have adenosine receptors, and xanthines really can cause a small release of stored fat, so some foods that include caffeine have been sold as fat burners. However, the scholarly research on these prod­ucts has demonstrated only small weight-loss effects. Coffee and its cous­ins may prove to be a useful part of weight-loss programs in the future, but at this point nothing "melts" fat except old-fashioned exercise and a healthy diet.

EFFECTS ON OTHER BODY PARTS

EFFECTS ON OTHER BODY PARTS

THE HEART

Caffeine affects the heart in two ways: it acts on brain centers that regu­late the cardiovascular system, and it acts directly on the heart. In people who are not tolerant to caffeine, a high dose (generally above 500 milli­grams—about four cups of strong coffee) can increase the heart rate by as much as ten to twenty beats per minute (from a baseline of eighty to ninety). In some, this dosage can result in brief periods of irregular heart­beat. However, in general, the morning cup of coffee does not have much effect on heart function in a healthy person.

There is controversy over the issue of caffeine and the gradual develop­ment of heart disease. At present, the scientific literature is inconsistent in its findings on the question of whether continued caffeine use increases the risk of heart disease or heart attack. One very large study of men found no relationship between coffee drinking and heart disease, while others have found an increased risk of heart attacks in coffee drinkers. Moderate caffeine consumption (up to 500 milligrams per day) probably does not place the user at significant risk for heart problems. Above that level, however, the risk of heart attack may increase. This would be particularly true for individuals with other risk factors for heart attack, such as smoking, being overweight, or having a family his­tory of heart disease.

Caffeine is also known to increase blood pressure, but generally this occurs with rather high doses and in people who already have difficulties with blood pressure regulation. For this reason, people with high blood pressure are often advised to avoid caffeine.

Cholesterol

An association between coffee drinking and cholesterol levels has been sus­pected for some time, yet it remains controversial. It is safe to say that the relationship has not been ruled out, but the picture remains unclear. One solid study has shown that five to six cups of coffee per day can increase LDI. cholesterol levels (this is the "bad" type of cholesterol as far as risk of heart disease is concerned) by 10 percent or more. This is not the case, however, if the coffee is prepared using a paper filter. While it is not clear exactly why filtered coffee fails to raise cholesterol levels, it is likely that oils from the cof­fee beans and other substances that promote fat buildup in the blood are trapped by the paper filter as the water passes over the coffee grounds.

THE KIDNEYS

The well-known bathroom break that follows the morning coffee is prob­ably caused both by a direct effect on the kidneys and by effects in the brain. There are adenosine receptors in the kidneys and caffeine acts on these, causing effects similar to those of diuretics, which increase urine production. Caffeine may also slow the release of an antidiuretic hormone from the brain that normally slows urine production.

THE DIGESTIVE SYSTEM

In coffee drinkers, the acids, oils, and caffeine can all irritate the stomach lining and promote secretion of acid, leading to gastritis (inflammation of the stomach). However, caffeine may not be the major villain, as decaf­feinated coffee has effects almost as great as caffeine-containing coffee. Although coffee was once blamed for ulcers, the primary cause of ulcers is now thought to be bacteria (Helicobacter pylori). Irritating agents like cof­fee and aspirin can contribute to the process by damaging the protective mucous lining of the stomach walls, but they probably don't cause ulcers on their own. In some individuals, caffeine in coffee can promote the reflux of stomach acid into the throat, resulting in painful heartburn.

THE RESPIRATORY SYSTEM

Caffeine and similar drugs have two quite separate effects on breathing.

The first was already mentioned: they stimulate the rate of breathing. The ophylline is sometimes used in treating premature infants with breathing problems. Xanthines also relax the smooth muscle in the bronchioles that take air into the lungs. This is very helpful in treating asthma, a disease in which breathing difficulties arise because these tubes constrict. Theophyl­line was used widely in the past to treat asthma and is still sometimes used today. However, concerns about side effects (restlessness, stomach upset) and the development of more effective treatments have diminished its use.

THE REPRODUCTIVE SYSTEM

Although studies in humans have not confirmed a link between caffeine consumption and birth defects, some studies report that babies born to women who used caffeine during pregnancy have lower birth weights. There is also some evidence that caffeine consumption (equivalent to more than one cup of coffee per day) can significantly reduce the chances of a woman becoming pregnant. Finally, there have been contradictory findings about the association between caffeine use and fibrocystic breast disease and eventual development of breast cancer. All of these associa­tions are questionable, and most studies do not support an association with the development of breast cancer.

THE EYES

Caffeine causes the tiny blood vessels in the eyes to constrict (become narrower) and thus decreases the flow of nutrients to the cells within the eyes and the clearing of waste products.