With a Starbucks on virtually every major city block, it's pretty clear that Americans love their coffee. Real estate trends notwithstanding, a 2013 National Coffee Association survey found that 83 percent of American adults drink an average of three cups a day. That's a whole lot of lattes.

But what exactly is all that caffeine doing to our bodies -- besides giving us that much-needed jolt to get out the door in the morning? Don't worry: We're not here to scare you off the stuff...though introverts may want to steer clear of it during certain crucial life-moments. Here, how our beloved caffeine fix can affect everything from our memory to -- hold onto those coffee cups -- how long we live.

Here's news that will cement a procrastinator's reliance on coffee: In addition to giving those prone to last-minute prep an extra boost of energy, say, the night before cramming for a big test or presentation, coffee also helps enhance memory. A study by John Hopkins researchers found that caffeine can have a positive effect on long-term memory, helping us strengthen recall a full 24 hours after consuming caffeine.

In the study, researchers gave participants a caffeine tablet or a placebo five minutes after having them study a series of images. The following day, the caffeine consumers were more likely to correctly distinguish whether shots in a new set of images were the same or simply similar to the images they had originally viewed.

Now if only coffee could help us forget the memory of all those painful all-nighters we've had to pull.

Ever feel like you'd just die if you didn't have that daily cup of joe? Well, a recent study suggests coffee might, in fact, help you live longer. Researchers found that those who consumed three to five cups of coffee per day had a 15 percent lower risk of premature death due to causes ranging from diabetes to heart disease than those who skipped a daily cup. And while the study only shows that there's an association -- rather than definitive proof -- between drinking coffee and evading premature death, we can confirm that coffee consumption makes us feel invincible on a daily basis.

If you're on the shy side, it turns out you might not jive with java. In his book, "Me, Myself, and Us: The Science of Personality and the Art of Well-Being," author Brian Little says caffeine may negatively affect an introvert's productivity after their morning trip to Starbucks.

"After ingesting about two cups of coffee, extraverts carry out tasks more efficiently, whereas introverts perform less well," he writes. "This deficit is magnified if the task they are engaging in is quantitative [think: math] and if it is done under time pressure." The thinking behind the theory is that introverts, who tend to operate at an optimal level of alertness, are over stimulated by caffeine consumption, making them more distracted and less likely to perform well when tackling tasks. But, hey, introverts have still got good ol' booze when it comes to overcoming their inhibitions, so there's that.

No surprise here. Just one cup of coffee takes us from zombie to superhero all before we've finished checking our morning email. But how exactly does caffeine do that, and why does it work so quickly? For starters, it easily bypasses the blood-brain barrier, the central nervous system's built-in barricade to foreign substances. This filter blocks bacteria, viruses and most drugs from entering the brain. But coffee slips through unimpeded. Within 30 minutes, caffeine has infiltrated the bloodstream and every cell in the body. Consider it the Navy SEAL of substances.

Once it's crossed that barrier, it blocks the activity of adenosine, a neurotransmitter that plays a role in making us tired, explains Marci Clow, MS, registered dietician and senior nutritionist for Rainbow Light supplements. "By blocking adenosine other neurotransmitters, we become more alert," she says. "Studies have found that the caffeine equivalent of about two cups of coffee can enhance cognitive function and mood among sleep-deprived people, and affect the specific areas of the brain responsible for memory and concentration."

All of which is good news for those of us wishing to continue our coffee addiction. Bottoms up!