As long ago as 5,000 years ago, humans were consuming caffeinated beverages such as tea. Tea and coffee throughout history have been a highly valued and sought after commodity. Caffeine is naturally occurring in more than 60 foods including such well-known favorites as cocoa beans, coffee, and tea.

1. Caffeine stimulates the central nervous system which does help you to feel more alert and attentive. The flip side is that it may also exacerbate anxiety and the symptoms of anxiety. However, since caffeine does not build up in the body, the physical impacts of it will be excreted within 3-4 hours in healthy people. If you are a smoker, your body will metabolize it even faster.

2. For athletes, caffeine may enhance performance by helping you feel more alert and attentive.

3. Caffeinated beverages still count towards your overall daily fluid intake goals. Although known for its mild diuretic effect, caffeine does not cause electrolyte imbalance or dehydration. Although it counts towards your daily intake, be sure to drink lots of other fluids too.

4. Tolerance for caffeine can build up over time, so the effects may not be as impactful for more frequent drinkers.

5. Caffeine passes through breastmilk. Your intake will probably not bother your baby if you keep it down 1-2 cups per day. So enjoy your breakfast coffee and kombuchas in moderation.

6. Caffeine can inhibit iron and calcium absorption, so if you are worried about getting enough of either in your diet, make sure to space your calcium-rich foods or iron-rich foods away from your caffeinated beverages. One study found of iron absorption was reduced by nearly 40 percent when a cup of coffee was part of the meal and consumed with a hamburger.

7. Chocolate contains a surprisingly small amount of caffeine from what you might have assumed! The 5 milligrams of caffeine found in a cup of chocolate milk is small when compared with the more than 110 milligrams of caffeine found in 5 ounces of brewed coffee.

8. Drip coffee will give you a bigger caffeine boost because although it has less caffeine in it than an espresso per milliliter because you typically have a larger serving so it will provide you more in total.

9. Although there has been research into potential negative effects of caffeine, there has been no link between caffeine and cancer, fibrocystic disease, blood cholesterol levels, infertility, birth defects, osteoporosis, inflammatory bowel disease, attention deficit disorder, cardiovascular disease or ulcers. Even for those people who are worried about hypertension, studies have shown that caffeine may result only in a short, small rise in blood pressure, less of an impact that running or doing jumping jacks. Although caffeine may irritate your stomach lining.

10. You become more sensitive to caffeine with age, although the National Institutes of Health say that the effects of caffeine are the same for adults and children, although gender, ethnicity, and if you are a smoker or not, may cause differences in metabolism rates.

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