The healthy perks of caffeine

Naturally produced in more than 60 plants, caffeine is the world's most frequently used drug.
Some 80 percent of Americans regularly consume caffeine, most often in the form of coffee. People have tried to link caffeine to all sorts of ills, but it has never been proved. In reality, caffeine may actually enhance your health. Over the past five years, scientific studies have shown that caffeine's benefits can range from increased energy and improved mood to reduced risk for life-threatening diseases. Here's the latest on five potential benefits.

Researchers believe caffeine blocks the action of adenosine, a brain chemical that may produce tiredness. When you consume caffeine, it travels quickly to the brain, where it counters adenosine's depressant effects. Caffeine's impact is greatest when you are tired. Researchers at Harvard Medical School examined caffeine's effect on sleep-deprived men. They found that small, frequent doses (equivalent to two ounces of coffee) taken once an hour improved performance on cognitive tests compared to a placebo. Instead of guzzling your cup of joe, it is probably just as good, if not better, to sip as you are working or on a long drive. Just cut off the supply well before bedtime as caffeine's stimulating effect can last four to six hours.

Caffeine has shown to improve endurance for running, biking, swimming, and rowing, with the strongest effect for activities lasting longer than an hour. Some research has shown that caffeine helps stimulate muscle contractions, but most likely enhances performance in the same way it helps boost alertness - by counteracting the fatiguing effects of adenosine. And contrary to popular belief, caffeine is not dehydrating, so you need not worry that a pre-exercise infusion will interfere with hydration. Recent research has revealed that caffeine does not result in the increased "need to go," but instead, that need is simply caused by fluid intake, regardless of whether the beverage is caffeinated or not.

Tension headaches are caused by swelling of the blood vessels in your head, which press on nerves, causing pain. Tension headaches are the most common type of headache; 88 percent of women and 69 percent of men experience them. Caffeine relieves pain because it is a vasoconstrictor, which contracts blood vessels. Pairing caffeine with ibuprofen can enhance the effectiveness of the caffeine. Caffeine actually works faster than ibuprofen because it enters your bloodstream quickly, reaching peak concentration within 30 to 60 minutes. A big mug of coffee can help relieve a headache, but taking a painkiller with it provides extended relief because caffeine's vasoconstrictive effects only last an hour and a half.

If your boss is a coffee drinker, early morning might be the best time to ask for a raise. The reason? Caffeine enhances the brain's ability to evaluate arguments. Researchers in Australia asked people to read arguments that contradicted their feelings on a given topic 40 minutes after drinking regular orange juice or orange juice laced with approximately 200 mg of caffeine. Those who consumed the caffeinated beverage were more likely to change their view. The study links caffeine to factors of persuasion, such as alertness, memory, and logical reasoning.

Parkinson's disease is a brain disorder in which nerve cells do not produce enough dopamine, a chemical responsible for aiding in steady, coordinated movement. Researchers for the Veteran's Administration analyzed both the coffee and caffeine intake of more than 8,000 men over 30 years and found that the men who didn't drink coffee or consume other forms of caffeine were five times more likely to develop the disease than those who consumed the largest amounts. Men who drank 28 ounces of coffee (that's three and half 8-ounce cups) or more a day had the lowest Parkinson's risk. Studies of women have been less conclusive, perhaps because estrogen can inhibit caffeine metabolism. Researchers are unsure of the exact reason caffeine helps. One theory suggests that caffeine may help bolster dopamine-producing neurons in the brain.

Starbucks Tall (12 ounces) 375 mg

Instant Coffee (8 ounces) 95 mg

Brewed Coffee (8 ounces) 60-80 mg*

Häagen-Dazs Coffee Ice Cream 58 mg

Starbucks espresso (1 ounce) 35 mg

Starbucks Tall Caffè Latte (12 ounces) 35 mg

Typical brewed decaf coffee (8 ounces) 5-10 mg

Typical iced tea (8 ounces) 47 mg

Typical brewed green tea (8 ounces) 30 mg

Arizona Iced Tea (16 ounces) 15-30 mg

Hershey's Special Dark (1.5 ounce bar) 31 mg

Hershey's Milk Chocolate (1.5 ounce bar) 10 mg

Hot chocolate (8 ounces) 3-32 mg

Maximum Strength NoDoz or Vivarin (1 tablet) 200 mg

Excedrin (2 tablets) 130 mg

Red Bull (8.3 ounces) 80 mg

Mountain Dew (12 ounces) 56 mg

Diet Coke (12 ounces) 47 mg

Sunkist Orange Soda (12 ounces) 42 mg

Dr. Pepper (12 ounces) 42 mg

Pepsi (12 ounces) 38 mg

Coca-Cola (12 ounces) 35 mg

Barq's Root Beer (12 ounces) 23 mg

* Caffeine content varies depending on brewing method, ratio of water to coffee, type of bean, and roasting process.