Stress And The Effects Of Caffeine

Stress is considered to be a normal part of the modern world, and caffeine-containing beverages are consumed by many people. But when a person who is stressed also ingests caffeine, the combination can lead to some potentially undesirable health effects.

Caffeine

Caffeine is a bitter, drug-like substance that occurs naturally in coffee beans, tea leaves, chocolate and kola nuts. It is well-known as a stimulant and the basis for a variety of drinks such as coffee, tea, hot cocoa and the popular "energy drinks." Those same stimulant properties can create problems, however, if an individual is particularly sensitive to caffeine or drinks a great deal of a preferred caffeinated beverage. Medline Plus reports that anxiety, insomnia, headaches and abnormal heart rhythms can be signs the body is reacting to caffeine.

Caffeine and Stress

Research on the combined effects of stress and caffeine has shown there is cause for concern, particularly if an individual already has a medical condition such as high blood pressure, or hypertension. Researchers at Duke University found compelling evidence that caffeine not only increases stress, as measured by hormone levels and blood pressure, but the effects persisted through the day. Adrenalin levels in study participants increased by 32 percent. A second study reported in the May 2000 "American Journal of Hypertension" noted similar results. The study found that participants who were considered high risk for hypertension, on the basis of family history and screening blood pressure measurements, developed blood pressure readings in the pre-hypertension range during stressful situations after ingestion of caffeine.

How Much Caffeine?

Caffeine effects may be dose-related. In a study published in the September 2008 issue of "Nutrition Research," the authors suggested that most caffeine research was not using a "normal cup of coffee" as the test dose. They found that even a so-called normal cup of coffee can have slight effects on blood pressure and mental alertness; stress may increase the magnitude of that change. Their study defines a "normal cup of coffee" as 12 ounces, with 140 mg of caffeine. In contrast, the Duke University study gave participants 3.5 mg of caffeine per kilogram of body weight; a 150 pound subject would have received about 238 mg.

Should You Drink Coffee?

Medline Plus states that up to four cups of coffee a day is not harmful for most people, but four "normal" cups would be twice the dose used in the Duke study. James D. Lane, associate research professor in the department of psychiatry and behavioral sciences at Duke and lead author of the study, thinks caffeine has a downside. "Our findings indicate that eliminating coffee and other caffeinated beverages from the diet could be a helpful way to decrease blood pressure and other stress reactions," Lane said in an interview for Duke's Health Library. "I think that people who feel 'stressed out' should at least consider quitting caffeine to see if they feel better. Quitting caffeine could be particularly beneficial for people suffering from high blood pressure, just as diet and exercise can help keep blood pressure under control." Remember, if you have symptoms such as irregular heart rhythms or questions about your health, you should consult your health care practitioner.