If you are consuming too much caffeine, you may experience trouble sleeping, heart palpitations, drug interactions, caffeine intoxication or physical dependence, according to the Mayo Clinic. Caffeine increases mental focus, counteracts fatigue and enhances athletic performance. There is a threshold, however, at which caffeine intake stops being useful and becomes harmful. And in rare cases, excess caffeine can be fatal.
Sources of Caffeine
A study in the "Journal of the American Dietetic Association" reports that Americans consume an average of 200 mg of caffeine daily. Most of this is from coffee, which contains anywhere from 60 to 150 mg per cup. Sodas are a large contributor of caffeine and can provide anywhere from 30 to 60 mg of caffeine per 12-oz. serving. Energy drinks are a growing source of caffeine in the American diet. Energy drinks will contribute 80 to 300 mg of caffeine to your diet on average.
Safe Levels of Caffeine
Most people can safely consume 200 to 300 mg of caffeine per day without harmful health effects. Pregnant women need to limit caffeine to about 300 mg per day; the "American Journal of Epidemiology" links intakes above this level to intrauterine growth retardation. Adverse affects are seen with caffeine intakes of 600 mg per day or more. Death can occur with intakes greater than 5,000 milligrams.
Safe Caffeine During Exercise
Caffeine can enhance your exercise performance and athletes frequently use caffeine for this purpose. The American Heart Association warns that caffeine use during exercise can stress the heart and induce cardiac arrhythmia. The level of caffeine that enhances your performance without increasing the risk for an adverse cardiovascular event attack is about 2.3 to 4.5 mg per pound of body weight according to the "American College of Emergency Physicians."
Caffeine-Medication Interactions
Caffeine can increase the effects of medications that stimulate the central nervous system. Medications such as those used to treat attention-deficit hyperactivity disorder, are central nervous system stimulants. People taking these should limit caffeine intake to avoid agitation, anxiety and disruptions in sleep. Caffeine can decrease the effects of a class of anti-anxiety medications, known as benzodiazepines.
Limit or Eliminate Excess Caffeine
The American Dietetic Association encourages people to limit intake of caffeine from sugar-sweetened beverages, as these have been linked to obesity and Type 2 diabetes. If you need to decrease the amount of caffeine you consume to a safe or more tolerable level, gradually reduce your intake over a period of time. Caffeine withdrawal can cause headaches.
References
- "Journal of the American Dietetic Association"; Food Sources and Intakes of Caffeine in the Diets of Persons in the United States; Carol Frary, MS, RD; January 2005
- Mayo Clinic; Caffeine - You May Like Caffeine's Effects, But How Much Is Too Much; March 2011
- "American Journal of Psychiatry"; Caffeine Intake, Tolerance, and Withdrawal in Women: A Population-Based Twin Study; Kenneth Kendler, M.D., et al; February 1999
- "American Journal of Epidemiology"; Relation of Caffeine Intake During Pregnancy to Intrauterine Growth Retardation and Preterm Birth; Isabel Foriter; June 1992
- "Journal of Psychopharmacology"; Anxiogenic Action of Caffeine: An Experimental Study on Rats; S.K. Bhattacharya, et al; 1997
- "Sports Medicine"; Caffeine and Endurance Performance; M.A. Tarnopolsky; August 1994
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