Caffeine is a bitter substance that stimulates your central nervous system. This means it can help boost your alertness and eliminate your drowsiness, according to MedlinePlus.com. Chances are you consume some caffeine on a regular basis if you drink coffee or tea, drink soda or eat chocolate. And although caffeine is widely consumed, it still is considered a drug and it comes with some potential disadvantages.
You are at a higher risk of undesirable side effects from caffeine if you have more than 500 to 600 milligrams of caffeine per day, which is contained in more than 4 cups of brewed coffee. Some immediate side effects of high caffeine consumption are nervousness, restlessness, upset stomach, rapid heartbeat, muscle tremors and irritability, according to MedlinePlus.com. In the long term, drinking a lot of caffeine throughout the day might lead to a vicious cycle of insomnia and fatigue, wherein you consistently lose sleep because of caffeine's effects, but then you need to drink caffeine to be alert during the day.
Your body should be able to tolerate about 200 to 300 milligrams of caffeine a day – equivalent to about 2 to 4 cups of brewed coffee – unless you are sensitive to caffeine. You might be more sensitive to caffeine if you are prone to stress, have high blood pressure, have headaches often, have an irregular heart beat and stomach ulcers or acid reflux, according to MedlinePlus.com. If you are extra-sensitive to caffeine, a single cup of coffee could prompt undesirable effects, such as restlessness.
You may increase your risk of fertility problems if you are a woman who has a lot of caffeine. Caffeine reduces muscle activity in your fallopian tubes, which are responsible for delivering eggs from your ovaries to your womb, according to the May 26, 2011 issue of the "British Journal of Pharmacology." Caffeine also can increase pregnancy complications because it crosses the placenta and reaches the fetus. Because the fetus has an immature metabolism, caffeine may linger in its system and build up to toxic levels. You may be at a higher risk of miscarriage and delivery of a low birth weight infant if your caffeine intake exceeds 200 to 300 milligrams per day.
Caffeine dependence can occur, according to a 1994 study published in The Journal of the American Medical Association. In the study, researchers determined that caffeine drinkers who had an average of 357 milligrams of caffeine per day showed classic drug dependence signs and symptoms such as a higher tolerance for caffeine with frequent use, a persistent desire or unsuccessful attempt at limiting their intake, withdrawal symptoms when they cut back on their intake and choosing to continue consuming caffeine in spite of the knowledge that caffeine might cause them psychological and physical problems. Common caffeine withdrawal symptoms -- headache, fatigue, irritability, trouble concentrating and depression -- have been observed at persistent intakes as low as 100 milligrams per day, but they are more common with higher consumption levels, according to the Linus Pauling Institute.
- The Journal of the American Medical Association: Caffeine Dependence Syndrome
- MedlinePlus.com: Caffeine in the Diet
- Health Services at Columbia University: Caffeine’s Effects on Health
- Linus Pauling Institute at Oregon State University: Coffee
- March of Dimes: Caffeine in Pregnancy
- British Journal of Pharmacology: Inhibitory Effect of caffeine on Pacemaker Activity in the Oviduct is Mediated by cAMP-Regulated Conductances